Abstract
Objective
To examine, from a Canadian population-based perspective, the incidence and etiology of long-term hospital utilization among persons living with traumatic brain injury (TBI) by age and sex.
Design
Retrospective cohort study.
Setting
Acute care hospitals.
Participants
Index cases of TBI (N=29,269) were identified from the Discharge Abstract Database for fiscal years 2002/2003 through 2009/2010 and were followed-up until 36 months after injury.
Interventions
Not applicable.
Main Outcome Measures
Rehospitalization was defined as admission to an acute care facility that occurred up to 36 months after index injury. Diagnoses associated with subsequent rehospitalization were examined by age and sex.
Results
Of the patients with TBI, 35.5% (n=10,390) were subsequently hospitalized during the 3-year follow-up period. Multivariable logistic regression (controlling for index admission hospital) identified men, older age, mechanism of injury being a fall, greater injury severity, rural residence, greater comorbidity, and psychiatric comorbidity to be significant predictors of rehospitalization in a 3-year period postinjury. The most common causes for rehospitalization differed by age and sex.
Conclusions
Rehospitalization after TBI is common. Factors associated with rehospitalization can inform long-term postdischarge planning. Findings also support examining causes for rehospitalization by age and sex.
Keywords
List of abbreviations:
ADG (Aggregated Diagnosis Group), DAD (Discharge Abstract Database), ICD-10-CA (International Classification of Diseases–10th Revision–Canadian Enhancement), MVC (motor vehicle collision), TBI (traumatic brain injury)Traumatic brain injury (TBI) is a major cause of death and disability in the United States. Approximately 1.7 million people will sustain a TBI each year in the United States, resulting in 1.4 million emergency department visits, 275,000 hospitalizations, and 52,000 deaths.
1
The economic costs associated with TBI, including direct medical and rehabilitation costs and indirect societal costs, are estimated to be $60 billion in the United States.2
Recurrence of hospitalization (ie, rehospitalization) is a common problem among individuals with a chronic condition or injury and is associated with increased health care costs and reduced health care quality.
3
, 4
, 5
A reported 15% of individuals with chronic conditions (eg, stroke, TBI, hip fracture) were readmitted to hospital within 2 months after discharge.6
Those who suffered from an injury had an increased risk of reinjury.7
Older age, being a man, greater injury severity,7
, 8
and longer initial length of stay9
, 10
were associated with higher rates of readmission, with most readmissions being the result of congestive heart failure and chronic obstructive pulmonary disease.9
, 11
These trends, however, apply to a diverse population with various conditions and may not necessarily generalize to patients with a TBI.Persons with TBI have higher rates of readmission and are more likely to incur subsequent injuries compared with nonbrain injured controls, with numbers ranging from 16% to 18% at 6 months,
12
, 13
17% to 20% at 1 year,13
, 14
and 20% to 23% over a 3-year period.15
Similar rates of rehospitalization have been established at 5 years postinjury, with a trend toward elective surgery early on and general health maintenance after the first year.16
Children and adults who sustained a TBI also appear more likely to sustain another injury at 1- and 10-year follow-up, respectively, compared with nonbrain injured controls.17
, 18
Previous studies, however, have examined patients with TBI who were discharged from selected trauma
12
, 13
or rehabilitation centers,14
, 15
, 16
which predominately treat a small segment of moderate to severe cases and are likely affected by attrition.12
, 13
, 14
, 15
, 16
, 19
A subset of these studies was based on U.S. data,15
, 16
and those conducted in Canada are limited to a specific age group17
, 18
or include only unplanned readmissions.12
, 13
Consequently, the aim of the current study was to investigate, from a Canadian population-based perspective, the incidence and etiology of all rehospitalizations among those who sustained a TBI at 1- and 3-year follow-up times. Given that the incidence rates of TBI vary by age and sex,19
, 20
rehospitalization rates were stratified by these factors.Methods
Participants
Participants included in this retrospective cohort study were patients discharged alive from Ontario hospitals between April 1, 2003, and March 31, 2010 (fiscal years 2002/2003–2009/2010) for a TBI. Patients with a TBI were identified from acute care hospitalization records using the following International Classification of Diseases–10th Revision–Canadian Enhancement (ICD-10-CA) injury codes: a fracture of the skull and facial bones (S02.0, S02.1, S02.3, S02.7, S02.8, S02.9), injury to the optic nerve and pathways (S04.0), intracranial injury (S06.0–S06.9), or crushing injury of the head (S07.0–S07.9). To ensure integrity of the incident cases, patients were excluded from analyses if they sustained a TBI the year prior to their index injury. A 1-year clearance is consistent with prior studies that investigate readmissions after injury.
