Restless leg syndrome is common in patients with obstructive sleep apnoea

Background Obstructive sleep apnea (OSA) is one of the diseases related to restless leg syndrome (RLS). RLS often persists after positive airway pressure therapy (PAP) for OSA has been prescribed and can be the reason for lower adherence. The aim of this study was to evaluate residual RLS in patients on PAP therapy.

Methods We prospectively recruited patients on PAP therapy. They filled the Restless Leg Syndrome Rating Scale. Adherence to PAP therapy was obtained from machines software and medical records were analyzed.

Results 71 patients (21% women, age 56.6 ± 10.7 years, BMI 36.0 ± 9.1, ESS 11.4 ± 5.7) were recruited. Initial apnea hypopnea index (AHI) was 48.4 ± 22.3, mean AHI on PAP therapy was 5.1 ± 5.4, average usage was 5.2h ± 2.3h. 63% of patients were adherent to PAP therapy.65% patients had arterial hypertension (AH), 11% ischemic heart disease,27% diabetes mellitus (DM), 16%chronic heart failure, 6% atrial fibrilation, 17% had either asthma or COPD. Only 23 (33%) patients reported no symptoms of RLS, 20 (29%) complained of mild RLS, 16 (23%) of moderate, and 11 (15%) of severe RLS. Those with severe RLS had higher initial ESS (15.0 ± 2.4 vs. 10.8 ± 5.9, p=0.004), had more often DM (32% vs 10%, p=0.025), asthma (50% vs. 11%, p=0.004), and clinically significant insomnia (67% vs. 8%, p<0.001). There was a trend of higher prevalence of AH across RLS severity (35% - no RLS, 80% mild RLS, 75% moderate RLS, and severe RLS 82%, p=0.008)

Conclusions RLS is common in patients with OSA on PAP therapy. Those with severe RLS have higher ESS when diagnosed with OSA, more often have diabetes mellitus, asthma, and clinically significant insomnia. AH is more common in patients with comorbid RLS.