Stroke Rehabilitation and Risk of Mortality: A Population-Based Cohort Study Stratified by Age and Gender

A Comparison of Rural and Urban Differences in Geographic Proximity to Outpatient Stroke Rehabilitation Services in Tennessee

PURPOSE

Great travel distances and long travel times can be barriers to outpatient stroke rehabilitation services (OSR) receipt, but there is limited information on differences in proximity to specific OSR services between urban and potentially medically underserved rural areas. Accordingly, we compared travel distance and time to the nearest service for different OSR services between rural and urban counties in Tennessee.

METHODS

We conducted data scraping on Google Maps to locate Tennessee facilities offering any of the 13 American Heart Association recognized OSR services. We conducted manual validation by calling located facilities and visiting facility websites. We used the Wilcoxon rank sum test to examine if mean travel distance and time to a specific OSR service differed significantly between rural and urban counties.

RESULTS

All OSR services but audiology were available in Tennessee. In rural counties, social work had the highest median of mean travel distance (135.2 km), chaplaincy the highest median of mean travel time (113.5 min), and physical therapy the lowest distance (37.7 km) and time (36.3 min). Except for social work, rural counties had significantly higher travel distance and time than urban counties (P < .01) for all OSR services.

CONCLUSIONS

Rural Tennessee counties had significantly higher travel distance and time for almost all OSR services compared to urban areas. These findings from a largely rural state with high stroke risk factor prevalence suggest that additional focus on establishing maximum travel limits for OSR are warranted to overcome transportation barriers to enhance post-stroke services access in similar areas.

Association Between Frequency of Rehabilitation Therapy and Long-Term Mortality After Stroke: A Nationwide Cohort Study

BACKGROUND

Previous studies have demonstrated conflicting results regarding the effects of rehabilitation therapy on poststroke mortality. We aimed to investigate the association between rehabilitation therapy, including both inpatient and outpatient treatment, within the first 6 months after stroke and long-term all-cause mortality in patients with stroke using the Korean National Health Insurance System data.

METHODS

A total of 10 974 patients newly diagnosed with stroke using the International Classification of Diseases, Tenth Revision, codes (I60-I64) between 2003 and 2019 were enrolled and followed up for all-cause mortality until 2019. Follow-up for mortality began 6 months after the index event. Poststroke patients were categorized into 3 groups according to the frequency of rehabilitation therapy: no rehabilitation therapy, ≤40 sessions and >40 sessions. Cox proportional hazards models were used to assess the mortality risk according to rehabilitation therapy stratified by disability severity measured based on activities of daily living 6 months after stroke onset.

RESULTS

Within 6 months after stroke, 6738 patients (61.4%) did not receive rehabilitation therapy, whereas 2122 (19.3%) received ≤40 sessions and 2114 (19.3%) received >40 sessions of rehabilitation therapy. Higher frequency of rehabilitation therapy was associated with significantly lower poststroke mortality in comparison to no rehabilitation therapy (hazard ratio [HR], 0.88 [95% CI, 0.79-0.99]), especially among individuals with severe disability after stroke (mild to moderate: HR, 1.02 [95% CI, 0.77-1.35]; severe: HR, 0.74 [95% CI, 0.62-0.87]). In the context of stroke type, higher frequency of rehabilitation therapy was associated with reduced mortality rates compared with no rehabilitation therapy only in patients with hemorrhagic stroke (ischemic: HR, 1.04 [95% CI, 0.91-1.18]; hemorrhagic: HR, 0.60 [95% CI, 0.49-0.74]).

CONCLUSIONS

We found a positive association between rehabilitation therapy within 6 months after stroke onset and long-term mortality in patients with stroke. A higher frequency of rehabilitation therapy would be recommended for poststroke patients, especially those with hemorrhagic stroke and severe disability.

