[Association between Bariatric Surgery and Cardiorespiratory Fitness: A 15-Year Retrospective Study in Chile]

Cardiorespiratory fitness is a modifiable risk factor and can be used to screen the bariatric patient.

To evaluate the association between the type of bariatric surgery and cardiorespiratory fitness in patients with obesity over a 15-year period.

Clinical records with socio-demographic and health data of 594 adults of both genders who were candidates for bariatric surgery from a state hospital in Chile were analysed. Fitness was calculated using an equation before the surgical procedure. The sample was divided according to BMI quartiles, and logistic regression (odds ratio [OR]) with 95% confidence intervals (CI) and models without and with adjustment for confounding variables (socio-demographics, lifestyle factors, and comorbidities) were used to assess the association between bariatric surgery and fitness.

In the sample, if V·O2max increased by one unit (mlO2/kg/min) the probability of gastric sleeve surgery decreased by 4% (OR: 0.96 [CI: 0.93, 0.99], p= 0.034), and adjusted for socio-demographic variables it decreased by 5% (OR: 0.95 [CI: 0.91, 0.98], p= 0.009). In women, this probability would decrease by 5-9% (p<0.05) in the models without and with adjustment for confounding variables. Meanwhile, for the lowest quartile of BMI (≤38.09 kg/m2) if V·O2max increased by 1 mlO2/kg/min patients would be 15.7% more likely to undergo gastric sleeve surgery when adjusting for comorbidities (OR: 1.157 [CI: 1.004, 1.33], p= 0.044). The study was retrospective and cross-sectional, as it does not allow for establishing causal relationships between V·O2max and the type of surgery.

An increase in V·O2max reduced the odds of gastric sleeve surgery independent of confounding variables in the total sample and in women. In addition, the lowest quartile of BMI had higher odds of operation as long as the V·O2max increased when adjusting for comorbidities.