Prevalence of Walking Limitation After Acute Stroke and Its Impact on Discharge to Home

Louie DR, Simpson L, Mortenson WB, Field TS, Yao J, Eng JJ. Prevalence of walking limitation after acute stroke and its impact on discharge to home. Physical Therapy. 2021;102(1). doi:10.1093/ptj/pzab246

Link to Original Article: https://academic.oup.com/ptj/article/102/1/pzab246/6408936

Key Points

1. The study aimed to provide contemporary estimates of the prevalence of lower extremity motor impairment and walking limitation in patients hospitalized with a first-ever stroke and to assess the predictive nature of early walking ability for being discharged home after acute hospitalization.

2. The prevalence of lower extremity motor impairment was found to be 44.1%, and 46.0% to 57.9% of patients were unable to walk without varying levels of physical assistance within the first 3 to 5 days of stroke.

3. The study revealed that approximately one-half of patients experiencing a first-ever stroke present with lower extremity weakness and walking limitations and that early walking ability is a significant predictor of returning home after acute hospitalization, independent of stroke severity.

4. The logistic regression analyses indicated that early walking ability was independently predictive of being discharged home after acute hospitalization, with odds of 9.48 times greater for those with any ability to walk at admission compared to those who were unable, and 2.07 times greater odds for each increment on a 6-point walking scale.

5. The study emphasized the importance of walking at the beginning of the overall trajectory of stroke recovery and suggested that an assessment of walking function within days of stroke admission can facilitate discharge planning.

6. The prevalence findings in the study were slightly lower for lower extremity motor impairment and walking limitation compared to previous studies, possibly due to the exclusion of patients who died from stroke or experienced recurrent stroke.

Introduction

The study acknowledges stroke as a second leading cause of adult mortality and disability worldwide, often leading to lower extremity weakness and walking limitations. The ability to walk post-stroke is crucial for functional independence, community mobility, and quality of life. A prevalence update of lower extremity motor impairment and walking limitation is needed due to changing trends in stroke mortality and disability. The Copenhagen Stroke Study, which is one of the most frequently cited population studies, was conducted over 20 years ago. Since then, there has been a reported downward trend in stroke mortality and disability. This can be attributed to several factors, such as earlier detection, improved medical care, and an increasing incidence in young adults. The study aims to estimate the prevalence and understand their impact on discharge outcomes. The researchers hypothesized that 40-50% of stroke patients would experience walking limitations immediately after stroke, significantly impacting their discharge outcome. Additionally, early walking ability is predicted to be associated with being discharged home after acute hospitalization. The study aims to provide contemporary estimates of the prevalence of lower extremity motor impairment and walking limitation after stroke, with a focus on differences between patients who can walk immediately after stroke and those who cannot. It also seeks to explore the predictive nature of early walking ability for being discharged home after acute hospitalization.

Methods

The observational study utilized a convenience sample consisting of screening data from a longitudinal cohort study focusing on stroke recovery. Ethics and operational approval were obtained from the local university and hospital review board. Informed consent requirement was waived due to subsequent ethical approval for retrospective data collection. The analysis of the study was reported in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines, ensuring adherence to established reporting standards.

Participants

The study conducted at Vancouver General Hospital in British Columbia, Canada, aimed to investigate the prevalence of lower extremity motor impairment and limitations in walking ability following first-ever stroke, with a specific focus on differences between patients who were able to walk immediately after the stroke and those who were not. The participants in the study were individuals admitted to the stroke unit of the hospital between February 28, 2016, and August 31, 2017. This quaternary hospital serves a population of approximately 2.8 million people and is one of only 2 comprehensive stroke centers in the province, frequently receiving patients transferred from other areas for a higher level of care.

The inclusion criteria for the study comprised individuals over 18 years of age who experienced a first-ever ischemic or hemorrhagic stroke confirmed by CT or MRI. Transient ischemic attack, subarachnoid hemorrhage, or cerebral venous thrombosis patients were excluded due to their unique pathophysiology, prognosis, and management compared with arterial stroke. The study also excluded individuals already hospitalized at the time of their stroke, those admitted more than 48 hours after their stroke, and those who died during the acute hospitalization period.

Data Collection and Variables

The study's data collection involved extracting demographic information, stroke characteristics, and functional characteristics from medical records.

• Primary Objective: Lower Extremity Motor Impairment and Walking Limitation After Stroke

Lower extremity motor impairment was assessed using the National Institutes of Health Stroke Scale (NIHSS), which measures stroke severity across various domains, including motor function. The NIHSS measures stroke severity across 15 domains with higher scores indicating greater severity of stroke. For this study, the 5-point motor score of the paretic lower extremity with 0 indicating no weakness and 4 indicating no movement of the limb was added to the total score of NIHSS.

