Weight · OSA · GLP-1

GLP-1 agents, tirzepatide, and sleep apnoea

Written by Dr Ari Manuel, Consultant in Sleep & Respiratory Medicine

The arrival of effective pharmacological weight management — and in particular the dual GIP/GLP-1 agonist tirzepatide (Mounjaro) — has meaningfully changed the clinical conversation around obesity-related sleep-disordered breathing. For the first time, substantial and sustained weight loss is achievable without surgery in a broad population, and the respiratory consequences are significant.

What the SURMOUNT-OSA trial showed

The SURMOUNT-OSA trial demonstrated that tirzepatide produced clinically meaningful reductions in AHI in adults with moderate-to-severe OSA and obesity — with a proportion of participants achieving remission by conventional diagnostic criteria. These results have prompted regulatory approval of tirzepatide for OSA in some jurisdictions, and reframed how we think about the interaction between pharmacological weight management and device therapy.

What this means in practice

Patients on GLP-1 agents who achieve significant weight loss may find their device settings need adjustment, or that less intensive therapy is required. This requires formal reassessment — CPAP should not be stopped without objective measurement. Conversely, for patients with OHS, weight loss may reduce or normalise ventilatory requirements, but again only reassessment with appropriate testing can confirm this safely.

My published work in Sleep (2025) specifically addressed how GLP-1 receptor agonists and SGLT2 inhibitors affect serum bicarbonate — a commonly used OHS screening marker — and why clinicians need to be aware of this interaction to avoid missing or misclassifying OHS in patients on these agents.

Where clinically appropriate, we can advise on and support referral for GLP-1 agent prescribing as part of an integrated assessment. This requires proper clinical eligibility assessment and should be managed with specialist oversight.