Response to the Letter Regarding "Positional Obstructive Sleep Apnea and Periodic Limb Movements During Sleep: A Large Multicenter Study".

Abstract

We appreciate the thoughtful comments regarding our study on the relationship between positional obstructive sleep apnea (POSA), OSA severity, and periodic limb movements during sleep (PLMS). In our large multicenter analysis, PLMS prevalence decreased with increasing OSA severity and was significantly higher in patients with POSA, particularly those with severe OSA. While our findings align with previous reports, differences among studies-such as that of Budhiraja et al.- may reflect variation in confounder control, including medication use, which was not captured in our retrospective, anonymized dataset. We acknowledge that iron-related laboratory parameters, including serum ferritin, were not available due to the nature of the dataset. Nonetheless, iron deficiency remains an important consideration in PLMS pathophysiology. Future prospective studies should include detailed clinical, pharmacologic, and laboratory data to clarify these associations. We thank the correspondent for the opportunity to address these important points.