Advertisement

Factors Associated With Quality of Life Among People With Spinal Cord Injury: Application of the International Classification of Functioning, Disability and Health Model

      Abstract

      Chang F-H, Wang Y-H, Jang Y, Wang C-W. Factors associated with quality of life among people with spinal cord injury: application of the International Classification of Functioning, Disability and Health Model.

      Objective

      To identify the factors that influence an individual's quality of life (QOL) after spinal cord injury (SCI) based on the International Classification of Functioning, Disability and Health (ICF) framework.

      Design

      Cross-sectional exploratory study.

      Setting

      Taiwan community.

      Participants

      Community-dwelling adults (N=341) who had suffered an SCI at least 1 year previously and were between the ages of 18 and 60 years.

      Interventions

      Not applicable.

      Main Outcome Measure(s)

      A combination of self-report questionnaire and interview. The dependent variable, QOL, was measured by the abbreviated version of the World Health Organization Quality of Life, while the independent variables—participation, activity, impairment, and contextual factors—were measured using the Frenchay Activity Index, Barthel Index, and a demographic form.

      Results

      Multivariate analysis results indicated that participation, activity, and marital status are significant factors in the QOL outcome. Results also indicated that among the various factors that affect each domain of QOL (physical health, psychological health, social relationships, and environment), participation was the strongest determinant.

      Conclusions

      The ICF provided an excellent framework with which to explore the factors influencing QOL after SCI. The results demonstrated that marital status, participation, and activity exert the strongest influence on QOL, while impairment and other variables do not directly influence QOL.

      Key Words

      List of Abbreviations:

