National RLS Opioid Registry: Four-year Dose Stability, Efficacy and Tolerability
April 2024Sleep 47(Supplement_1):A293-A293 John Winkelman
Introduction
Refractory or augmented restless legs syndrome (RLS) is often treated with opioids. Despite their short-term efficacy, concerns about long-term efficacy, dose stability, and tolerability persist. The National RLS Opioid Registry is a longitudinal, observational study tracking the long-term efficacy, dose stability, and tolerability of opioids for RLS.
Methods
Extensive interviews were conducted with a baseline population of 500, from 44 US states and 4 countries. All participants have a history of therapeutic response to dopamine agonists–a majority experienced augmentation–and take prescribed opioids for RLS (median duration at BL=2-years). Biannual self-report questionnaires track opioid dosage, side effects, RLS severity, and other relevant factors. No clinical guidance or intervention is provided.
Results
At 4-years, 423 participants continue opioid treatment and study participation (5.8% lost to follow-up or withdrew, 2.4% died, 6.6% stopped opioids). Methadone and oxycodone are the two most common opioids (taken by 54.7% and 21.9% of 4-year participants, respectively). Mean RLS severity (baseline IRLS=13.0; 4-year IRLS=13.3) and sleep disturbance (baseline ISI=10.5, 4-year ISI=9.9) were stable from baseline to 4-years in the Registry. Median daily opioid dose is also unchanged, at 30 MME (equivalent to methadone 7.5 mg or oxycodone 20 mg). Opioid doses were increased by 49.4% of participants (median increase=11.3 MME) and decreased by 19.2% (median decrease=10.5 MME). Large dose increases (25-50 MME or >50 MME) occurred in 5.0% and 5.4% of participants, respectively. Several factors were associated with larger dose increases, including switching opioid medications (OR=3.61, 95% CI [1.80-7.27]), under one year on opioids at baseline (OR=2.03, 95% CI [1.00-4.09]), significant baseline depression (PHQ-9>4) (OR=2.57 95% CI [1.27-5.51]), use of opioids for comorbid pain conditions (OR=3.18, 95% CI [1.21-7.89]), dopamine agonist addition (OR=3.06, 95% CI [0.92-8.77]) or discontinuation (OR=3.16, 95% CI [1.13-8.26]) since baseline, and painful RLS at baseline (OR=3.85, 95% CI [1.26-16.79]). Side effect profiles were unchanged from baseline.
Conclusion
Low-dose opioids effectively control severe RLS symptoms over 4-years of observation. Nearly 50% of participants increased their dose, though most changes were small, with larger dose increases associated with specific risk factors.
Support (if any) Thank you to the RLS Foundation, Baszucki Group, and Jerry Blakeley.
Slowly building the evidence