Is weight trajectory a better marker of wound complication risk than BMI in hernia patients with obesity?

Complex ventral hernias are frequently repaired via an open transversus abdominis release (TAR). Obesity, particularly a BMI > 40, is a strong predictor of wound morbidity following this procedure. We aimed to determine if preoperative weight loss may still be beneficial in patients with persistently elevated BMIs.

A retrospective chart review of patients with obesity (BMI ≥ 30) who underwent open TAR at a tertiary academic medical center from January 2018 to December 2021 was completed. Demographics, medical history, operative details, and postoperative data were analyzed. Weight and BMI were recorded at three time points: > 6 months prior to initial surgical consultation, surgical consultation, and day of surgery.

In total, 182 patients with obesity underwent an open TAR. Twenty-seven patients (14.8%) underwent surgery with a BMI > 40; they did not have any significant differences in surgical site occurrences (SSO, 48.1% vs 32.9%, p = 0.13) or surgical site infections (SSI, 25.9% vs 23.2%, p = 0.76) compared to those with a BMI ≤ 40. The average timeframe analyzed for preoperative weight loss was 592 days. Patients who had at least a 3% weight loss (n = 49, 26.9%) had decreased rates of SSI compared to those who did not have this weight loss (12.2% vs 27.8%, p = 0.03), despite the groups having similar BMIs at the time of surgery (36.4 vs 36.0, p = 0.50). Patients who only had a 1% weight loss did not see a decrease in SSI rate compared to those who did not (20.6% vs 25.4%, p = 0.45).

Weight loss may be a better indicator of a patient's risk for wound morbidity following TAR than BMI alone, as weight loss of at least 3% resulted in fewer SSIs despite similar BMIs at time of surgery. Further research into optimal timing and amount of weight loss, as well as effects on long-term outcomes, is needed to confirm these findings.