Effect of the Frequency of Rehabilitation Treatments on the Long-Term Mortality of Stroke Survivors with Mild-to-Moderate Disabilities under the Korean National Health Insurance Service System

Given the increase in stroke-related social costs, studies on survival and functional prognosis after stroke are urgently needed. Therefore, we investigated the relationship between the frequency of rehabilitation treatments in the acute and subacute phases of stroke and the long-term mortality of stroke survivors with mild-to-moderate disabilities. We performed a retrospective cohort study using data from the Korean National Health Insurance Service database. Our final cohort included 733 patients with national disability registration grades 4-6. The number of special rehabilitation treatment claim codes was used as a proxy for the frequency of rehabilitation treatments. Furthermore, we categorized the rehabilitation frequencies within 24 months of stroke onset as 1-50, 51-200, 201-400, and >400. The dependent variable was all-cause mortality, and it was evaluated from 24 to 84 months after stroke onset. Severe disability was associated with a lower long-term mortality rate in the chronic phase (p < 0.001). In the Cox regression analysis, severe disability, older age, male sex, and chronic kidney disease were independent risk factors for long-term mortality in patients with stroke and mild-to-moderate disabilities. However, the frequency of acute/subacute rehabilitation treatments did not significantly improve long-term mortality. Our results suggest that the association between rehabilitation frequency and lower long-term mortality for patients with mild-to-moderate stroke was inconclusive. Therefore, further study is needed to determine a better-customized rehabilitation treatment system for these patients.

Chronic Phase Survival Rate in Stroke Patients With Severe Functional Limitations According to the Frequency of Rehabilitation Treatment

OBJECTIVE

To investigate the chronic phase survival rate according to the frequency of rehabilitation treatment in the acute and subacute phases in stroke patients with severe functional limitations.

DESIGN

A retrospective longitudinal cohort study.

SETTING

Population-based study using the Korean National Health Insurance Database from 2007 to 2018.

PARTICIPANTS

We enrolled 593 patients who experienced stroke in 2009 with national disability registration (NDR) grade of 3 or less (N=593).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The frequencies of rehabilitation treatment within 24 months after stroke were categorized into none, 1-50, 51-200, 201-400, and >400 treatments based on requests made to the Health Insurance Review and Assessment Service. As a dependent variable, we assessed all-cause mortality from 24 to 120 months after stroke.

RESULTS

The study enrolled 283 patients in NDR grade 1 (the most severe), 158 in grade 2, and 152 in grade 3. Groups with more severe functional limitations showed a lower chronic phase survival rate (P<.001). The groups with higher frequencies of rehabilitation treatment in the acute and subacute phases showed a higher chronic phase survival rate (P<.001). In the Cox regression analysis, a higher degree of functional limitation, lower frequency of rehabilitation treatment, older age, male sex, and chronic kidney disease were independent risk factors for chronic phase mortality in stroke patients with severe functional limitations.

CONCLUSIONS

A high frequency of rehabilitation treatment in the acute and subacute phases was associated with the long-term survival of stroke patients with severe functional limitations.

Observational Studies: Specific Considerations for the Physical and Rehabilitation Medicine Physician

ABSTRACT

The development of high-quality research is desired in all healthcare fields. Experimental and nonexperimental designs are used to investigate the effect or association of an intervention and clinical or surrogate outcome. The aims of these methods are to improve knowledge and to develop new strategies to manage a disease or condition. Randomized clinical trials are considered one of the standard methods to test the efficacy of a new drug or intervention; however, they are costly, have reduced generalizability, and cannot be feasible in all scenarios. Well-designed observational studies can provide valuable information regarding exposure factor and the event under investigation. In physical and rehabilitation medicine, where complex procedures and multiple risk factors can be involved in the same disease, the use of observational study must be planned in detail and a priori to avoid overestimations. In this article, we will give an overview of the methods used for observational design studies in physical and rehabilitation medicine using clinical examples to illustrate each method. We will describe when it is appropriate and how to use the observational studies in different scenarios explaining how to deal with potential bias and confounders using the adequate design and statistical plan for the situation.

Long-Term Rehabilitation Utilization Pattern Among Stroke Patients Under the National Health Insurance Program

OBJECTIVE

The aim of this study was to understand the frequency of patients receiving rehabilitation services at various periods after stroke and the possible medical barriers to receiving rehabilitation.

DESIGN

A retrospective cohort study was conducted using a nationally representative sample in Taiwan. A total of 14,600 stroke patients between 2005 and 2011 were included. Utilization of physical therapy or occupational therapy at different periods after stroke onset was the outcome variable. Individual and geographic characteristics were investigated to determine their effect on patients' probability of receiving rehabilitation.

