Subashan Perera

Gait Speed and Survival in Older Adults

CONTEXT Survival estimates help individualize goals of care for geriatric patients, but life tables fail to account for the great variability in survival. Physical performance measures, such as gait speed, might help account for variability, allowing clinicians to make more individualized estimates. OBJECTIVE To evaluate the relationship between gait speed and survival. DESIGN, SETTING, AND PARTICIPANTS Pooled analysis of 9 cohort studies (collected between 1986 and 2000), using individual data from 34,485 community-dwelling older adults aged 65 years or older with baseline gait speed data, followed up for 6 to 21 years. Participants were a mean (SD) age of 73.5 (5.9) years; 59.6%, women; and 79.8%, white; and had a mean (SD) gait speed of 0.92 (0.27) m/s. MAIN OUTCOME MEASURES Survival rates and life expectancy. RESULTS There were 17,528 deaths; the overall 5-year survival rate was 84.8% (confidence interval [CI], 79.6%-88.8%) and 10-year survival rate was 59.7% (95% CI, 46.5%-70.6%). Gait speed was associated with survival in all studies (pooled hazard ratio per 0.1 m/s, 0.88; 95% CI, 0.87-0.90; P < .001). Survival increased across the full range of gait speeds, with significant increments per 0.1 m/s. At age 75, predicted 10-year survival across the range of gait speeds ranged from 19% to 87% in men and from 35% to 91% in women. Predicted survival based on age, sex, and gait speed was as accurate as predicted based on age, sex, use of mobility aids, and self-reported function or as age, sex, chronic conditions, smoking history, blood pressure, body mass index, and hospitalization. CONCLUSION In this pooled analysis of individual data from 9 selected cohorts, gait speed was associated with survival in older adults.

Meaningful Change and Responsiveness in Common Physical Performance Measures in Older Adults

OBJECTIVES: To estimate the magnitude of small meaningful and substantial individual change in physical performance measures and evaluate their responsiveness.

Physical Performance Measures in the Clinical Setting

OBJECTIVES:  To assess the ability of gait speed alone and a three‐item lower extremity performance battery to predict 12‐month rates of hospitalization, decline in health, and decline in function in primary care settings serving older adults.

Randomized Clinical Trial of Therapeutic Exercise in Subacute Stroke

BACKGROUND AND PURPOSE Rehabilitation care after stroke is highly variable and increasingly shorter in duration. The effect of therapeutic exercise on impairments and functional limitations after stroke is not clear. The objective of this study was to determine whether a structured, progressive, physiologically based exercise program for subacute stroke produces gains greater than those attributable to spontaneous recovery and usual care. METHODS This randomized, controlled, single-blind clinical trial was conducted in a metropolitan area and 17 participating healthcare institutions. We included persons with stroke who were living in the community. One hundred patients (mean age, 70 years; mean Orpington score, 3.4) consented and were randomized from a screened sample of 582. Ninety-two subjects completed the trial. Intervention was a structured, progressive, physiologically based, therapist-supervised, in-home program of thirty-six 90-minute sessions over 12 weeks targeting flexibility, strength, balance, endurance, and upper-extremity function. Main outcome measures were postintervention strength (ankle and knee isometric peak torque, grip strength), upper- and lower-extremity motor control (Fugl Meyer), balance (Berg and functional reach), endurance (peak aerobic capacity and exercise duration), upper-extremity function (Wolf Motor Function Test), and mobility (timed 10-m walk and 6-minute walk distance). RESULTS In the intention-to-treat multivariate analysis of variance testing the overall effect, the intervention produced greater gains than usual care (Wilks lambda=0.64, P=0.0056). Both intervention and usual care groups improved in strength, balance, upper- and lower-extremity motor control, upper-extremity function, and gait velocity. Gains for the intervention group exceeded those in the usual care group in balance, endurance, peak aerobic capacity, and mobility. Upper-extremity gains exceeded those in the usual care group only in patients with higher baseline function. CONCLUSIONS This structured, progressive program of therapeutic exercise in persons who had completed acute rehabilitation services produced gains in endurance, balance, and mobility beyond those attributable to spontaneous recovery and usual care.