8
, 17
Further exclusion criteria included patients who died in hospital from the index TBI, patients who resided outside of Ontario, and patients whose records contained unspecified sex information or erroneously recorded date of death. Ethics approval was received from the Toronto Rehabilitation Institute and Institute for Clinical Evaluative Sciences.Data sources
Hospital admission data were accessed at the Institute for Clinical Evaluative Sciences using the Canadian Institute of Health Information Discharge Abstract Database (DAD),
21
which contains information on the following variables: age, sex, residential postal code, date of admission, date of discharge, primary ICD diagnostic codes, and secondary and tertiary ICD diagnostic codes. Index cases of TBI were identified from the DAD using data from 141 hospitals (ranging in size from 1 to 2743 patients being treated per institution). Excellent agreement for primary diagnoses has been found between administrative hospitalization data and chart audit.22
The Registered Persons Database was used to identify mortality information of participants. It contains the date of birth and cause and date of death of all persons with a valid Ontario Health Card. Patients were linked via unique encoded identifiers and analyzed at the Institute for Clinical Evaluative Sciences (100% match).Variables
Information was extracted from the DAD and Registered Persons Database and categorized based on preinjury, injury, and postinjury study variables.
Preinjury variables
Demographic information (eg, age at the time of initial injury, sex, rurality) was collected. Age was divided into 5 groups: children (<15y), adolescents/young adults (15–24y), adults (25–49y, 50–64y), and seniors (>65y). Rural versus nonrural residence was determined using postal codes from administrative databases.
23
Injury variables
Variables collected at the time of injury included mechanism of injury, Abbreviated Injury Score,
24
initial length of acute care stay based on the duration of the index hospitalization, comorbidity, and psychiatric comorbidity. The mechanisms of injury were identified using injury codes and grouped into 4 major categories: falls, motor vehicle collision (MVC), struck by/against, and other mechanism of injury. Discharge destination was also examined to describe the cohort. In Ontario, patients may be discharged to another facility, transferred to long-term care or ambulatory/palliative care, or discharged home with or without services. Rehabilitation can occur in acute care hospitals and/or at freestanding inpatient rehabilitation hospitals. Year of injury was added to multivariable models to control for practice changes over time.The Abbreviated Injury Score was used as a measure of TBI severity. Severity was measured on a 6-point scale and categorized as mild (1–2), moderate (3), or severe (≥4) injury. If a patient had >1 diagnosis of TBI on their hospital record, the injury with the highest severity was used to classify the severity. The Johns Hopkins Adjusted Clinical Group Case-Mix System was used to account for patient comorbidity.
25
, 26
, 27
This method of adjusting for case mix has previously been used in Canada28
and has been validated in the United States.29
The system uses individual-level data to assign measures of resource use and comorbidity from diagnoses during a specified time period, obtained from patient records. In the present study, the Adjusted Clinical Group algorithm used physician billing claims from the Ontario Health Insurance Plan administrative database and hospital admissions from 2 years prior to index to determine a comorbidity score for patients equal to the sum of the Aggregated Diagnosis Group (ADG) indicators. Psychiatric comorbidities were additionally examined as a separate variable.Outcome variables
Transfers between facilities for the incident TBI were censored to minimize the potential for misclassifying readmissions. Therefore, for this analysis, patients with incident TBI between fiscal years 2002/2003 and 2009/2010 were followed-up from 4 days after the initial acute care discharge until March 31, 2013, to identify readmission to an acute care facility for a hospital stay. Emergency department visits were not included as a hospital admission; however, a 1-night admission was included as an outcome variable. Participants were followed from index injury up to a maximum of 36 months. ICD-10-CA codes at admission were examined to identify causes of hospitalization and categorized according to ICD-10-CA chapter headings.