      BI (Barthel Index), FAI (Frenchay Activity Index), ICF (International Classification of Functioning, Disability and Health), QOL (quality of life), SCI (spinal cord injuries), WHO (World Health Organization), WHOQOL (World Health Organization Quality of Life), WHOQOL-BREF (abbreviated version of World Health Organization Quality of Life)
      SPINAL CORD INJURY (SCI) results in complete or incomplete loss of function below the level of the lesion and has a broad impact on medical, social, psychological, and economic conditions for those directly affected, their paid and unpaid caregivers, and the community.
      • Pulaski K.H.
      Adult neurological dysfunction.
      Rehabilitation focuses on the consequences of the injury, with the goal of enabling an individual with SCI to be an active and productive member of society, well integrated into the community, and highly satisfied with his/her quality of life (QOL).
      • Pulaski K.H.
      Adult neurological dysfunction.
      • Whiteneck G.G.
      The 44th annual John Stanley Coulter Lecture Measuring what matters: key rehabilitation outcomes.
      Recently, QOL has gained recognition as an important measure of the success of rehabilitation programs for individuals with disabilities.
      • Robert M.K.
      Quality of life: an outcomes perspective.
      • Tulsky D.S.
      • Rosenthal M.
      Quality of life measurement in rehabilitation medicine: building an agenda for the future.
      • Hammell K.W.
      Exploring quality of life following high spinal cord injury: a review and critique.
      The concept of QOL, proposed by the World Health Organization (WHO), has been defined as “individuals' perceptions of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.”
      WHOQOL group
      Development of the WHOQOL: rationale and current status.
      (p28)
      The International Classification of Functioning, Disability and Health (ICF) is a well-known conceptual framework that describes the consequences of injury.
      World Health Organization
      International Classification of Functioning, Disability and Health (ICF).
      The ICF model includes 3 components of the dimension of functioning: body functions and structures, activity, and participation. Problems or difficulties in these 3 components are conceptualized as impairments, activity limitations, and participation restrictions, respectively. Dimensions of functioning and disability are thought to be affected by health conditions and contextual factors (personal and environmental factors).
      World Health Organization
      International Classification of Functioning, Disability and Health (ICF).
      Moreover, impairment often results in activity limitations, leading to additional participation restrictions.
      World Health Organization
      International Classification of Functioning, Disability and Health (ICF).
      • Rimmer J.H.
      Use of the ICF in identifying factors that impact participation in physical activity/rehabilitation among people with disabilities.
      The ICF model emphasizes objective features of disability but neglects the subjective experience of the person involved.
      • Coster W.
      • Khetani M.A.
      Measuring participation of children with disabilities: issues and challenges.
      • Wynia K.
      • Middel B.
      • de Ruiter H.
      • et al.
      Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and use of a measure for perception of disabilities.
      The concept of QOL may serve to address this oversight.
      • Wynia K.
      • Middel B.
      • de Ruiter H.
      • et al.
      Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and use of a measure for perception of disabilities.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      As a construct representing an individual's overall summation of all components of his/her situation, QOL is considered an integral part of the disease-functioning continuum.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • Post M.W.M.
      • de Witte L.P.
      • Schrijvers A.J.
      Quality of life and the ICIDH: towards an integrated conceptual model for rehabilitation outcomes research.
      QOL affects, and is affected by, all the disability dimensions.
      • Whiteneck G.G.
      The 44th annual John Stanley Coulter Lecture Measuring what matters: key rehabilitation outcomes.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • Post M.W.M.
      • de Witte L.P.
      • Schrijvers A.J.
      Quality of life and the ICIDH: towards an integrated conceptual model for rehabilitation outcomes research.
      To understand the health and well-being of individuals with disabilities from an integrated perspective, the concept of QOL and the ICF model need to be incorporated.
      • Wade D.T.
      • Halligan P.
      Recent advances in rehabilitation.
      Previous research demonstrates a lower QOL in the SCI population than in the non-SCI population.
      • Leduc B.E.
      • Lepage Y.
      Health-related quality of life after spinal cord injury.
      • Post M.W.M.
      • van Dijk A.J.
      • van Asbeck F.W.
      • Schrijvers A.J.
      Life satisfaction of persons with spinal cord injury compared to a population group.
      • Westgren N.
      • Levi R.
      Quality of life and traumatic spinal cord injury.
      Although multiple factors have been identified as associated with QOL among people with SCI, the findings have been inconsistent. For example, researchers have found that QOL after SCI appears to be influenced by severity of impairment, age, sex, race, marital status, time since injury, educational level, medical complications, self-perceived health, mobility, environmental surroundings, work, and participation in various domains.
      • McColl M.A.
      • Arnold R.
      • Charlifue S.
      • Glass C.
      • Savic G.
      • Frankel H.
      Aging, spinal cord injury, and quality of life: structural relationships.
      • Lin K.
      • Chuang C.
      • Kao M.
      • Lien I.
      • Tsauo J.
      Quality of life of spinal cord injured patients in Taiwan: a subgroup study.
      • Barker R.N.
      • Kendall M.D.
      • Amsters D.I.
      • Pershouse K.J.
      • Haines T.P.
      • Kuipers P.
      The relationship between quality of life and disability across the lifespan for people with spinal cord injury.
      • Jain N.B.
      • Sullivan M.
      • Kazis L.E.
      • Tun C.G.
      • Garshick E.
      Factors associated with health-related quality of life in chronic spinal cord injury.
      • Putzke J.D.
      • Richards J.S.
      • Hicken B.L.
      • DeVivo M.J.
      Predictors of life satisfaction: a spinal cord injury cohort study.
      • Riggins M.S.
      • Kankipati P.
      • Oyster M.L.
      • Cooper R.A.
      • Boninger M.L.
      The relationship between quality of life and change in mobility 1 year postinjury in individuals with spinal cord injury.
      • Richards J.S.
      • Bombardier C.H.
      • Tate D.
      • et al.
      Access to the environment and life satisfaction after spinal cord injury.
      • Post M.W.M.
      • de Witte L.P.
      • van Asbeck F.W.
      • van Dijk A.J.
      • Schrijvers A.J.
      Predictors of health status and life satisfaction in spinal cord injury.
      • Whiteneck G.
      • Meade M.A.
      • Dijkers M.
      • Tate D.G.
      • Bushnik T.
      • Forchheimer M.B.
      Environmental factors and their role in participation and life satisfaction after spinal cord injury.
      However, other researchers have not found significant relationships.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • Post M.W.M.
      • van Dijk A.J.
      • van Asbeck F.W.
      • Schrijvers A.J.
      Life satisfaction of persons with spinal cord injury compared to a population group.
      • Westgren N.
      • Levi R.
      Quality of life and traumatic spinal cord injury.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
      Long-term adjustment and community reintegration following spinal cord injury.
      • McColl M.A.
      • Stirling P.
      • Walker J.
      • Corey P.
      • Wilkins R.
      Expectations of independence and life satisfaction among ageing spinal cord injured adults.
      • Putzke J.D.
      • Elliot T.R.
      • Richards J.S.
      Marital status and adjustment 1 year post-spinal-cord-injury.
      • Tate D.G.
      • Kalpakjian C.Z.
      • Forchheimer M.B.
      Quality of life issues in individuals with spinal cord injury.
      Moreover, only a few studies on individuals with SCI have adopted a systematic and comprehensive conceptual model for understanding the factors influencing QOL among people with SCI.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • McColl M.A.
      • Arnold R.
      • Charlifue S.
      • Glass C.
      • Savic G.
      • Frankel H.
      Aging, spinal cord injury, and quality of life: structural relationships.
      • Post M.W.M.
      • de Witte L.P.
      • van Asbeck F.W.
      • van Dijk A.J.
      • Schrijvers A.J.
      Predictors of health status and life satisfaction in spinal cord injury.
      • Whiteneck G.
      • Meade M.A.
      • Dijkers M.
      • Tate D.G.
      • Bushnik T.
      • Forchheimer M.B.
      Environmental factors and their role in participation and life satisfaction after spinal cord injury.
      • Mortenson W.B.
      • Noreau L.
      • Miller W.C.
      The relationship between and predictors of quality of life after spinal cord injury at 3 and 15 months after discharge.
      • Mulroy S.J.
      • Winstein C.J.
      • Kulig K.
      • et al.
      Secondary mediation and regression analyses of the PTClinResNet database: determining causal relationships among the International Classification of Functioning, Disability and Health levels for four physical therapy intervention trials.
      This study aimed to replicate and extend previous research that examined factors associated with QOL among individuals with SCI by using the ICF model. Applying the ICF model in this study will not only help researchers and clinicians acknowledge the potential factors that may influence the subjective rehabilitation outcomes of individuals with SCI but may also provide a broader picture of the interrelationships between impairment, activity, participation, contextual factors, and QOL.

