Increased frequency of restless legs syndrome in chronic obstructive pulmonary disease patients.

BACKGROUND

Despite complaints of poor sleep being very common in people with chronic obstructive pulmonary disease (COPD), restless legs syndrome (RLS) symptoms have not been extensively investigated in these patients.

OBJECTIVE

To assess the prevalence and severity of RLS in patients with COPD and to investigate the factors potentially associated with RLS.

METHODS

A total of 87 patients with COPD and 110 controls, matched for age and sex, were evaluated regarding the presence and severity of RLS symptoms. A diagnosis of RLS was made according to the criteria of the International RLS Study Group (IRSLSSG), and severity was assessed by the IRLSSG severity scale. Excessive daytime somnolence was assessed using the Epworth sleepiness scale (ESS).

RESULTS

RLS was significantly more frequent in COPD patients than in controls (36.8% vs. 11%; p < 0.001). Compared to controls, COPD patients with RLS showed higher disease severity (mean IRLSSG severity scale score: 20.5 +/- 2.8 for COPD, and 18 +/- 3.5 for controls; p = 0.016) and more pronounced daytime somnolence (mean ESS score: 11.8 +/- 1.1 for COPD, and 8.6 +/- 3.6 for controls; p = 0.009). Moreover, compared to those without RLS, COPD patients with RLS showed increased daytime sleepiness (mean ESS score: 11.8 +/- 1.1 for COPD/RLS, and 7.3 +/- 4 for COPD/non-RLS; p < 0.001) and longer disease duration (11.9 +/- 7 years for COPD/RLS, and 8.7 +/- 6.9 years for COPD/non-RLS; p = 0.045). Multivariate analysis showed that ESS score was the only factor significantly associated with RLS in COPD patients.

CONCLUSIONS

RLS is a frequent cause of disabling sleep disturbance in patients with COPD and should be specifically investigated in these patients.