Data analyses
Descriptive statistics of patient characteristics at time of index injury were stratified by age and sex. Rehospitalization rates were also stratified based on duration since index injury (1 vs 3y post-TBI). A multivariable logistic regression model was run using a backward entry method to determine which variables contributed to the prediction of rehospitalization rates at 1 year and 3 years. Rehospitalization because of pregnancy/childbirth was not included in the model because this was not considered a negative health event. The models were fit using a generalized estimating equation (autoregressive correlation structure) to account for the correlation between rehospitalization and index admission hospital (n=138; 3 hospitals had patients with only maternity outcomes). Adjusting by index hospital allowed for any undue influence related to the admission hospital (eg, common patient characteristics attending certain hospitals, differences in hospitals practices) to be covaried out of the models. Initial length of acute care stay was excluded from the model based on poor fit as determined by Hosmer-Lemeshow goodness of fit test. The Abbreviated Injury Score was the only measure of severity entered into the analyses. ADG was entered as a continuous and quadratic variable. Although the interaction term between age and sex was entered for both the 1-year and 3-year models, it was not significant and therefore was excluded from both analyses. A P value ≤.05 was considered statistically significant. Analyses were performed using SAS version 9.3.a
Results
Descriptive statistics
There were 29,269 patients with TBI identified from the DAD records between fiscal years 2002/2003 through 2009/2010. Most patients with TBI were men (table 1). Falls were the most common mechanism of injury for patients <15 and >49 years of age, whereas patients between 15 and 49 years were, on average, more likely to sustain a TBI because of a MVC. Patterns were similar across men and women, with the exception that among the 25- to 49-year-old age group, falls and MVC were the most common mechanisms of injury for men and women, respectively. The percentage of severely injured patients increased by age, as did the number of comorbid conditions. Most patients had no psychiatric comorbidity (96.5%) and lived in a nonrural setting (83.9%).
Table 1Patient characteristics at index time of injury stratified by age and sex (%)
| Characteristic | <15y | 15–24y | 25–49y | 50–64y | ≥65y | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| M (n=2637) | F (n=1501) | M (n=3453) | F (n=935) | M (n=5039) | F (n=1616) | M (n=3064) | F (n=1273) | M (n=5062) | F (n=4689) | |
| Rurality | ||||||||||
| Rural | 16.7 | 15.3 | 19.5 | 21.6 | 16.6 | 18.3 | 16.6 | 18.0 | 14.2 | 11.4 |
| Nonrural | 83.2 | 84.5 | 80.5 | 78.4 | 83.2 | 81.7 | 83.3 | 81.9 | 85.6 | 88.5 |
| Unknown | 0.1 | 0.1 | 0.0 | 0.0 | 0.2 | 0.1 | 0.1 | 0.2 | 0.1 | 0.1 |
| ADG comorbidity | ||||||||||
| 0–3 | 42.3 | 40.4 | 45.2 | 25.9 | 33.8 | 19.2 | 22.2 | 13.7 | 6.7 | 5.5 |