Early walking ability was assessed using the AlphaFIM outcome, a reliable measure in the stroke population. Contrary to the Functional Independence Measure (FIM), score is only given on the AlphaFIM if a patient ambulate over 150 feet with or without assistance. For the primary objective, AlphaFIM provides 2 variables relating to walking ability: a binary variable indicating whether a patient could walk in any capacity and an ordinal variable indicating the level of walking ability. The researchers made revisions to the AlphaFIM, changing it from a 7-point scale to a 6-point scale in order to combine patients who require total dependence and those who require maximal assistance into a single value. The study included patients who could immediately walk after a stroke and those who could not, with early walking ability being determined within three days of an ischemic stroke or five days of a hemorrhagic stroke.

• Secondary Objective: Predicting Home Discharge

The secondary objective of the study aimed to predict the likelihood of being discharged home versus elsewhere after the acute hospitalization period following a first-ever stroke. Home discharge without the need for further institutionalization is considered the optimal outcome after a stroke. Therefore, for this analysis, discharge to another hospital, inpatient rehabilitation, or long-term care were grouped together as non-home discharges. The study considered the potential association of age, sex, and various stroke characteristics with home discharge after acute hospitalization, based on previous research. The independent variables for this analysis included demographic information such as age and sex, as well as stroke characteristics, lower extremity motor impairment, and walking ability. The study aimed to explore the predictive nature of these variables in determining the likelihood of being discharged home after acute hospitalization.

Statistical Analysis

The study conducted a comprehensive statistical analysis to investigate the prevalence of lower extremity motor impairment and walking limitations after first-ever stroke and their impact on discharge outcomes. Descriptive statistics were used to summarize the sample, including mean and standard deviation for continuous data, and median and interquartile range for non-normally distributed ordinal and continuous data. The prevalence of lower extremity motor impairment and walking limitation was reported using counts and percentages. Additionally, comparisons between ambulatory and non-ambulatory participants were made using independent t-tests, Mann-Whitney U tests, and χ^2 analyses, and a complete case analysis was performed.

For the secondary objective of predicting discharge home, logistic regression was employed. Univariable logistic regression was initially conducted for each independent variable, followed by multivariable logistic regression using purposeful selection. Two parallel multivariable models were built to avoid collinearity and overlap, assessing variable contributions iteratively until significant variables were identified. Logistic regression assumptions and interactions between significant independent variables were assessed. Model fit and predictive capacity were evaluated using the Hosmer-Lemeshow test, Nagelkerke R^2, and receiver operating characteristic curve analyses, with an emphasis on achieving high area under the curve (AUC) values. Furthermore, an optimal cutoff score for the 6-point walking score was explored, and validity indexes, including sensitivity and specificity, were assessed. The statistical analyses were conducted using RStudio and R version 4.0.1, with a significance level set at P < .05.

Results

In a study of 819 stroke unit admissions, 669 patients were admitted within 48 hours of onset, with 42 (6.3%) dying during acute hospitalization. Of the survivors, 487 had a complete initial NIHSS score and were assessed for early walking ability, comprising the primary population. 140 patients were excluded due to missing initial NIHSS score or early walking ability (22.3%), but they did not differ from the primary population in terms of age, sex, stroke characteristics (side, type, location), or discharge disposition.

This indicates a high level of completeness and generalizability in the primary population. These findings suggest that missing initial NIHSS score or early walking ability did not significantly impact the characteristics of the excluded patients compared to the primary population, supporting the representativeness of the primary population. It is important to note that the excluded patients did not differ in characteristics such as age, sex, stroke characteristics, or discharge disposition, indicating that the primary population may be a reliable sample for the study. This suggests that the results and conclusions drawn from the primary population may be applicable to a wider stroke patient population.

Lower Extremity Motor Impairment and Walking Limitation After Stroke

The study examined the prevalence of lower extremity motor impairment and limitations in walking ability after first-ever stroke, focusing on the differences between patients who could walk immediately after the stroke and those who could not. The data revealed that less than half (44.1%) of the patients presented with lower extremity weakness upon admission for stroke. The distribution of walking scores showed that a significant percentage of patients (57.9%) were unable to walk without assistance within the first 3 to 5 days of stroke. Non-ambulatory patients, including those with total or maximal dependence, had a higher prevalence of hemorrhagic stroke, greater stroke severity, and lower extremity motor impairment compared to ambulatory participants.

The study found that patients who retained or regained some walking function in the early days after stroke had a shorter length of stay and a greater likelihood of returning home after acute hospitalization, highlighting the predictive nature of early walking ability for discharge outcomes. Interestingly, early medical intervention for ischemic stroke, such as thrombolysis or thrombectomy, was not significantly associated with early walking ability.