      Methods

      Sample

      A cross-sectional sample was used for this study. To allow for an adequate sample for analysis, our study used data from 2 sources: a teaching hospital and a national SCI association. Subjects eligible for participation were persons who (1) had sustained an SCI, (2) were at least 1 year postinjury, (3) were between the ages of 18 and 60 years at the time of the survey, and (4) were living in the community.

      Data Collection

      All members from the SCI association were contacted by mail to request their participation in the study and were enrolled upon completion of a self-administered questionnaire in 2001. After filling out the questionnaire, they were asked to return it by mail or return it directly to a home-visit social worker. If the subject could not write, a family member or social worker helped complete the questionnaire by writing down the subject's answers.
      All eligible subjects in the teaching hospital were identified from the medical records of the hospital and were contacted by mail or telephone. After obtaining consent, an occupational therapist and 2 occupational therapy students asked the subjects to fill out a questionnaire in 2003. If a participant was unable to write because of disability, the interviewer held the questionnaire for the subject to read and wrote down the answers he/she provided. All study procedures were reviewed and approved by the institutional internal review board.

      Measures

      A questionnaire was constructed to assess demographics, impairment, activity, participation, and QOL. It took 40 to 60 minutes to complete the questionnaire.

      Demographics, impairment, activity, and participation

      Demographic variables in this study include both personal factors and environmental factors. Personal factors taken into account included sex, age, marital status, education level, and time since injury. Environmental factors included living situation (whether the participant lived at home or in another setting) and the floor of the building on which the participant lived (on the first floor or building with elevator, second floor or above without elevator).
      Impairment was measured by 2 variables: injury level (level and completeness of SCI) and the presence of complications. The injury level was obtained by asking the participants which level of injury (cervical, thoracic, lumbar, or sacral) they had and whether the injury was complete or incomplete. Presence of complications was measured by asking the participants whether, during the past month, they had experienced 1 or more of the 8 common secondary complications of SCI: urinary tract infections, pressure sores, spasticity, pain related to the injury, contractures, respiratory problems, edema, and excessive sweating.
      Activity was measured by independence in personal care and transportation. Transportation independence was evaluated by the question, “Can you use public transportation or drive a car independently?” Independence in personal care was measured by using the 10-item Barthel Index (BI), a reliable and valid measure.
      • Mahoney F.l.
      • Barthel D.W.
      Functional evaluation: the Barthel index.
      • Roy C.W.
      • Togneri J.
      • Hay E.
      • Pentland B.
      An inter-rater reliability study of the Barthel index.
      It scores the participant's level of independence in 10 fundamental items of activities of daily living: feeding, grooming, bowels, bladder, dressing, toilet use, bathing, transfers, walking, and stairs. Possible BI scores range from 0 to 20, with a higher score indicating greater independence.
      • Mahoney F.l.
      • Barthel D.W.
      Functional evaluation: the Barthel index.
      Participation was measured by using the Frenchay Activity Index (FAI).
      • Holbrook M.
      • Skilbeck C.E.
      An activities index for use with stroke patients.
      The FAI measures a person's frequency of activity participation. It comprises 15 activities (eg, local shopping, social occasions, actively pursuing a hobby, and gainful employment), and each rated from 1 to 4.
      • Holbrook M.
      • Skilbeck C.E.
      An activities index for use with stroke patients.
      The reliability and validity of the FAI have been proved to be satisfactory and suitable for use for individuals with SCI.
      • Hsieh C.L.
      • Jang Y.
      • Yu T.Y.
      • Wang W.C.
      • Sheu C.F.
      • Wang Y.H.
      A Rasch analysis of the Frenchay Activities Index in patients with spinal cord injury.

      Quality of life

      QOL was assessed using the abbreviated version of the World Health Organization Quality of Life (WHOQOL-BREF).
      WHOQOL Group
      The World Health Organization quality of life assessment (WHOQOL): development and general psychometric properties.
      The WHOQOL-BREF was developed as a self-report questionnaire containing 26 items to be rated on a 5-point Likert scale. Among these items, 24 items make up the 4 domains of QOL: physical health (7 items), psychological health (6 items), social relationships (3 items), and environment (8 items); the other 2 items measure overall self-perceived QOL and health. A higher score indicates a better QOL. WHOQOL-BREF demonstrates satisfactory internal consistency and discriminant validity among individuals with SCI.
      • Jang Y.
      • Hsieh C.L.
      • Wang Y.H.
      • Wu Y.H.
      A validity study of the WHOQOL-BREF assessment in persons with traumatic spinal cord injury.
      Following the scoring guidelines used in the manual of the WHOQOL-BREF, each domain's score was calculated by multiplying the mean score for all items included in each domain by a factor of 4.
      WHOQOL Group
      The World Health Organization quality of life assessment (WHOQOL): development and general psychometric properties.
      The score for each domain therefore ranges from 4 to 20. The overall QOL score is obtained by summing the mean score of each domain.

      Statistical Analysis

      All analyses were performed using SPSS.a We first employed bivariate analyses (t test, 1-way analysis of variance, and the Pearson correlation coefficient test) to examine the relationships between the dependent variable and each independent variable. Variables that proved significantly associated with QOL were then included in the multiple linear regression analysis. The regression analysis was used to obtain the model predicting QOL. The collinearity among independent variables was tested. For all calculations, a P value of <.05 was considered statistically significant. Finally, we conducted 4 regression models to examine the factors that affect each domain of QOL (as observed in each subscale of World Health Organization Quality of Life [WHOQOL]), using all the significant variables from the results of bivariate analysis. Since multiple models were tested, we applied the Bonferonni correction of the alpha value. The significance level for the estimates was an alpha value of .0125.