| 4–5 | 33.5 | 32.6 | 31.7 | 29.6 | 30.4 | 25.5 | 24.8 | 21.8 | 15.8 | 16.7 |
| 6–7 | 15.2 | 17.8 | 15.1 | 24.7 | 18.9 | 26.4 | 22.7 | 23.0 | 21.6 | 23.4 |
| 8–9 | 6.1 | 6.1 | 5.8 | 11.7 | 10.0 | 15.7 | 15.6 | 20.0 | 21.8 | 21.3 |
| ≥10 | 2.8 | 3.0 | 2.2 | 8.1 | 6.8 | 13.2 | 14.8 | 21.5 | 34.2 | 33.0 |
| Psychiatric comorbidity | ||||||||||
| Yes | 0.3 | 0.1 | 1.0 | 2.1 | 3.4 | 4.7 | 4.8 | 4.6 | 5.0 | 5.7 |
| Mechanism of injury | ||||||||||
| MVC | 12.9 | 13.3 | 34.9 | 56.7 | 25.4 | 40.1 | 18.3 | 26.7 | 9.4 | 8.5 |
| Fall | 47.4 | 56.9 | 15.3 | 15.1 | 26.7 | 30.3 | 51.5 | 56.7 | 77.6 | 84.6 |
| Struck by/against | 19.2 | 14.1 | 29.8 | 12.1 | 25.4 | 11.8 | 12.6 | 5.3 | 3.6 | 1.9 |
| Other | 19.8 | 15.1 | 19.0 | 15.5 | 21.4 | 17.0 | 16.3 | 10.0 | 8.0 | 3.2 |
| Missing | 0.8 | 0.5 | 0.9 | 0.6 | 1.1 | 0.9 | 1.3 | 1.3 | 1.4 | 1.7 |
| Abbreviated Injury Scale | ||||||||||
| Mild (1–2) | 50.1 | 53.0 | 37.4 | 38.1 | 31.1 | 32.1 | 21.7 | 27.4 | 13.2 | 17.8 |
| Moderate (3) | 5.3 | 5.6 | 10.6 | 9.2 | 14.1 | 14.5 | 13.0 | 13.4 | 10.5 | 13.1 |
| Severe (≥4) | 37.9 | 34.0 | 47.7 | 47.3 | 49.8 | 47.7 | 60.1 | 53.1 | 71.9 | 63.5 |
| Unknown | 6.7 | 7.3 | 4.3 | 5.5 | 4.9 | 5.7 | 5.2 | 6.1 | 4.3 | 5.6 |
| Length of stay (d) | ||||||||||
| 1–2 | 71.3 | 72.5 | 49.3 | 39.1 | 38.9 | 38.2 | 31.3 | 33.1 | 21.6 | 19.3 |
| 3–5 | 15.8 | 15.3 | 20.7 | 20.0 | 21.9 | 20.0 | 22.6 | 22.4 | 22.1 | 20.7 |
| 6–11 | 6.2 | 6.3 | 12.3 | 17.4 | 16.6 | 17.1 | 18.3 | 20.6 | 22.6 | 23.7 |
| ≥12 | 6.8 | 5.9 | 17.8 | 23.4 | 22.6 | 24.6 | 27.8 | 24.0 | 33.7 | 36.3 |
| Discharge destination | ||||||||||
| Transferred to another facility | 3.7 | 2.9 | 8.5 | 12.5 | 12.5 | 12.6 | 14.5 | 14.0 | 18.3 | 14.4 |
| Transferred to long-term care | 1.2 | 1.1 | 5.4 | 6.3 | 7.5 | 9.5 | 11 | 10.7 | 21.2 | 28.0 |
| Transferred to ambulatory care/palliative | 1.6 | 1.4 | 1.9 | 2.8 | 3.0 | 2.5 | 2.9 | 2.1 | 2.5 | 2.2 |
| Discharged home with services | 5.5 | 4.1 | 5.6 | 7.7 | 5.9 | 6.6 | 7.3 | 9.0 | 13.8 | 19.7 |
| Discharged home without services | 87.9 | 90.3 | 77.3 | 70.3 | 67.7 | 67.1 | 61.9 | 63.1 | 43.8 | 35.3 |
Abbreviations: F, female; M, male.
Of the 29,269 patients with TBI, 22.9% (n=6703) were rehospitalized within 1 year, and 35.5% (n=10,390) were rehospitalized within the 3 years after index injury. As seen in table 2, percentages of rehospitalization increased steadily by age group. Although there were no sex differences in the number of rehospitalizations at 1 year, women between the ages of 15 and 49 years had a near 15% increase in the number of rehospitalizations relative to men at 3-years follow-up. Overall, the diagnoses most often reported at the time of rehospitalization were in the injury/poisoning ICD category. Poisoning is defined as a drug overdose (eg, poisoning by systemic antibodies, poisoning by other systemic anti-infectives and antiparasitics, poisoning by anesthetics and therapeutic gas). These were not intentional self-poisonings that would have resulted from an attempted suicide.
