Central obesity linked to recurrent heart events in sleep apnea patients
A post hoc analysis of the SAVE trial (n=2,662 adults with moderate-to-severe obstructive sleep apnea and established cardiovascular disease) found that waist-to-height ratio—a measure of central adiposity—was associated with recurrent cardiovascular events over 3.7 years, while conventional BMI was not.
In a large international randomized trial of 2,662 adults with co-occurring obstructive sleep apnea (OSA) and established cardiovascular disease, researchers examined how different measures of body fat distribution predicted recurrent heart attacks, strokes, and related events over 3.7 years of follow-up. Participants were either randomized to CPAP (continuous positive airway pressure) treatment plus usual care or usual care alone.
While 31.8% were classified as obese by conventional BMI (≥30 kg/m²), 95.6% had central adiposity defined by a waist-to-height ratio ≥0.50. Using Cox regression, the researchers found that waist-to-height ratio showed a clear dose-dependent association with composite cardiovascular events (p=0.0187), with those in the highest ratio quartile carrying a 52% higher risk than the lowest quartile (hazard ratio 1.52, 95% CI 1.12–2.05). In contrast, conventional BMI categories showed no clear linear relationship with recurrent CVD events, suggesting that standard weight-based classifications may mask true cardiovascular risk in this population. CPAP treatment effects on outcomes did not differ by baseline adiposity measures. This finding highlights that in patients with OSA and heart disease, abdominal fat distribution—captured by waist-to-height ratio—may be a stronger predictor of future cardiovascular events than overall body weight alone.
The nonlinear relationship between BMI and recurrent CVD events in this population is telling: conventional weight thresholds alone may not identify high-risk individuals in OSA patients with established heart disease. The waist-to-height ratio, a simple bedside measure, discriminated risk far more clearly—each increase in central adiposity quartile substantially elevated event risk. Notably, 95.6% of this already-sick population had central adiposity, meaning traditional obesity classifications missed almost all of them; only BMI picked up 31.8%. The SAVE trial's intervention (CPAP) showed similar cardiovascular benefit regardless of baseline adiposity level, suggesting that treating sleep apnea itself remains important across body-fat phenotypes. Limitations include the post hoc design (these associations were secondary outcomes, not prespecified), the absence of competing-risk adjustment (participants could have died before a CVD event, altering incidence estimates), and the 3.7-year window (longer follow-up might reveal different adiposity-risk patterns). The mechanistic link may involve visceral fat driving inflammation and metabolic dysfunction independent of overall BMI.
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Open in Cadence →References
- Central Obesity and Recurrent Cardiovascular Events in Patients With Obstructive Sleep Apnea: The SAVE Study. — Neurology (Read the original)