      Results

      Of the 946 members of the SCI association, 320 persons returned the questionnaire (33.8% of the total recruitment pool). Of these, 38 did not fulfill the criteria of this study and 110 had incomplete data, leaving 172 eligible participants. In the teaching hospital, of the 260 persons who fulfilled the study criteria, 68 could not be contacted and 23 refused to participate. The remaining 169 individuals were included in the study (65% of the total recruitment pool at this site). There were no statistically significant differences between the participants from the 2 recruitment sites in terms of age (t=.17, P=.868), sex (χ2=3.78, P=.052), marital status (χ2=2.12, P=.145), education (χ2=.57, P=.449), or time since injury (t=.26, P=.794). One difference, however, was that the participants from the SCI association included more individuals with tetraplegia (χ2=15.41, P=.001).
      Table 1 presents the general characteristics and the mean scores of BI and FAI of the participants. The participants' ages ranged from 18 to 60 years, with a mean of 39.59 years. Time since injury varied from 1 to 38 years (mean=10.11y). The BI showed a mean score of 10.71 and had a range of 0 to 20; FAI showed a mean score of 28.30 and ranged from 15 to 59.
      Table 1General Characteristics of the Participants
      CategoryValues
      Personal factors
       Sex
        Female58 (17.0)
        Male283 (83.0)
       Age (y)
        35 and younger121 (35.5)
        36–44109 (32.0)
        45 and older111 (32.6)
       Marital status
        Single/divorced/widowed134 (39.3)
        Married/cohabit207 (60.7)
       Education
        Below high school134 (39.3)
        High school147 (43.1)
        Above high school60 (17.6)
       Time since injury (y)10.11±06.50
      Environmental factors
       Living situation
        Other50 (14.7)
        Home291 (85.3)
       Floor that live on
        Second floor or above without elevator121 (35.5)
        First floor or building with elevator220 (64.5)
      Impairment
       Injury level
        Complete tetraplegia73 (21.4)
        Incomplete tetraplegia61 (17.9)
        Complete paraplegia145 (42.5)
        Incomplete paraplegia62 (18.2)
       Complications
        Yes278 (81.5)
        No63 (18.5)
      Activity
       Transportation
        Dependent172 (50.4)
        Independent169 (49.6)
       BI10.71±6.03
      Participation
       FAI28.30±10.71
      NOTE. Values are n (%) or mean ± SD.
      For the WHOQOL total and subscales, the mean scores ± SD were 11.74±2.94 on the physical health domain; 11.49±3.09 on the psychological health domain; 12.00±2.78 on the social relationships domain; and 11.79±2.55 on the environment domain. The overall WHOQOL scores ranged from 5 to 19, with a mean ± SD of 11.66±2.45.

      Factors Related to QOL

      Bivariate analysis

      Table 2 contains the bivariate analysis results of the overall WHOQOL score and the independent variables. Within the personal factors, we found that those who were married, had a higher education level, were younger, and had a longer time since injury were associated with a better overall WHOQOL score (P<.05).
      Table 2Bivariate Analysis Results of the WHOQOL Score and ICF Components
      CategoryMean WHOQOL Score/Pearson Correlation CoefficientP
      Personal factors
       Sex.424
        Female11.45±2.12
        Male11.70±2.51
       Age (y).032
      P<.05.
        35 and younger12.01±2.37
      P<.05.
        36–4411.76±2.37
        45 and older11.18±2.56
       Marital status.027
      P<.05.
        Single/divorced/widowed11.38±2.39
        Married/cohabit11.96±2.48
      P<.05.
       Education.009
      P<.01.
        Below high school11.17±2.48
        High school12.06±2.32
        Above high school11.76±2.53
       Time since injuryr=.108
      P<.05.
      .046
      P<.05.
      Environmental factors
       Living situation.128
        Other11.17±2.86
        Home11.74±2.37
       Floor that live on.452
        Second floor or above without elevator11.52±2.61
        First floor or building with elevator11.73±2.36
      Impairment
       Injury level.001
      P<.01.
        Complete tetraplegia11.05±2.50
        Incomplete tetraplegia10.96±2.39
        Complete paraplegia12.10±2.29
      P<.05.
        Incomplete paraplegia12.03±2.56
       Complications.115
        Yes11.56±2.37
        No12.01±2.76
      Activity
       Transportation<.001
      P<.01.
        Dependent10.73±2.37
        Independent12.57±2.17
       BIr=.356<.001
      P<.01.
      Participation
       FAIr=.451
      P<.01.
      <.001
      P<.01.
      NOTE. Values are mean ± SD or Pearson correlation coefficient.
      low asterisk P<.05.
      P<.01.
      Of the 2 impairment variables, only the injury level was significantly associated with WHOQOL score (P<.001). Those with complete paraplegia had the highest QOL than did those with other injury levels. Activity variables (independence in personal care and transportation) and participation were all significantly associated with WHOQOL score (P<.001). Those who were more independent and participated more in their lives had better QOL. None of the environmental variables were significantly correlated to WHOQOL.