Table 2Rehospitalization within 1 and 3 years from index TBI, stratified by age and sex (%)
| Follow-up Period | <15y | 15–24y | 25–49y | 50–64y | ≥65y | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| M (n=2637) | F (n=1501) | M (n=3453) | F (n=935) | M (n=5039) | F (n=1616) | M (n=3064) | F (n=1273) | M (n=5062) | F (n=4689) | |
| Hospitalization within 1y (%) | 7.8 | 6.3 | 11.8 | 14.0 | 17.9 | 21.6 | 24.6 | 24.3 | 37.3 | 35.1 |
| Hospitalization within 3y (%) | 12.9 | 11.1 | 18.4 | 28.6 | 27.1 | 35.9 | 38.0 | 38.3 | 56.1 | 54.3 |
When stratified by age and sex, differences were observed in the causes of rehospitalization (table 3). Under the age of 15 years, boys were most likely to be readmitted because of injury/poisoning (χ21,909=3.13, P=.077), and girls were most likely to be readmitted for health status related to follow-up care (χ21,909=20.26, P<.001). Cause of rehospitalization for patients aged 15 to 24 years also varied by sex: for women, the main cause was pregnancy, childbirth, and puerperium, followed by injuries, poisoning, and other external causes; for men, the main cause was injuries, poisoning, and other external causes (χ21,1475=38.15, P<.001), followed by disorders of the musculoskeletal system or health status (P=.555). The main causes of rehospitalization for patients aged 25 to 49 years were injury/poisoning, followed by mental and behavioral disorders for men (χ21,4121=4.66, P=.031) and digestive disorders for women (χ21,4121=3.92, P=.048). For those 50 to 64 years of age, the most common cause of rehospitalization for both sexes was injury/poisoning, followed by circulatory complaints for men (χ21,3755=7.6, P=.006) and digestive complaints for women (χ21,3755=2.91, P=.088). Over the age of 64 years, circulatory problems were the most common cause for both men and women.
Table 3Causes of rehospitalization based on ICD-10 codes, stratified by age and sex (%)
| Reason for Rehospitalization | <15y | 15–24y | 25–49y | 50–64y | ≥65y | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| M (n=610) | F (n=299) | M (n=1010) | F (n=465) | M (n=2838) | F (n=1283) | M (n=2619) | F (n=1136) | M (n=6183) | F (n=5173) | |
| Injury/poisoning | 19.5 | 14.7 | 31.7 | 16.3 | 25 | 17.4 | 16.8 | 17.3 | 12.8 | 15.5 |
| Digestive system | 9 | 7.7 | 7.3 | 9 | 8.5 | 10.4 | 10.3 | 12.2 | 8 | 8.8 |
| Abnormal findings | 10.7 | 11.4 | 5.9 | 5.8 | 7.2 | 9 | 9.5 | 8.5 | 9.5 | 10.8 |
| Health status | 9 | 16.1 | 11.6 | 11.8 | 7.5 | 7.1 | 6.8 | 5.4 | 6.8 | 6.7 |
| Respiratory | 16.2 | 15.4 | 4.4 | <2 | 4.4 | 5 | 7.1 | 8 | 11.9 | 10.8 |
| Circulatory | 2 | <2 | 1.8 | 1.5 | 4.2 | 3.7 | 11.8 | 8.7 | 21.6 | 19.2 |
| Musculoskeletal | 5.9 | 5 | 11.6 | 10.5 | 10.9 | 7.1 | 6.8 | 7.7 | 3.5 | 3.6 |
| Mental/behavioral | 3.3 | 4.3 | 8.1 | 4.1 | 11.9 | 9.6 | 8.1 | 7.3 | 3.3 | 3 |
| Nervous system | 7.5 | 3.7 | 7.2 | 2.2 | 7.5 | 5.5 | 5.7 | 4 | 3.8 | 2.7 |
| Pregnancy/childbirth | 0 | <2 | 0 | 26.7 | 0 | 9 | 0 | 0 | 0 | 0 |
| Genitourinary system | 2 | <2 | 2.5 | 2.2 | 2 | 5.5 | 3.9 | 4.5 | 6 | 6.3 |
| Neoplasms | 1 | 5 | 0.9 | <2 | 1.5 | 2.8 | 4.5 | 5.2 | 4.9 | 3.3 |
| Infectious/parasitic | 4.6 | 6 | 1.5 | <2 | 2.2 | 1.8 | 2.3 | 2.7 | 3 | 3.2 |
| Endocrine/nutritional/metabolic | 1.8 | <2 | 1.6 | 3.4 | 2.6 | 2.3 | 3.7 | 4.8 | 2.9 | 3.8 |
| Other | 7.7 | 6.1 | 4 | 4 | 4.7 | 3.8 | 2.8 | 3.7 | 1.9 | 2.4 |
NOTE. Data were missing or invalid for <6 rehospitalizations. All other causes of rehospitalizations have been classified.
