Ambulatory physical activity, disease severity, and employment status in adult women with osteoarthritis of the hip.

OBJECTIVE: To measure ambulatory physical activity and determine associations between physical inactivity and joint function, gait function, disease severity, and employment status in adult women with hip osteoarthritis (OA) living in the community.
METHODS: Sixty-five adult women with hip OA were recruited from an outpatient clinic. Ambulatory physical activity was measured using an activity monitor based on an accelerometer over 7 days, which estimated step counts, net energy expenditure, and time spent in activity by acceleration intensity. The Harris hip score, walking speed, and radiographic stage were assessed for joint function, gait function, and disease severity, respectively. Employment status was classified into unemployed and employed (sitting occupations and standing/walking occupations).
RESULTS: More than 40% of patients were classified as inactive, with less time spent in moderate-intensity activity (median 5.6 vs 22.9 min/day) compared with their counterparts. Employment status and the presence or absence of stage 4 (endstage) arthritis were independently associated with activity classification, and there was an interaction between these 2 variables; i.e., although stage 4 arthritis was associated with inactivity in patients who were unemployed, it bore no relationship in patients who were employed.
CONCLUSION: A significant proportion of adult women with hip OA were physically inactive, with a lack of moderate-intensity activity. The possible interaction between endstage OA and employment status requires further study to determine whether being at work negates the adverse effects of endstage OA or whether higher functioning due to physical activity enables patients with endstage OA to be employed.