      Multivariate analysis

      • 1
        The factors that determine the overall QOL
      Using the results from table 2, we built a multiple linear regression model of QOL that included variables that had significant relationships to the overall WHOQOL scores (according to bivariate analysis). Results of the regression analysis are shown in table 3. The model for the total WHOQOL score explained 26.9% of the variance, F12,328=10.039, P<.001. Among the personal factors, only marital status was significantly associated with WHOQOL score, after controlling for other variables (P<.05). Those who were married had a higher WHOQOL score than did those who were single. Activity and participation variables were significantly associated with WHOQOL. Those who were more independent on personal care and transportation reported a higher WHOQOL score than did those who were less independent (P<.05); those who reported more participation had a higher WHOQOL score than did those who reported less participation (P<.05).
      Table 3The Multiple Regression Model for the Total Score of WHOQOL
      CategoryCoefficientStandard ErrorStandardized CoefficientP
      Personal factors
       Marital status
        Married.622.261.127.018
      P<.05.
        Single (reference)
       Education
        Below high school−.364.345−.073.291
        High school.132.330.027.689
        Above high school (reference group)
       Age (y)
        35 and younger.623.349.122.076
        36–44.346.303.066.254
        45 and above (reference group)
       Time since injury.022.020.058.270
      Impairment
       Injury level
        Complete tetraplegia.677.382.113.077
        Incomplete tetraplegia−.353.341−.055.301
        Complete paraplegia (reference group)−.329.337−.052.329
      Activity
       Transportation.707.305.145.021
      P<.05.
       BI.069.032.171.030
      P<.05.
      Participation
       FAI.057.016.250<.001
      P<.01.
      NOTE. The reference group is the group that has all dummy variables set to 0.
      low asterisk P<.05.
      P<.01.
      We also inspected collinearity for the regression model. The result indicated that the variance inflation factor ranged from 1.236 to 2.742 and the tolerance ranged from .365 to .809. The results showed that collinearity was not a concern.
      • 2
        The factors that determine each domain of QOL
      Last, we applied 4 multiple regression analyses to determine the factors that impact the 4 domains of QOL: physical health, psychological health, social relationships, and environment (table 4). Based on the results, physical health was associated with injury level, activity (independence in personal care and transportation), and participation. All 3 other domains (psychological health, social relationships, and environment) were significantly associated only with participation (standardized coefficient=.256, .208, and .211, respectively; P<.013).
      Table 4The Results of the Regression Analysis for Each Domain of QOL
      CategoryStandardized Coefficient
      Physical HealthPsychological HealthSocial RelationshipsEnvironment
      Personal factors
       Marital status
        Married.089.109.135.124
        Single (reference group)
       Education
        Below high school−.065−.053−.020−.092
        High school.039.049−.014−.010
        Above high school (reference group)
       Age (y)
        35 and younger.146.122.056.071
        36–44.094.100.023−.005
        45 and above (reference group)
       Time since injury.051.106−.014.020
      Impairment
       Injury level
        Complete tetraplegia.037.155.144.084
        Incomplete tetraplegia−.140
      P <.0125.
      .020.015−.043
        Incomplete paraplegia−.086−.058.017−.022
        Complete paraplegia (reference group)
      Activity
       Transportation.261
      P <.0125.
      .125.076.117
       BI.157
      P <.0125.
      .069.135.101
      Participation
       FAI.201
      P <.0125.
      .256
      P <.0125.
      .208
      P <.0125.
      .211
      P <.0125.
      NOTE. The reference group is the group that has all dummy variables set to 0. Bonferonni correction of the α value for multiple testing was applied to the 4 regression analyses. The significance level is α=.0125.
      low asterisk P <.0125.