RESULTS

More severe stroke or more comorbid diseases increased the odds of receiving physical therapy and occupational therapy; older age was associated with decreased odds. Notably, sex and stroke type influenced the odds of rehabilitation only in the early period. Copayment exemption lowered the odds of rehabilitation in the first 6 mos but increased the odds in later periods. Rural and suburban patients had significantly lower odds of receiving physical therapy and occupational therapy, as did patients living in areas with fewer rehabilitation therapists.

CONCLUSIONS

Besides personal factors, geographic factors such as urban-rural gaps and number of therapists were significantly associated with the utilization of post-stroke rehabilitation care. Furthermore, the influence of certain factors, such as sex, stroke type, and copayment exemption type, changed over time.

Machine learning to predict mortality after rehabilitation among patients with severe stroke

Stroke is among the leading causes of death and disability worldwide. Approximately 20–25% of stroke survivors present severe disability, which is associated with increased mortality risk. Prognostication is inherent in the process of clinical decision-making. Machine learning (ML) methods have gained increasing popularity in the setting of biomedical research. The aim of this study was twofold: assessing the performance of ML tree-based algorithms for predicting three-year mortality model in 1207 stroke patients with severe disability who completed rehabilitation and comparing the performance of ML algorithms to that of a standard logistic regression. The logistic regression model achieved an area under the Receiver Operating Characteristics curve (AUC) of 0.745 and was well calibrated. At the optimal risk threshold, the model had an accuracy of 75.7%, a positive predictive value (PPV) of 33.9%, and a negative predictive value (NPV) of 91.0%. The ML algorithm outperformed the logistic regression model through the implementation of synthetic minority oversampling technique and the Random Forests, achieving an AUC of 0.928 and an accuracy of 86.3%. The PPV was 84.6% and the NPV 87.5%. This study introduced a step forward in the creation of standardisable tools for predicting health outcomes in individuals affected by stroke.

Association between Clinical and Laboratory Markers and 5-year Mortality among Patients with Stroke

Factors influencing long-term stroke mortality have not been comprehensively investigated. This study aimed to identify the baseline clinical, laboratory, demographic/socioeconomic, and hospital factors influencing 5-year mortality in patients with first stroke. Total 3,956 patients with first-stroke hospitalization from 2004 to 2008 were connected to the longitudinal National Health Insurance Research Database. Post-admission baseline data that significantly increased 5-year mortality were red cell distribution width (RDW) >0.145 (adjusted hazard ratio [aHR] = 1.71), hemoglobin <120 g/L (aHR = 1.25), blood sugar <3.89 mmol/L (70 mg/dL)(aHR = 2.57), serum creatinine >112.27 μmol/L (aHR = 1.76), serum sodium <134 mmol/L (aHR = 1.73), body mass index (BMI) < 18.5 kg/m² (aHR = 1.33), Glasgow Coma Scale <15 (aHR = 1.43), Stroke Severity Index ≥20 (aHR = 3.92), Charlson–Deyo Comorbidity Index ≥3 (aHR = 4.21), no rehabilitation (aHR = 1.86), and age ≥65 years (aHR = 2.25). Hemoglobin, RDW, blood sugar, serum creatinine and sodium, BMI, consciousness, stroke severity, comorbidity, rehabilitation, and age were associated with 5-year mortality in patients with first stroke.

Effects of Transferring to the Rehabilitation Ward on Long-Term Mortality Rate of First-Time Stroke Survivors: A Population-Based Study

OBJECTIVE

To assess the long-term health outcomes of acute stroke survivors transferred to the rehabilitation ward.

DESIGN

Long-term mortality rates of first-time stroke survivors during hospitalization were compared among the following sets of patients: patients transferred to the rehabilitation ward, patients receiving rehabilitation without being transferred to the rehabilitation ward, and patients receiving no rehabilitation.

SETTING

Retrospective cohort study.

