Impact of Bariatric Surgery on Heart Failure Exacerbations
Is bariatric surgery associated with decreased rate of heart failure (HF) exacerbation?
The investigators performed a self-controlled case series of obese HF patients who underwent bariatric surgery. They utilized population-based emergency department (ED) and in-patient data. The primary outcome was an ED visit or hospitalization for HF exacerbation. The secondary outcomes were an ED visit with HF exacerbation and hospitalization with HF exacerbation assessed separately. They used conditional logistic regression to compare the outcome event rate during sequential 12-month periods, using presurgery months 13-24 as the reference period.
The study cohort was comprised of 524 HF patients who underwent bariatric surgery during the reference period of 2005-2011. The investigators found that 16.2% (95% confidence interval [CI], 0.67-1.30) of the cohort had an ED visit or a hospitalization for HF exacerbation. This remained the same in the subsequent 12-month presurgery period at 15.3% (95% CI, 12.2%-18.4%) with a corresponding odds ratio of 0.93 (95% CI, 0.67-1.30; p = 0.067). In the first 12-month period after bariatric surgery, they found a reduced rate of 12% (95% CI, 9.2%-14.8%), although it did not reach significance corresponding to adjusted odds ratio of 0.71 (p = 0.052). They found a significantly lower rate in the second year after surgery at 9.9% (adjusted odds ratio, 0.57; 95% CI, 0.39-0.82; p = 0.003), whereas there was no significant reduction rate of HF exacerbation for obese patients who underwent nonbariatric surgery such as hysterectomy or cholecystectomy.
The authors concluded that their data suggest bariatric surgery reduces HF exacerbations in obese patients.
This is an important study because it suggests weight loss has a beneficial effect in that it reduces HF exacerbations. The mechanism is probably due to the fact that weight loss also has a beneficial effect on cardiovascular hemodynamics. Or alternatively, it could possibly be due to the fact that patients who undergo bariatric surgery are a more motivated group, and as they lose weight, they are even more committed to better health and dietary compliance. In addition, almost always bariatric surgery patients undergo dietary counseling prior to surgery, making them more aware and therefore possibly more committed to complying with dietary and other therapeutic recommendations. As the authors point out, further studies are required to determine the mechanism by which bariatric surgery has beneficial effects of HF exacerbation.
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