In conclusion, the study provides contemporary estimates of the prevalence of lower extremity motor impairment and walking limitations after first-ever stroke. It demonstrates the impact of early walking ability on discharge outcomes and highlights the differences between patients who can walk immediately after stroke and those who cannot, shedding light on the significance of early ambulatory capacity in stroke recovery.

Predicting Home Discharge

The research study aimed to estimate the prevalence of lower extremity motor impairment and limitations in walking ability after first-ever stroke and the predictive nature of early walking ability for being discharged home after acute hospitalization. The study found that 50.9% of patients admitted for acute first-ever stroke were discharged home, with a significantly lower rate for non-ambulators compared to those with some ambulatory function. The patients who were discharged home had a mean length of stay of 5.5 days, while those who were discharged to another facility had a mean length of stay of 14 days. Various factors including age, stroke type, severity, location, lower extremity motor impairment, and walking ability were identified as predictors of being discharged home. The patients who had some walking ability were 9.48 times more likely to be discharged home compared to the patients who were non-ambulatory. Using the 6-point AlphaFIM score, the odds of returning home decreased by a factor of 21% for each increment. In addition, a stroke affecting subcortical structures of the brain were less likely to return home.

The study further explored the predictive utility of the ordinal walking scale and identified an optimal cut-off walking score of 3 for predicting home discharge after acute hospitalization, with good sensitivity and specificity. Both models assessing walking ability and stroke severity were considered to have excellent discriminative ability in predicting home discharge.

Overall, the research demonstrated the significant predictive value of early walking ability for home discharge after acute hospitalization following first-ever stroke, emphasizing the importance of assessing lower extremity motor impairment and walking ability in determining discharge outcomes.

Discussion

The study sought to determine the prevalence of lower extremity motor impairment and walking limitations in patients hospitalized with a first-ever stroke and to investigate the predictive value of early walking ability for being discharged home. Results showed that 44.1% of patients had lower extremity motor impairment, and 46.0% to 57.9% were unable to walk without assistance. Of those discharged home, 81.1% had early walking ability, and walking ability was a significant predictor of home discharge.

Prevalence findings were slightly lower than the Copenhagen Stroke Study, possibly due to differences in participant inclusivity. Nevertheless, the rates aligned with recent large-scale acute intervention studies. The study highlighted the predictive nature of lower extremity motor impairment, early walking ability, and initial stroke severity for home discharge. It suggested that a walking assessment after stroke could aid in discharge planning, although causality should not be inferred. Accurate predictions of discharge home post-stroke are crucial and could optimize resource utilization and support social distancing initiatives.

The study's strength lay in its predictive model centered on early lower extremity motor impairment and walking limitation, despite not considering other determinants of discharge disposition. Future research might focus on those with severe walking deficits after stroke, as they may need the most support at home or in another institution.

Limitations

The study has certain limitations that should be considered. The exclusion of patients who died from stroke, had recurrent stroke, were already in the hospital for other medical reasons, or were admitted more than 48 hours after their stroke reduces the generalizability of the findings to a more diverse stroke population. Additionally, a moderate proportion of admissions had missing data and were excluded, which could have potentially resulted in different findings if the dataset was complete. It is also noted that the data were collected from a large hospital with a specialized stroke unit, which may not be fully representative of typical stroke admissions to a local acute care hospital.

In conclusion, the study found that approximately half of patients experiencing a first-ever stroke will have lower extremity weakness and encounter walking limitations. Furthermore, early walking ability was identified as a significant predictor of returning home after acute hospitalization, regardless of stroke severity. This suggests that knowledge of a patient's early walking ability could enable physical therapists to initiate discharge planning early after a stroke using a simple assessment of walking function.

Opportunities for Future Research

1. Investigate the long-term impact of lower extremity motor impairment and walking limitation post-stroke on functional independence, community mobility, and quality of life in the chronic stage of stroke recovery.

2. Examine the changing trends in the prevalence of lower extremity motor impairment and walking limitation post-stroke, considering factors such as earlier detection, improved medical care, and increasing incidence in younger adults, and how these trends affect rehabilitation and resource planning.

3. Explore the association of early walking ability with other important outcomes such as stroke severity, community reintegration, and health care utilization to better understand the comprehensive impact of walking ability on stroke recovery and post-acute care.

4. Investigate the predictive ability of different functional measures, including walking ability, in determining discharge disposition after acute hospitalization, and compare the predictive ability of walking ability with traditional measures of stroke severity.

5. Examine the potential causal relationship between early therapy aimed at improving walking ability and discharge outcomes, to assess whether interventions targeting walking ability can lead to better discharge outcomes.

6. Conduct a multi-site study to further validate the role of early walking assessments in predicting discharge disposition after acute hospitalization, considering diverse stroke populations and healthcare settings.