Feasibility and Inter-Rater Reliability of Physical Performance Measures in Acutely Admitted Older Medical Patients

Objective Physical performance measures can be used to predict functional decline and increased dependency in older persons. However, few studies have assessed the feasibility or reliability of such measures in hospitalized older patients. Here we assessed the feasibility and inter-rater reliability of four simple measures of physical performance in acutely admitted older medical patients. Design During the first 24 hours of hospitalization, the following were assessed twice by different raters in 52 (>= 65 years) patients admitted for acute medical illness: isometric hand grip strength, 4-meter gait speed, 30-s chair stand and Cumulated Ambulation Score. Relative reliability was expressed as weighted kappa for the Cumulated Ambulation Score or as intra-class correlation coefficient (ICC1,1) and lower limit of the 95%-confidence interval (LL95%) for grip strength, gait speed, and 30-s chair stand. Absolute reliability was expressed as the standard error of measurement and the smallest real difference as a percentage of their respective means (SEM% and SRD%). Results The primary reasons for admission of the 52 included patients were infectious disease and cardiovascular illness. The mean +/- SD age was 78 +/- 8.3 years, and 73.1% were women. All patients performed grip strength and Cumulated Ambulation Score testing, 81% performed the gait speed test, and 54% completed the 30-s chair stand test (46% were unable to rise without using the armrests). No systematic bias was found between first and second tests or between raters. The weighted kappa for the Cumulated Ambulation Score was 0.76 (0.60-0.92). The ICC1,1 values were as follows: grip strength, 0.95 (LL95% 0.92); gait speed, 0.92 (LL95% 0.73), and 30-s chair stand, 0.82 (LL95% 0.67). The SEM% values for grip strength, gait speed, and 30-s chair stand were 8%, 7%, and 18%, and the SRD95% values were 22%, 17%, and 49%. Conclusion In acutely admitted older medical patients, grip strength, gait speed, and the Cumulated Ambulation Score measurements were feasible and showed high inter-rater reliability when administered by different raters. The feasibility and inter-rater reliability of the 30-s chair stand were moderate, complicating the use of the 30-s chair stand in acutely admitted older medical patients. However, the predefined modified version of the chair stand test was both feasible and with high inter-rater reliability in this population.