Respiratory Trials·org

Topic

Sleep medicine

CPAP and its cardiovascular endpoints, hypoventilation, and weight-loss pharmacotherapy.

CPAP treats symptoms, not cardiovascular risk. In patients with moderate-to-severe obstructive sleep apnoea and established cardiovascular disease, CPAP abolished the apnoea — the AHI fell from 29 to under 4 — and did not reduce cardiovascular events over 3.7 years (SAVE). The same was found in non-sleepy patients (Barbe 2012). Both trials are limited by adherence of around three hours a night, and neither challenges CPAP for the symptomatic patient, which remains its clear indication.

Two alternatives to the mask. Hypoglossal nerve stimulation cut the AHI by two thirds, in an uncontrolled cohort of selected, relatively slim patients (STAR) — a real option for CPAP intolerance rather than an equivalent. More striking, tirzepatide halved the AHI in obese patients while lowering weight, hypoxic burden, blood pressure and hsCRP (SURMOUNT-OSA), reframing obesity-related apnoea as a treatable metabolic disease.

Adaptive servo-ventilation is the cautionary tale of the field. In heart failure with reduced ejection fraction and predominantly central apnoea, it suppressed the apnoeas exactly as designed — AHI 6.6 — and increased both all-cause and cardiovascular mortality (SERVE-HF). Correcting a physiological abnormality is not the same as helping the patient.

Does CPAP prevent cardiovascular events?

Trial Year Therapy Effect Finding
SAVE 2016 CPAP CPAP did not prevent cardiovascular events, though it treated the apnoea and improved symptoms
Barbe 2012 2012 CPAP CPAP did not significantly reduce incident hypertension or cardiovascular events in non-sleepy OSA

Central sleep apnoea in heart failure

Trial Year Therapy Effect Finding
SERVE-HF 2015 Adaptive servo-ventilation Adaptive servo-ventilation abolished the central apnoeas and increased mortality

Device alternatives to CPAP

Trial Year Therapy Effect Finding
STAR 2014 Upper-airway stimulation Hypoglossal nerve stimulation cut the AHI by two thirds — in an uncontrolled cohort

Treating the obesity rather than the airway

Trial Year Therapy Effect Finding
SURMOUNT-OSA 2024 Tirzepatide Tirzepatide halved the apnoea-hypopnoea index in obese patients with OSA

Key references

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