D97-07 Long-term Conditioning Response After Positional Therapy Withdrawal in Obstructive Sleep Apnea: The Pavlov Randomized Controlled Trial

Rationale Positional obstructive sleep apnea (POSA) affects 56%-75% of patients with OSA. While CPAP is effective, limited adherence makes positional therapy a promising alternative offering both efficacy and better tolerance. In the original analysis of our randomized controlled trial (Pávlov Study, NCT05268471), we demonstrated a significant conditioning effect after one month of withdrawal of positional therapy. However, the persistence of this effect and its potential long-term impact remain uncertain. Objectives To evaluate whether the Pavlovian conditioning response observed one month after withdrawal of positional therapy, persists up to one year in patients with POSA who previously responded to treatment. Methods Patients diagnosed with POSA by respiratory polygraphy (RP) were randomized to treatment with a PD (NightBalance, Philips) or CPAP. After six months of therapy, RP was repeated using the assigned device. In patients who responded to treatment (residual AHI <15 events/hour and ≥50% reduction from baseline), PD or CPAP was discontinued, and RP was subsequently repeated after 1 week, 1 month, 3 months, and 1 year to determine whether responder status was maintained in the absence of device use. Results A total of 184 patients with POSA were included. After treatment withdrawal, 19 of 56 (33.9%) patients in the CPAP group maintained responder status at 1 week, decreasing to 7 of 17 (41.2%) at 1 month, and 0% at 3 months according to RP. In contrast, among those treated with the PD therapy, 37 of 47 (78.7%) maintained responder status at 1 week, 31 of 35 (88.6%) at 1 month, and 19 of 23 (82.6%) at 3 months after PD withdrawal. The nineteen PD responders at 3 months were eligible for 1-year follow-up. Among them, 13 of 19 (68.4%) maintained responder status, 2 (10.5%) no longer met responder criteria, and 4 (21.0%) were lost to follow-up. Conclusions One year after treatment discontinuation, more than two-thirds of PD-treated responders maintained POSA control without ongoing device use, supporting the hypothesis of a long-term Pavlovian effect. These findings highlight the potential of positional therapy not only as an effective and better-tolerated alternative to CPAP but also as a modality capable of inducing long-term behavioral change in sleep position.