      Discussion

      One of the proposed aims of future work on the ICF is to establish “links with QOL concepts and the measurement of subjective well-being.”
      World Health Organization
      International Classification of Functioning, Disability and Health (ICF).
      (p251) Responding to this aim, our study demonstrated the relationships between QOL and the ICF by relating the ICF components (impairment, activity, participation, and contexture factors) to QOL, which is supported by previous study findings.
      • Barker R.N.
      • Kendall M.D.
      • Amsters D.I.
      • Pershouse K.J.
      • Haines T.P.
      • Kuipers P.
      The relationship between quality of life and disability across the lifespan for people with spinal cord injury.
      • Jain N.B.
      • Sullivan M.
      • Kazis L.E.
      • Tun C.G.
      • Garshick E.
      Factors associated with health-related quality of life in chronic spinal cord injury.
      Among these components, activity (independence in personal care and transportation), participation, and personal factor–marital status proved to be the significant factors predicting the overall QOL.
      Of these significant factors, participation demonstrated the most powerful influence on QOL. Not only was it the most significant predictor of overall WHOQOL score, but it also demonstrated the most significant impact across each individual domain of QOL. Previous research similarly indicated that participation in home, work, social, and leisure activities is highly related to QOL.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • Putzke J.D.
      • Richards J.S.
      • Hicken B.L.
      • DeVivo M.J.
      Predictors of life satisfaction: a spinal cord injury cohort study.
      • Chan S.C.
      • Chan A.P.
      User satisfaction, community participation and quality of life among Chinese wheelchair users with spinal cord injury: a preliminary study.
      Researchers also found that individuals who had greater community participation had better QOL.
      • Barker R.N.
      • Kendall M.D.
      • Amsters D.I.
      • Pershouse K.J.
      • Haines T.P.
      • Kuipers P.
      The relationship between quality of life and disability across the lifespan for people with spinal cord injury.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
      Long-term adjustment and community reintegration following spinal cord injury.
      Participation is a complex concept whose characteristics and dimensions are frequently disputed by scholars and practitioners. Nevertheless, participation has proven to be an important rehabilitation goal for people with disabilities and has been used as a primary mean to reflect a “better life.”
      • Brown M.
      • Dijkers M.P.
      • Gordon W.A.
      • Ashman T.
      • Charatz H.
      • Cheng Z.
      Participation objective, participation subjective: a measure of participation combining outsider and insider perspectives.
      Previous research has also indicated that individuals with SCI expressed a strong desire to participate in daily, productive, and social activities.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
      Long-term adjustment and community reintegration following spinal cord injury.
      This study confirmed the importance of participation for individuals with SCI by demonstrating its significant relationship with QOL. On the basis of this finding, we can assert that the level of participation in various life situations influences one's satisfaction with his/her current state and well-being.
      Our findings also indicated that individuals with higher independence in activity (personal care and transportation) had higher QOL. This finding supports results from previous studies, in which researchers found that independence in mobility and transportation in the community was related to higher QOL.
      • Riggins M.S.
      • Kankipati P.
      • Oyster M.L.
      • Cooper R.A.
      • Boninger M.L.
      The relationship between quality of life and change in mobility 1 year postinjury in individuals with spinal cord injury.
      • Richards J.S.
      • Bombardier C.H.
      • Tate D.
      • et al.
      Access to the environment and life satisfaction after spinal cord injury.
      Similarly, the significant relationship between independence in personal care and QOL, especially the physical health domain, is consistent with previous research findings among patients with stroke.
      • Jang Y.
      • Hsieh C.L.
      • Wang Y.H.
      • Wu Y.H.
      A validity study of the WHOQOL-BREF assessment in persons with traumatic spinal cord injury.
      • Chan S.C.
      • Chan A.P.
      User satisfaction, community participation and quality of life among Chinese wheelchair users with spinal cord injury: a preliminary study.
      This finding suggests that this relationship may exist in people with other disabilities.
      Like most previous studies, our results confirmed that marital status is a significant predictor for QOL.
      • Putzke J.D.
      • Elliot T.R.
      • Richards J.S.
      Marital status and adjustment 1 year post-spinal-cord-injury.
      Previous research has shown that family support is a significant predictor of QOL among individuals with SCI, especially at later time points after injury.
      • Mortenson W.B.
      • Noreau L.
      • Miller W.C.
      The relationship between and predictors of quality of life after spinal cord injury at 3 and 15 months after discharge.
      The benefit of marriage may result from the social support from the spouse. Because individuals with SCI are less likely to engage in community social activities, the spousal relation appears to be particularly important in providing the social support that would otherwise be lacking.
      • Price P.
      • Stephenson S.
      • Krantz L.
      • Ward K.
      Beyond my front door: the occupational and social participation of adults with spinal cord injury.
      Across all the regression results, the impairment variable injury level did not significantly impact the overall QOL, or any individual domain of QOL, except physical health. These results indicated little to no direct relationship between impairments and QOL, supporting the findings of most previous studies on this subject.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      • Post M.W.M.
      • van Dijk A.J.
      • van Asbeck F.W.
      • Schrijvers A.J.
      Life satisfaction of persons with spinal cord injury compared to a population group.
      • Putzke J.D.
      • Richards J.S.
      • Hicken B.L.
      • DeVivo M.J.
      Predictors of life satisfaction: a spinal cord injury cohort study.
      In fact, several studies have found an indirect relationship between impairment and QOL. One study has suggested that impairments due to SCI affect QOL through their impact on activities and participation.
      • Post M.
      • Noreau L.
      Quality of life after spinal cord injury.
      Similarly, McColl et al
      • McColl M.A.
      • Arnold R.
      • Charlifue S.
      • Glass C.
      • Savic G.
      • Frankel H.
      Aging, spinal cord injury, and quality of life: structural relationships.
      asserted that the level of injury is only an indirect predictor of QOL, through its relationship with other disability-related variables. This result can also be interpreted by the ICF framework. According to the ICF, participation is the result of a complex interaction among factors including an individual's health, body structure and function, activity, and personal and environmental factors.
      World Health Organization
      International Classification of Functioning, Disability and Health (ICF).
      The impairment of body structure and function may lead to participation restriction. Therefore, while participation directly impacts QOL, impairment can be perceived as an indirect influence, operating through the mechanism of activity. On the basis of this finding, clinicians need to be aware that impairment may not be the most critical determinant of QOL for people with SCI even though its potential influence on participation and other rehabilitation outcomes cannot be ignored.