Abbreviation: ICD-10-CA, International Classification of Diseases–10th Revision–Canadian Enhancement.
∗ Related to follow-up care/convalescence.
† Causes that represented <4% of hospitalizations per age/sex group were collapsed into an other category.
Predictors of rehospitalization
Multivariable logistic regression analysis using the number of rehospitalizations at 1 year, while controlling for index admission hospital, demonstrated that being a man, older age, greater injury severity, suffering from an unknown mechanism of injury, and ADG and psychiatric comorbidity were significant predictors of rehospitalization, whereas persons who were struck by or against or had a later year of index injury (2006–2008) were less likely to be hospitalized (table 4). An odds ratio for ADG was not reported given the quadratic nature of the variable. There was a trend for those with a fall to have a greater risk of rehospitalization. Similar risk factors were found at 3 years: age, sex, mechanism of injury, comorbidity, and later year of index injury. Although most predictors were similar to those that were found at 1 year, being stuck by or against and unknown mechanism of injury were no longer significant predictors. Additional variables that contributed to the 3-year model were falls and rural dwelling (table 5).
Table 4Multivariable logistic regression analysis of predictors of rehospitalization within 1-year postindex injury (N=27,696)
| Variable | OR | 95% CI | P |
|---|---|---|---|
| Female (vs male) | 0.89 | 0.83–0.95 | <.001 |
| Age 15–24y (vs <15y) | 1.75 | 1.48–2.06 | <.001 |
| Age 25–49y (vs <15y) | 2.49 | 2.16–2.87 | <.001 |
| Age 50–64y (vs <15y) | 2.91 | 2.56–3.30 | <.001 |
| Age ≥65y (vs <15y) | 3.90 | 3.43–4.44 | <.001 |
| Rural (yes vs no) | 1.07 | 0.94–1.22 | .300 |
| No. of ADG | ND | ND | <.001 |
| No. of ADG squared | ND | ND | <.001 |
| Psychiatric comorbidity (vs none) | 1.70 | 1.48–1.96 | <.001 |
| Fall (vs MVC) | 1.12 | 1.00–1.25 | .056 |
| Struck by/against (vs MVC) | 0.84 | 0.73–0.97 | .014 |
| Other (vs MVC) | 0.99 | 0.92–1.07 | .865 |
| Unknown mechanism (vs MVC) | 1.45 | 1.14–1.86 | .003 |
| Injury severity moderate (vs mild) | 1.05 | 0.94–1.17 | .374 |
| Injury severity severe (vs mild) | 1.19 | 1.10–1.29 | <.001 |
| Year 2004 (vs 2003) | 0.92 | 0.85–1.01 | .071 |
| Year 2005 (vs 2003) | 0.89 | 0.79–1.01 | .072 |
| Year 2006 (vs 2003) | 0.87 | 0.78–0.98 | .023 |
| Year 2007 (vs 2003) | 0.87 | 0.78–0.97 | .013 |
| Year 2008 (vs 2003) | 0.93 | 0.86–1.00 | .045 |
| Year 2009 (vs 2003) | 0.93 | 0.82–1.06 | .263 |
Abbreviations: CI, confidence interval; ND, not done; OR, odds ratio.
∗ Autoregressive generalized estimating equation was used to control for index admission hospital.
