Hip pain while using lower extremity joints and sleep disturbances in elderly white women: results from a cross-sectional analysis.

OBJECTIVE: To evaluate sleep quality in women with hip pain due to daily activities involving the lower extremity joints.
METHODS: We evaluated the association of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) hip pain severity score with objective sleep measures obtained by wrist actigraphy in 2,225 white women ≥ 65 years of age enrolled in the Study of Osteoporotic Fractures.
RESULTS: Women had an increased odds of spending ≥ 90 minutes awake after sleep onset (odds ratio [OR] 1.28, 95% confidence interval [95% CI] 1.11-1.50) for every 5-point increase in hip pain score after adjustment for all covariates. Hip pain when sitting or lying was the strongest predictor of sleep fragmentation (OR 2.0, 95% CI 1.47-2.73); however, standing pain was associated with a higher number of awake minutes in bed scored from sleep onset to the end of the last sleep episode, independent of pain while in bed (OR 1.41, 95% CI 1.07-2.01). Sleep disturbances increased significantly after the first 2 hours of sleep in women with severe hip pain compared to those without hip pain (mean ± SD 1.4 ± 0.47 minutes per hour of sleep; P < 0.003). Similar associations were observed for long wake episodes >5 minutes. There were no associations between daytime napping, sleep latency, sleep efficiency, and total sleep minutes and WOMAC hip pain.
CONCLUSION: Fragmented sleep was greater in women with hip pain compared to those without hip pain; however, fragmented sleep in women with severe hip pain compared to those without hip pain was unchanged until after the first 2 hours of sleep. Further investigations into pain medications wearing off over time or the prolonged periods of inactivity decreasing the pain threshold are warranted.