PARTICIPANTS

Patients (N = 11,419) with stroke from 2005 to 2008 were initially assessed for eligibility. After propensity score matching, 390 first-time stroke survivors were included.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

Cox proportional hazards regression model was used to assess differences in 5-year poststroke mortality rates.

RESULTS

Based on adjusted hazard ratios (HRs), the patients receiving rehabilitation without being transferred to the rehabilitation ward (adjusted HR, 2.20; 95% confidence interval [CI], 1.36-3.57) and patients receiving no rehabilitation (adjusted HR, 4.00; 95% CI, 2.55-6.27) had significantly higher mortality risk than the patients transferred to the rehabilitation ward. Mortality rate of the stroke survivors was affected by age ≥65 years (compared with age <45y; adjusted HR, 3.62), being a man (adjusted HR, 1.49), having ischemic stroke (adjusted HR, 1.55), stroke severity (Stroke Severity Index [SSI] score≥20, compared with SSI score<10; adjusted HR, 2.68), and comorbidity (Charlson-Deyo Comorbidity Index [CCI] score≥3, compared with CCI score=0; adjusted HR, 4.23).

CONCLUSIONS

First-time stroke survivors transferred to the rehabilitation ward had a 5-year mortality rate 2.2 times lower than those who received rehabilitation without transfer to the rehabilitation ward and 4 times lower than those who received no rehabilitation.

Validity of a stroke severity index for administrative claims data research: a retrospective cohort study

Background

Ascertaining stroke severity in claims data-based studies is difficult because clinical information is unavailable. We assessed the predictive validity of a claims-based stroke severity index (SSI) and determined whether it improves case-mix adjustment.

Methods

We analyzed patients with acute ischemic stroke (AIS) from hospital-based stroke registries linked with a nationwide claims database. We estimated the SSI according to patient claims data. Actual stroke severity measured with the National Institutes of Health Stroke Scale (NIHSS) and functional outcomes measured with the modified Rankin Scale (mRS) were retrieved from stroke registries. Predictive validity was tested by correlating SSI with mRS. Logistic regression models were used to predict mortality.

Results

The SSI correlated with mRS at 3 months (Spearman rho = 0.578; 95 % confidence interval [CI], 0.556–0.600), 6 months (rho = 0.551; 95 % CI, 0.528–0.574), and 1 year (rho = 0.532; 95 % CI 0.504–0.560). Mortality models with the SSI demonstrated superior discrimination to those without. The AUCs of models including the SSI and models with the NIHSS did not differ significantly.

Conclusions

The SSI correlated with functional outcomes after AIS and improved the case-mix adjustment of mortality models. It can act as a valid proxy for stroke severity in claims data-based studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-016-1769-8) contains supplementary material, which is available to authorized users.

Functional Gain After Inpatient Stroke Rehabilitation

Background and Purpose—

Prediction of functional outcome after stroke rehabilitation (SR) is a growing field of interest. The association between SR and survival still remains elusive. We sought to investigate the factors associated with functional outcome after SR and whether the magnitude of functional improvement achieved with rehabilitation is associated with long-term mortality risk.

Methods—

The study population consisted of 722 patients admitted for SR within 90 days of stroke onset, with an admission functional independence measure (FIM) score of <80 points. We used univariable and multivariable linear regression analyses to assess the association between baseline variables and FIM gain and univariable and multivariable Cox analyses to assess the association of FIM gain with long-term mortality.

Results—

Age ( P <0.001), marital status ( P =0.003), time from stroke onset to rehabilitation admission ( P <0.001), National Institutes of Health Stroke Scale score at rehabilitation admission ( P <0.001), and aphasia ( P =0.021) were independently associated with FIM gain. The R 2 of the model was 0.275. During a median follow-up of 6.17 years, 36.9% of the patients died. At multivariable Cox analysis, age ( P <0.0001), coronary heart disease ( P =0.018), atrial fibrillation ( P =0.042), total cholesterol ( P =0.015), and total FIM gain ( P <0.0001) were independently associated with mortality. The adjusted hazard ratio for death significantly decreased across tertiles of increasing FIM gain.

Conclusions—

Several factors are independently associated with functional gain after SR. Our findings strongly suggest that the magnitude of functional improvement is a powerful predictor of long-term mortality in patients admitted for SR.