Dear Editor,
We thank the authors for their insightful comments on our article titled “Efficacy and Safety of Pregabalin for Restless Legs Syndrome in Korean Adults: A Randomized, Double-Blind, Placebo-Controlled Trial”.1 Their observations allow us to further clarify the design and intended scope of our study.
Regarding the use of polysomnography (PSG), we agree that making objective measurements can improve the understanding of sleep disturbance in restless legs syndrome (RLS). Previous PSG studies have demonstrated that pregabalin not only reduces periodic limb movements in sleep (PLMS) but also improves the sleep architecture by reducing wakefulness after sleep onset and the N1 percentage while increasing the sleep efficiency and amount of slow-wave sleep in patients with RLS.2,3 Recent recommendations further suggest that PLMS can serve not only as a surrogate marker of cardiovascular risk but also as a valuable endpoint in clinical trials, given the relatively low placebo response rate,4 thereby reinforcing the potential utility of PSG in RLS trials. However, the utility of PSG in all patients is constrained by several factors. PSG typically involves obtaining data only during a single night and so may not account for the well-recognized night-to-night variability of RLS symptoms.5 In addition, PLMS are absent in up to 40% of Asian patients with RLS,6,7,8 which reduces their diagnostic sensitivity. Considering the high cost and logistical challenges of PSG, we opted to employ validated clinical instruments, which currently are the most-common method used in trials on diagnosing and treating RLS.
Regarding the 12-week study duration, we fully acknowledge that long-term studies are essential to evaluate augmentation and sustained efficacy. Indeed, Garcia-Borreguero et al.4 emphasized the importance of longer-term, withdrawal-design trials for chronic conditions such as RLS. However, our trial was designed to investigate the short-term efficacy and safety of pregabalin in Korean adults—a population in which no previous prospective pregabalin trial had been conducted. Our findings should therefore be interpreted within this context, while reinforcing the need for future long-term studies to address augmentation and other delayed outcomes.
In conclusion, while PSG and PLMS-based endpoints represent promising directions for future research, our pragmatic design was intended to provide an initial step toward understanding the utility of pregabalin therapy in Korean patients with RLS. We hope that our study helps lay the foundation for larger and longer-term investigations.
Footnotes
Ethics Statement: Not applicable
- Writing—original draft: Ki-Young Jung.
- Writing—review & editing: Ki-Young Jung, Jun-Sang Sunwoo.
Conflicts of Interest: The authors have no potential conflicts of interest to disclose.
Funding Statement: None
Availability of Data and Material
Data sharing not applicable to this article as no datasets were generated or analyzed during the study.
References
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Data Availability Statement
Data sharing not applicable to this article as no datasets were generated or analyzed during the study.