Objective We investigated the prevalence of restless legs syndrome (RLS) in Japanese patients with type 2 diabetes and assessed the efficacy of pramipexole therapy.

Design One hundred patients with type 2 diabetes without secondary causes of RLS were sequentially screened for the 12-week, prospective, single arm study. RLS was screened by essential diagnostic criteria developed by the International Restless Legs Study Group. Diabetic neuropathy was diagnosed by nerve conductance study. Severity of RLS and sleep quality were assessed by the International Restless Legs Rating Scale (IRLS) and the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J), respectively. Pramipexole was administered for 12 weeks. The primary end point was change in the IRLS score in 12 weeks and secondary end points were change in PSQI-J and glycated haemoglobin (HbA1c) in 12 weeks.

Results RLS was diagnosed in 8 of 100 participants (8%). Diabetic neuropathy was most likely associated with RLS (OR 3.81, 95% CI 0.85 to 17.05, p=0.111). The IRLS score was improved from 19.0±5.6 to 5.4±4.8 by pramipexole in 12 weeks (p<0.001). The change in the score was −13.6 (95% CI −15.5 to −11.7; p<0.05). PSQI-J was improved from 6.0±4.4 to 1.5±1.3 in 12 weeks (p<0.05). Change in PSQI-J was −4.5 (95% CI −6.8 to −2.1; p<0.05). HbA1c was slightly decreased from 7.19±0.56% (55±6 mmol/mol) to 6.90±0.48% (52±5 mmol/mol) in 12 weeks (p<0.05). Change in HbA1c was −0.29% (−3 mmol/mol) (95% CI −0.37% to −0.20% (−4 to −2 mmol/mol;) p<0.05).

Conclusions We find that type 2 diabetes is a possible risk factor for RLS in the Japanese population, and that pramipexole treatment can improve the symptoms of RLS as well as the quality of sleep and glycaemic control in these patients.

Trial registration number University hospital Medical Information Network in Japan (UMIN000008347).