To systematically evaluate the prevalence, clinical profiles, and treatment outcomes in patients with comorbid RLS and OSA and to assess the impact of OSA therapy on RLS symptoms.

We conducted a systematic review of observational studies indexed in MedLine, PubMed, and EMBASE through August 2025. The review followed PRISMA guidelines and was registered in PROSPERO. The Inclusion criteria were studies reporting original data on adult patients with comorbid RLS and OSA, including clinical features and treatment outcomes. Study quality was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Ten studies were included, comprising over 3000 participants. The prevalence of RLS among patients with OSA ranged from 10 % to 30 %. Comorbidity was associated with increased rates of insomnia, fatigue, depression, and reduced response to OSA therapy. In multiple studies, CPAP treatment led to improvement in RLS symptoms, including reduced medication use in over 70 % of patients in some cohorts. However, therapeutic response was variable, with some patients exhibiting persistent or CPAP-emergent periodic limb movements. The quality of the studies included was mainly fair, with two rated as good.

Comorbid RLS and OSA represent a clinically distinct phenotype characterized by a greater symptom burden and more complex treatment trajectories. CPAP may offer therapeutic benefit for RLS in many patients.