      Study Limitations

      The findings of this study must be interpreted with caution. First, both the convenience nature of the recruited sample and the restrictiveness of the geographic area limit the generalization of the findings. One should not make inferences at the population level. Second, this study was a cross-sectional study. Thus, the causal relationship cannot be established on the basis of study results. Future longitudinal studies should be conducted and use modeling analysis (eg, path analysis) to examine the causal relationships between those significant factors and QOL. Third, the study subjects completed the questionnaire in 2 different ways and there was a 2-year gap between when the data were collected from the 2 sites. These differences may affect the sample representativeness. Nevertheless, given the few significant differences on most of the demographic characteristics between the 2 samples, this concern can be minimized. Fourth, the number of variables examined was limited, because of the length of the assessment. Some psychosocial factors, such as locus of control and discrimination, may be influential to QOL but were not included.
      • Brown M.
      • Dijkers M.P.
      • Gordon W.A.
      • Ashman T.
      • Charatz H.
      • Cheng Z.
      Participation objective, participation subjective: a measure of participation combining outsider and insider perspectives.
      • Myaskovsky L.
      • Burkitt K.H.
      • Lichy A.M.
      • et al.
      The association of race, cultural factors, and health-related quality of life in persons with spinal cord injury.
      In future studies, the impact of a wide range of psychosocial variables should be considered to more accurately determine the predictive factors of QOL.

      Conclusions

      In recent years, the focus of rehabilitation outcomes has shifted from the illness itself to a broader picture of well-being. Along with the growing acceptance of the ICF and the importance of QOL, the key to successful rehabilitation management is to understand the relationships between QOL and the components (impairment, activity, participation, and contextual factors) of the disability and address those with the most potential for improvement. This study is unique in its use of the ICF model as a means of understanding the factors influencing QOL among individuals with SCI. Our findings clearly indicate the presence of a relationship between the ICF components and QOL. The results also demonstrate that participation has a direct and powerful relation to QOL in individuals with SCI. Clinically, these findings elucidate the significant factors of a successful rehabilitation for individuals with SCI, serving as a helpful reference point for active practitioners.
      • a
        SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606.