Persisting Consequences of Stroke Measured by the Stroke Impact Scale

Background and Purpose— The purpose of this study was to compare disability and quality of life as measured by the Stroke Impact Scale (SIS) of stroke patients deemed recovered (Barthel Index ≥95) with 2 stroke-free populations of community-dwelling elderly. Methods— Eighty-one stroke patients who participated in the Kansas City Stroke Registry and achieved a Barthel Index of ≥95 at 3 months after stroke and 246 stroke-free subjects enrolled in the Community Elders Study were enrolled in this study. The Community Elders Study group was further divided into 2 groups, those recruited from the Department of Veterans Affairs Health System (VA) and a those from a local health maintenance organization (HMO). Stroke patients were administered the SIS ≈90 days after stroke, and the stroke-free community dwellers were administered a version of the SIS adapted for nonstroke subjects, the Health Impact Scale (HIS). A general linear model was used to examine differences in health outcomes measured by the SIS or HIS between the KCSR stroke patients and VA and HMO community-dwelling elders after controlling for medical comorbidities and demographics. Results— Kansas City Stroke Registry participants were significantly older than the community study groups (P =0.0052). Selected medical conditions were similar among the 3 study groups. Old age and a history of diabetes mellitus were more likely to be associated with more deficits and poor quality of life. In stroke patients deemed recovered, stroke still affected hand function, activities and independent activities of daily living, participation, and overall physical function compared with the stroke-free community dwellers in the HMO health system even after adjustment for age and diabetes status. Stroke-free community dwellers in the VA health system also had worse social participation than the stroke-free community dwellers in the HMO health system. Conclusions— Research and clinicians have consistently underestimated the impact of stroke with the Barthel Index. This has major implications for the design of therapeutic trial designs and adequate assessments of social and economic sequelae of stroke.

Improvements in Speed-Based Gait Classifications Are Meaningful

Background and Purpose— Gait velocity is a powerful indicator of function and prognosis after stroke. Gait velocity can be stratified into clinically meaningful functional ambulation classes, such as household ambulation (<0.4 m/s), limited community ambulation (0.4 to 0.8 m/s), and full community ambulation (>0.8 m/s). The purpose of the current study was to determine whether changes in velocity-based community ambulation classification were related to clinically meaningful changes in stroke-related function and quality of life. Methods— In subacute stroke survivors with mild to moderate deficits who participated in a randomized clinical trial of stroke rehabilitation and had a baseline gait velocity of 0.8 m/s or less, we assessed the effect of success versus failure to achieve a transition to the next class on function and quality of life according to domains of the Stroke Impact Scale (SIS). Results— Of 64 eligible participants, 19 were initially household ambulators, and 12 of them (68%) transitioned to limited community ambulation, whereas of 45 initially limited community ambulators, 17 (38%) became full community ambulators. Function and quality-of-life SIS scores after treatment were significantly higher among survivors who achieved a favorable transition compared with those who did not. Among household ambulators, those who transitioned to limited or full community ambulation had significantly better SIS scores in mobility (P=0.0299) and participation (P=0.0277). Among limited community ambulators, those who achieved the transition to full community ambulatory status had significantly better scores in SIS participation (P=0.0085). Conclusions— A gait velocity gain that results in a transition to a higher class of ambulation results in better function and quality of life, especially for household ambulators. Household ambulators possibly had more severe stroke deficits, reducing the risk of “ceiling” effects in SIS-measured activities of daily living and instrumental activities of daily living. Outcome assessment based on transitions within a mobility classification scheme that is rooted in gait velocity yields potentially meaningful indicators of clinical benefit. Outcomes should be selected that are clinically meaningful for all levels of severity.

Improvement in Usual Gait Speed Predicts Better Survival in Older Adults

OBJECTIVES: To estimate the relationship between 1‐year improvement in measures of health and physical function and 8‐year survival.

Is Timed Up and Go Better Than Gait Speed in Predicting Health, Function, and Falls in Older Adults?