Table 5Multivariable logistic regression analysis of predictors of rehospitalization within 3 years postindex injury (N=27,696)
| Variable | OR | 95% CI | P |
|---|---|---|---|
| Female (vs male) | 0.91 | 0.85–0.96 | .002 |
| Age 15–24y (vs <15y) | 1.66 | 1.50–1.84 | <.001 |
| Age 25–49y (vs <15y) | 2.45 | 2.20–2.73 | <.001 |
| Age 50–64y (vs <15y) | 3.19 | 2.87–3.54 | <.001 |
| Age ≥65 (vs <15y) | 4.99 | 4.58–5.45 | <.001 |
| Rural (yes vs no) | 1.11 | 1.03–1.20 | .006 |
| No. of ADG | ND | ND | <.001 |
| No. of ADG squared | ND | ND | <.001 |
| Psychiatric comorbidity (vs none) | 1.70 | 1.44–2.01 | <.001 |
| Fall (vs MVC) | 1.12 | 1.01–1.24 | .033 |
| Struck by/against (vs MVC) | 0.91 | 0.81–1.04 | .160 |
| Other (vs MVC) | 0.99 | 0.93–1.06 | .846 |
| Unknown mechanism (vs MVC) | 1.20 | 0.93–1.56 | .158 |
| Injury severity moderate (vs mild) | 1.08 | 0.98–1.18 | .131 |
| Injury severity severe (vs mild) | 1.09 | 1.02–1.17 | .012 |
| Year 2004 (vs 2003) | 0.92 | 0.84–1.01 | .074 |
| Year 2005 (vs 2003) | 0.86 | 0.77–0.95 | .005 |
| Year 2006 (vs 2003) | 0.85 | 0.78–0.93 | .001 |
| Year 2007 (vs 2003) | 0.87 | 0.80–0.95 | .001 |
| Year 2008 (vs 2003) | 0.93 | 0.84–1.02 | .123 |
| Year 2009 (vs 2003) | 0.94 | 0.85–1.05 | .258 |
Abbreviations: CI, confidence interval; ND, not done; OR, odds ratio.
∗ Autoregressive generalized estimating equation was used to control for index admission hospital.
Discussion
Our results demonstrate that rehospitalizations are common among men and women after a TBI. Approximately 35.5% of patients were rehospitalized within the first 3 years after a TBI, resulting in 10,390 patients being rehospitalized. Common causes of rehospitalization varied by age group and sex, which highlights the importance of examining the causes of rehospitalization based on these factors. Risk factors for rehospitalization at both 1- and 3-year post-TBI were sex, age, mechanism of injury, injury severity, and general and psychiatric comorbidity. These findings provide a valuable framework for the development of targeted intervention programs for those at greatest risk for recurrent hospitalization after TBI.
The rate of rehospitalization for patients with TBI in the present study was higher than previously reported rates of 16% to 23%.
12
, 13
, 14
, 15
, 16
This might be because all hospitalizations could be effectively tracked within a publicly insured population. These rates are also consistent with rehospitalization rates for patients with spinal cord injury at 1-year postinjury based on data from the same database.30
Contrary to other trauma patients readmitted to hospital as a result of infection,6
, 31
congestive heart failure, or chronic obstructive pulmonary disease,9
, 11
the sample in this study was more likely to be rehospitalized because of injury/poisoning. This is consistent with other studies that found that both adults17
and children18
with a TBI were more likely to suffer from a subsequent injury. Persons who sustain a TBI often report fatigue and dizziness,32
and these conditions could make them more prone to injury than other patient populations. The likelihood of reinjury accentuates the importance of targeting injury prevention programs for patients with TBI and additionally suggests that return to work or play could require greater long-term monitoring.Stratification of data by age and sex revealed important differences in the causes of rehospitalization. For instance, those <15 years old were more likely to be rehospitalized for diseases of the respiratory system, whereas those >64 years were more likely to be rehospitalized for diseases of the circulatory system. This is consistent with findings in the general population that circulatory problems are associated with older age.