      References

        • Pulaski K.H.
        Adult neurological dysfunction.
        in: Crepeau E.B. Cohn E.S. Schell B.A.B. Willard and Spackman's occupational therapy. 10th ed. Lippincott Williams & Wilkins, Philadelphia2003: 767-788
        • Whiteneck G.G.
        The 44th annual John Stanley Coulter Lecture.
        Arch Phys Med Rehabil. 1994; 75: 1073-1076
        • Robert M.K.
        Quality of life: an outcomes perspective.
        Arch Phys Med Rehabil. 2002; 83: S44-S50
        • Tulsky D.S.
        • Rosenthal M.
        Quality of life measurement in rehabilitation medicine: building an agenda for the future.
        Arch Phys Med Rehabil. 2002; 83: S1-S3
        • Hammell K.W.
        Exploring quality of life following high spinal cord injury: a review and critique.
        Spinal Cord. 2004; 42: 491-502
        • WHOQOL group
        Development of the WHOQOL: rationale and current status.
        Int J Ment Health. 1994; 23: 28
        • World Health Organization
        International Classification of Functioning, Disability and Health (ICF).
        World Health Organization, Geneva2001
        • Rimmer J.H.
        Use of the ICF in identifying factors that impact participation in physical activity/rehabilitation among people with disabilities.
        Disabil Rehabil. 2006; 28: 1087-1095
        • Coster W.
        • Khetani M.A.
        Measuring participation of children with disabilities: issues and challenges.
        Disabil Rehabil. 2008; 30: 639-648
        • Wynia K.
        • Middel B.
        • de Ruiter H.
        • et al.
        Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and use of a measure for perception of disabilities.
        Disabil Rehabil. 2009; 31: 1008-1017
        • Post M.
        • Noreau L.
        Quality of life after spinal cord injury.
        J Neurol Phys Ther. 2005; 29: 139-146
        • Post M.W.M.
        • de Witte L.P.
        • Schrijvers A.J.
        Quality of life and the ICIDH: towards an integrated conceptual model for rehabilitation outcomes research.
        Clin Rehabil. 1999; 13: 5-15
        • Wade D.T.
        • Halligan P.
        Recent advances in rehabilitation.
        Clin Rehabil. 2003; 17: 349-354
        • Leduc B.E.
        • Lepage Y.
        Health-related quality of life after spinal cord injury.
        Disabil Rehabil. 2002; 24: 196-202
        • Post M.W.M.
        • van Dijk A.J.
        • van Asbeck F.W.
        • Schrijvers A.J.
        Life satisfaction of persons with spinal cord injury compared to a population group.
        Scand J Rehabil Med. 1998; 30: 23-30
        • Westgren N.
        • Levi R.
        Quality of life and traumatic spinal cord injury.
        Arch Phys Med Rehabil. 1998; 79: 1433-1439
        • McColl M.A.
        • Arnold R.
        • Charlifue S.
        • Glass C.
        • Savic G.
        • Frankel H.
        Aging, spinal cord injury, and quality of life: structural relationships.
        Arch Phys Med Rehabil. 2003; 84: 1137-1144
        • Lin K.
        • Chuang C.
        • Kao M.
        • Lien I.
        • Tsauo J.
        Quality of life of spinal cord injured patients in Taiwan: a subgroup study.
        Spinal Cord. 1997; 35: 841-849
        • Barker R.N.
        • Kendall M.D.
        • Amsters D.I.
        • Pershouse K.J.
        • Haines T.P.
        • Kuipers P.
        The relationship between quality of life and disability across the lifespan for people with spinal cord injury.
        Spinal Cord. 2009; 47: 149-155
        • Jain N.B.
        • Sullivan M.
        • Kazis L.E.
        • Tun C.G.
        • Garshick E.
        Factors associated with health-related quality of life in chronic spinal cord injury.
        Am J Phys Med Rehabil. 2007; 86: 387-396
        • Putzke J.D.
        • Richards J.S.
        • Hicken B.L.
        • DeVivo M.J.
        Predictors of life satisfaction: a spinal cord injury cohort study.
        Arch Phys Med Rehabil. 2002; 83: 555-561
        • Riggins M.S.
        • Kankipati P.
        • Oyster M.L.
        • Cooper R.A.
        • Boninger M.L.
        The relationship between quality of life and change in mobility 1 year postinjury in individuals with spinal cord injury.
        Arch Phys Med Rehabil. 2011; 92: 1027-1033
        • Richards J.S.
        • Bombardier C.H.
        • Tate D.
        • et al.
        Access to the environment and life satisfaction after spinal cord injury.
        Arch Phys Med Rehabil. 1999; 80: 1501-1506
        • Post M.W.M.
        • de Witte L.P.
        • van Asbeck F.W.
        • van Dijk A.J.
        • Schrijvers A.J.
        Predictors of health status and life satisfaction in spinal cord injury.
        Arch Phys Med Rehabil. 1998; 79: 395-401
        • Whiteneck G.
        • Meade M.A.
        • Dijkers M.
        • Tate D.G.
        • Bushnik T.
        • Forchheimer M.B.
        Environmental factors and their role in participation and life satisfaction after spinal cord injury.
        Arch Phys Med Rehabil. 2004; 85: 1793-1803
        • Boschen K.A.
        • Tonack M.
        • Gargaro J.
        Long-term adjustment and community reintegration following spinal cord injury.
        Int J Rehabil Res. 2003; 26: 157-164
        • McColl M.A.
        • Stirling P.
        • Walker J.
        • Corey P.
        • Wilkins R.
        Expectations of independence and life satisfaction among ageing spinal cord injured adults.
        Disabil Rehabil. 1999; 21: 231-240
        • Putzke J.D.
        • Elliot T.R.
        • Richards J.S.
        Marital status and adjustment 1 year post-spinal-cord-injury.
        J Clin Psychol Med Settings. 2001; 8: 101-107
        • Tate D.G.
        • Kalpakjian C.Z.
        • Forchheimer M.B.
        Quality of life issues in individuals with spinal cord injury.
        Arch Phys Med Rehabil. 2002; 83: S18-S25
        • Mortenson W.B.
        • Noreau L.
        • Miller W.C.
        The relationship between and predictors of quality of life after spinal cord injury at 3 and 15 months after discharge.
        Spinal Cord. 2010; 48: 73-79
        • Mulroy S.J.
        • Winstein C.J.
        • Kulig K.
        • et al.
        Secondary mediation and regression analyses of the PTClinResNet database: determining causal relationships among the International Classification of Functioning, Disability and Health levels for four physical therapy intervention trials.
        Phy Ther. 2011; 91: 1766-1779
        • Mahoney F.l.
        • Barthel D.W.
        Functional evaluation: the Barthel index.
        Md State Med J. 1965; 14: 61-68
        • Roy C.W.
        • Togneri J.
        • Hay E.
        • Pentland B.
        An inter-rater reliability study of the Barthel index.
        Int J Rehabil Res. 1988; 11: 67-70
        • Holbrook M.
        • Skilbeck C.E.
        An activities index for use with stroke patients.
        Age Ageing. 1983; 12: 166-170
        • Hsieh C.L.
        • Jang Y.
        • Yu T.Y.
        • Wang W.C.
        • Sheu C.F.
        • Wang Y.H.
        A Rasch analysis of the Frenchay Activities Index in patients with spinal cord injury.
        Spine. 2007; 32: 437-442
        • WHOQOL Group
        The World Health Organization quality of life assessment (WHOQOL): development and general psychometric properties.
        Soc Sci Med. 1998; 46: 1569-1585
        • Jang Y.
        • Hsieh C.L.
        • Wang Y.H.
        • Wu Y.H.
        A validity study of the WHOQOL-BREF assessment in persons with traumatic spinal cord injury.
        Arch Phys Med Rehabil. 2004; 85: 1890-1895
        • Chan S.C.
        • Chan A.P.
        User satisfaction, community participation and quality of life among Chinese wheelchair users with spinal cord injury: a preliminary study.
        Occup Ther Int. 2007; 14: 123-143
        • Brown M.
        • Dijkers M.P.
        • Gordon W.A.
        • Ashman T.
        • Charatz H.
        • Cheng Z.
        Participation objective, participation subjective: a measure of participation combining outsider and insider perspectives.
        J Head Trauma Rehabil. 2004; 19: 459-481
        • Price P.
        • Stephenson S.
        • Krantz L.
        • Ward K.
        Beyond my front door: the occupational and social participation of adults with spinal cord injury.
        OTJR. 2011; 31: 81-88
        • Myaskovsky L.
        • Burkitt K.H.
        • Lichy A.M.
        • et al.
        The association of race, cultural factors, and health-related quality of life in persons with spinal cord injury.
        Arch Phys Med Rehabil. 2011; 92: 441-448