Obesity, physical inactivity appear protective against death
A recent study has found that the obesity paradox only persists in patients who are physically inactive, indicating that physical activity (PA) may be associated with the development of the obesity paradox.
The investigators retrospective analysed a total of 782 patients with implantable cardioverter-defibrillators/cardiac resynchronization therapy defibrillators enrolled in the Study of Home Monitoring System Safety and Efficacy in Cardiac Implantable Electronic Device-Implantable Patients registry. Participants were then grouped by body mass index (BMI): normal weight (BMI, 18.5 to <25 kg/m2) and overweight or class I obesity (BMI, 25 to <35 kg/m2).
The investigators measured PA with home monitoring and categorized this into four groups (Q1 to Q4) by the baseline quartiles.
The primary endpoint of all-cause mortality occurred in 182 patients during a mean follow-up of 59.9±21.9 months. Mortality, however, appeared to be lower in overweight and obesity patients (18.9 percent vs 25.1 percent; p=0.061) and even decreased by PA quartiles (Q1: 44.1 percent; Q2: 33.6 percent; Q3: 15.3 percent; Q4: 11.2 percent; p<0.001).
In multivariate Cox analysis, BMI (hazard ratio [HR], 0.918, 95 percent confidence interval [CI], 0.866–0.974; p=0.004) and PA (Q2 vs Q1: HR, 0.436, 95 percent CI, 0.301–0.631; Q3 vs Q1: HR, 0.280, 95 percent CI, 0.181–0.431; Q4 vs Q1: HR, 0.257, 95 percent CI, 0.158–0.419; p<0.001 for all) correlated with a reduced risk of mortality.
The obesity paradox was significant in the total cohort (log rank p=0.049) and low PA group (log rank p=0.010) but disappeared in the high PA group (log rank p=0.692). Dose-response curves indicated a marked decrease in risk with low–moderate PA, with the pattern varying between different BMI groups.