33
Women of childbearing years presented with a high number of hospitalizations related to pregnancy and childbirth. This indicates the extent to which women have children after TBI and further demonstrates the importance of clarifying the cause of rehospitalization. Between the ages of 15 and 49 years, men were often rehospitalized for musculoskeletal problems, and women were often rehospitalized for digestive problems. Adults <65 years also had a notable number of rehospitalizations for mental health and behavioral disorders. This information is important for prevention efforts and demonstrates the need for intervention programs tailored to specific age groups and sexes.Overall, the results indicate that the risk of rehospitalization increased with being a man, older age, greater injury severity, sustaining a TBI because of a fall, and having additional physical or mental health conditions. The interaction between age and sex was not significant at 1-year or 3-year follow-up. Age
6
, 34
and longer initial length of acute care stay9
, 10
are well-known determinants of rehospitalization. Consistent with previous studies, being a woman is protective against rehospitalization.8
, 13
Lack of adequate services/supports in rural areas may contribute to the increased number of readmissions among these residents. Nonetheless, these results must be interpreted with caution given that the odds ratio for rural versus nonrural dwelling was close to 1 at 3-year follow-up and was nonsignificant at 1-year follow-up. Previous research has also indicated that mental health conditions are among the most prevalent comorbidities found with TBI.35
Patients discharged from acute care hospitals with mental health conditions were found to have a higher rate of readmission than patients discharged without these conditions11
, 36
; as such, comorbidity, and more specifically psychiatric comorbidity, seen in the present study may be an important risk factor for rehospitalization.Relative to falls and other mechanisms of injury, the risk of rehospitalization was reduced if a person was involved in a MVC, controlling for age and injury severity. In Ontario, persons injured in a MVC might be eligible for supplemental medical benefits through mandatory automobile insurance; such benefits include case management and community-based services, which are not publicly funded to the same degree. An Ontario study by Kim et al
37
showed that persons with a TBI injured by a MVC were 56% more likely to be discharged home with support services than patients who sustained at TBI from other causes, after controlling for age, severity of injury, and comorbidities. The additional support may have potentially aided recovery and therefore prevented subsequent injuries for MVC patients, limiting the number of rehospitalizations.Study limitations
A number of study limitations exist. First, the DAD does not include records of Ontario residents who sustained a TBI outside of the province, who were hospitalized outside of Ontario, who died prior to being taken to an emergency department or admitted to hospital, or who were treated for a TBI in physician offices or prisons. Another limitation of using administrative data is the possibility that a TBI diagnosis may be missed and that certain factors that capture severity (eg, Glasgow Coma Score), which are not mandatory to report, may be underreported. This could result in underestimates of rehospitalization after TBI. Patients with unknown injury severity were also excluded from the multivariable analysis; although this was a limitation in our study, the number missed represented only 5% of the cohort. Another limitation was the difficulty determining whether the rehospitalization had to do with a consequence of the index injury, whereby a TBI diagnostic code would be included in the discharge abstract, or because it was a new TBI. Nevertheless, the primary purpose of our investigation was to determine the long-term hospital utilization of patients with a TBI diagnosis and not specifically to examine reinjury.
Conclusions
Our findings demonstrate that the rates of rehospitalization after a TBI are higher than previously reported and that a number of factors can increase the risk of being rehospitalized. Prevention efforts for reinjury and mental health issues are important for the TBI population. The study also suggests that persons with access to more services are less likely to be hospitalized, supporting the need for better postacute care across geographic areas. In addition, greater support is needed for more vulnerable persons, particularly those living with mental health issues, which should be tailored by age and sex. Future work should seek to identify rehospitalization risk using other health care services after TBI (eg, emergency departments, outpatient facilities) and address the causes of reinjury using a longitudinal approach.
Supplier
- a.SAS version 9.3; SAS Institute.
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Article Info
Publication History
Published online: May 03, 2015
Footnotes
Supported by the Ontario Neurotrauma Foundation (grant no. 2006-ABI-RTBI-432 ); Ontario Neurotrauma Foundation-Réseau provincial de recherche en adaptation-réadaptation (grant no. ONF-2011-ONF-REPAR2-883 ); the Toronto Rehabilitation Institute ; the Institute for Clinical Evaluative Sciences , which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care ; and a Canadian Institutes of Health Research Research Chair in Gender, Work and Health (grant no. CGW-126580 ) from the Institute of Gender and Health.
The opinions, results, and conclusions reported in this article are those of the authors and are independent from the funding sources. No endorsement by the Institute for Clinical Evaluative Sciences or the Ontario Ministry of Health and Long-Term Care is intended or should be inferred.
Publication of this article was supported by the American Congress of Rehabilitation Medicine.
Disclosures: none.
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Copyright
© 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