OBJECTIVES: To assess whether the Timed Up and Go (TUG) is superior to gait speed in predicting multiple geriatric outcomes.

Stroke Impact Scale-16: A brief assessment of physical function

Objectives: To 1) develop a short instrument (Stroke Impact Scale–16 [SIS-16]) to assess physical function in patients with stroke at approximately 1 to 3 months poststroke using items from the composite physical domain of the Stroke Impact Scale (SIS) version 3.0, and 2) compare the SIS-16 and a commonly used disability measure, the Barthel Index (BI), in terms of their ability to discriminate disability. Methods: A total of 621 subjects enrolled in the GAIN Americas randomized stroke trial were included in this study. Rasch analysis, which models the probability of a subject’s response to an item using both subject ability and item difficulty, was used to construct the SIS-16, describe its properties, and compare its ordering and range of item difficulties to those of the BI. Box plots and analysis of variance were used to examine differences in BI and SIS-16 scores across modified Rankin categories. Results: The study sample had an average age of 68 ± 12.4 years and 56% were men. Stroke diagnoses were classified as minor in 91 patients (NIH Stroke Scale score [NIHSS] 0 to 5), moderate in 304 (NIHSS 6 to 13), and major in 226 (NIHSS ≥ 14). Twelve of the original 28 items in the SIS version 3.0 composite physical domain were eliminated to produce the SIS-16, with a minimal loss of reliability. As compared to the BI, the SIS-16 contains more difficult items that can differentiate patients with less severe limitations, and therefore has less pronounced ceiling effects. SIS-16 scores were significantly different across Rankin levels 0 to 1, 2, 3, 4, and 5, whereas BI was significantly different only across Rankin levels 0 to 2, 3, 4, and 5. Conclusion: Compared to the BI, the SIS-16 is an excellent collection of items suitable for assessing a wide range of physical function limitations of patients with stroke at 1 to 3 months poststroke. Because of a less pronounced ceiling effect, the SIS-16 can differentiate lower levels of disability as compared to the BI.

Evaluation of Proxy Responses to the Stroke Impact Scale

Background and Purpose— The purposes of this study were to compare proxy-patient responses on each domain of the Stroke Impact Scale (SIS) and the SIS-16, estimate the bias, and evaluate the validity of proxy scores. Methods— Two hundred eighty-seven patient and proxy pairs from the Kansas City Stroke Registry participated in the study. All patients were assessed in their home or nursing facility between 90 and 120 days after stroke with the use of the modified Rankin Scale Motricity Index (strength), Barthel Index (activities of daily living), Lawton assessment (instrumental activities of daily living), Folstein Mini-Mental State Examination (cognition), and the SIS. Eligible proxies were individuals who were aged ≥18 years, had known the patient for at least 1 year, and saw the patient at least once each week. All proxy interviews were conducted within 7 days of (before or after) the patient’s interview. Results— Three hundred seventy-seven patients from the Kansas City Stroke Registry were eligible for the study. Seventy-seven patients or proxies refused participation. Thirteen patients of the consenting patient-proxy pairs were too aphasic or cognitively impaired to complete the interviews and were dropped from the study. Proxies scored patients as more severely affected than patients scored themselves on the SIS-16 and in 7 of 8 domains of the full SIS (5 were statistically significant at &agr;=0.05). The proxy bias toward overrating the severity of the patient’s condition tended to increase as the severity of the stroke increased. However, the magnitude of the biases between patient and proxy means, as measured by effect size, was small (range, −0.1 to 0.4). The strength of the agreement, as measured by intraclass correlation coefficients, between proxy and patient ranged from 0.50 to 0.83. Agreement was best for the observable physical domains. Both patient and proxy scores in all domains were significantly different across Rankin categories. Concurrent validity for both patient and proxy correlations with the Folstein Mini-Mental State Examination, Barthel Index, Lawton instrumental activities of daily living, and Motricity Index was good to excellent (range, 0.37 to 0.78). Conclusions— Proxies provide valid information for assessment of stroke outcomes. There are significant differences between patient and proxy reporting on SIS domains and the SIS-16. However, the observed biases are small and not clinically meaningful.