03343nas a2200457 4500008004100000022001400041245012900055210006900184260001300253300001200266490000700278520198400285653003102269653000902300653002802309653001902337653001602356653002602372653001102398653000902409653002502418653001102443653002002454653000902474653002402483653003302507653003202540653002002572653001702592653001802609100002302627700001702650700002402667700002402691700002102715700002502736700002102761700002002782710004702802856003602849 2008 eng d a1532-541500aIncident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease.0 aIncident physical disability in people with lower extremity peri c2008 Jun a1037-440 v563 a

OBJECTIVES: To evaluate the risk of incident physical disability and the decline in gait speed over a 6-year follow-up associated with a low ankle-arm index (AAI) in older adults.

DESIGN: Observational cohort study.

SETTING: Forsyth County, North Carolina; Sacramento County, California; Washington County, Maryland; and Allegheny County, Pennsylvania.

PARTICIPANTS: Four thousand seven hundred five older adults, 58% women and 17.6% black, participating in the Cardiovascular Health Study.

MEASUREMENTS: AAI was measured in 1992/93 (baseline). Self-reported mobility, activity of daily living (ADL), and instrumental activity of daily living (IADL) disability and gait speed were recorded at baseline and at 1-year intervals over 6 years of follow-up. Mobility disability was defined as any difficulty walking half a mile and ADL and IADL disability was defined as any difficulty with 11 specific ADL and IADL tasks. Individuals with mobility, ADL, or IADL disability at baseline were excluded from the respective incident disability analyses.

RESULTS: Lower baseline AAI values were associated with increased risk of mobility disability and ADL/IADL disability. Clinical cardiovascular disease (CVD), diabetes mellitus, and interim CVD events partially explained these associations for mobility disability and clinical CVD and diabetes mellitus partially explained these associations for ADL and IADL disability. Individuals with an AAI less than 0.9 had on average a mean decrease in gait speed of 0.02 m/s per year, or a decline of 0.12 m/s over the 6-year follow-up. Prevalent CVD partly explained this decrease but interim CVD events did not further attenuate it.

CONCLUSION: Low AAI serves as marker of future disability risk. Reduction of disability risk in patients with a low AAI should consider cardiovascular comorbidity and the prevention of additional disabling CVD events.

10aActivities of Daily Living10aAged10aCardiovascular Diseases10aCohort Studies10aComorbidity10aDisability Evaluation10aFemale10aGait10aGeriatric Assessment10aHumans10aLower Extremity10aMale10aMobility Limitation10aPeripheral Vascular Diseases10aProportional Hazards Models10aRisk Assessment10aRisk Factors10aUnited States1 aBrach, Jennifer, S1 aSolomon, Cam1 aNaydeck, Barbara, L1 aSutton-Tyrrell, Kim1 aEnright, Paul, L1 aJenny, Nancy, Swords1 aChaves, Paulo, M1 aNewman, Anne, B1 aCardiovascular Health Study Research Group uhttps://chs-nhlbi.org/node/102402434nas a2200337 4500008004100000022001400041245010100055210006900156260001300225300001100238490000700249520148300256653003101739653000901770653002801779653002601807653001301833653001101846653000901857653001801866653001101884653000901895653001701904653001901921653003101940100002301971700002101994700002502015700002002040856003602060 2008 eng d a1532-821X00aThe reliability and validity of measures of gait variability in community-dwelling older adults.0 areliability and validity of measures of gait variability in comm c2008 Dec a2293-60 v893 a

OBJECTIVE: To examine the test-retest reliability and concurrent validity of variability of gait characteristics.

DESIGN: Cross-sectional study.

SETTING: Research laboratory.

PARTICIPANTS: Older adults (N=558) from the Cardiovascular Health Study.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances.

RESULTS: Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22-.48 and ICC=.40-.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P<.05).

CONCLUSIONS: Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved.

10aActivities of Daily Living10aAged10aCross-Sectional Studies10aDisability Evaluation10aExercise10aFemale10aGait10aHealth Status10aHumans10aMale10aPennsylvania10aRehabilitation10aReproducibility of Results1 aBrach, Jennifer, S1 aPerera, Subashan1 aStudenski, Stephanie1 aNewman, Anne, B uhttps://chs-nhlbi.org/node/106503468nas a2200361 4500008004100000022001400041245012800055210006900183260001700252300001000269490000700279520239100286653000902677653002202686653002602708653001102734653000902745653002502754653001102779653002302790653000902813653002402822653003202846653002102878653002402899653003102923100002302954700001602977700002902993700002003022700002803042856003603070 2012 eng d a2152-089500aUse of stance time variability for predicting mobility disability in community-dwelling older persons: a prospective study.0 aUse of stance time variability for predicting mobility disabilit c2012 Jul-Sep a112-70 v353 a

BACKGROUND AND PURPOSE: Mobility disability is a serious and frequent adverse health outcome associated with aging. Early identification of individuals at risk for mobility disability is important if interventions to prevent disability are to be instituted. The objectives of this prospective study were to (1) determine the magnitude of stance time variability (STV) that discriminates individuals who currently have mobility disability (prevalent mobility disability) and (2) determine the magnitude of STV that predicts a new onset of mobility disability at 1 year (incident mobility disability).

METHODS: A total of 552 community-dwelling older adults were evaluated as part of the Cardiovascular Health Study, a longitudinal cohort study. Stance time, in milliseconds, was determined from 2 passes on a 4-m computerized walkway at self-selected walking speed, and STV was defined as the standard deviation from approximately 12 individual steps. Mobility disability was defined as self-reported difficulty walking a one-half mile. Receiver operating characteristic (ROC) curves were plotted to determine an optimal cutoff value for STV for prevalent and incident mobility disability, and the area under the receiver operating characteristic curve (AUC) was computed.

RESULTS: The optimal cutoff score for STV (maximizing sensitivity and specificity) for prevalent mobility disability was 0.037 seconds (sensitivity = 65%, specificity = 65%, AUC = 0.70) and for incident 1-year mobility disability was 0.034 seconds (sensitivity = 61%, specificity = 60%, AUC = 0.65). The use of likelihood ratios demonstrated a gradient of risk across values of STV, with mobility risk increasing as values of STV increased.

DISCUSSION AND CONCLUSION: Values of STV may be useful in identifying older adults with mobility disability and at risk for future disability. We recommend the more conservative estimate for identifying risk, STV = 0.034 seconds, which maximizes the sensitivity and minimizes false negatives. The relatively modest values on the validity indices could possibly be improved by increasing the reliability of the measurement of STV. Clinicians should interpret the cutoff values liberally and use STV in conjunction with other measures until further work is completed to validate STV as an indicator of mobility disability.

10aAged10aAged, 80 and over10aDisability Evaluation10aFemale10aGait10aGeriatric Assessment10aHumans10aIndependent Living10aMale10aMobility Limitation10aPhysical Therapy Modalities10aPostural Balance10aProspective Studies10aReproducibility of Results1 aBrach, Jennifer, S1 aWert, David1 aVanSwearingen, Jessie, M1 aNewman, Anne, B1 aStudenski, Stephanie, A uhttps://chs-nhlbi.org/node/1363