In general, COVID-19 statistics point to markedly low mortality among patients younger than 60. But is the protective effect of youth negatively affected by obesity? Researchers used the American Heart Association's COVID-19 Cardiovascular Disease Registry to examine the effect of obesity across different age groups on mortality, receipt of mechanical ventilation, or both.
The strongest association between BMI and death or mechanical ventilation was seen in participants aged 50 or younger. Stage III obesity was associated with excess risk for in-hospital death in those 50 or younger, but not in those older than 50. Crude mortality rates were 3.3% (Class I), 5.0% (Class II), and 8.3% (Class III) in patients aged ≤50.
This study confirms that obesity confers excess risk for hospitalisation, mechanical ventilation, and death from COVID-19 — and shows, for the first time, that the adverse effects of obesity on COVID-19 outcomes may be limited to people under 50 (rather than compounding such risks in older persons). The reasons are likely multifactorial, including comorbidities such as diabetes mellitus, hypertension, and cardiovascular disease, delays in seeking care, and even the possibility of adipocytes serving as viral reservoirs. These findings should serve not only as a wake-up call to younger obese patients, but also as a guidepost for vaccine allocation to high-risk groups.