What is the BMI threshold for open ventral hernia repair?

Overweight and obese patients are often asked to lose weight prior to ventral hernia repair (VHR). Improved outcomes are the reasons behind this strategy. Data regarding weight loss targets are scant, and it is not known at what body mass index (BMI) threshold postoperative complications increase. This study aimed to determine the threshold to allow proper patient counseling.

All patients who underwent open VHR at our institution between 2002 and 2015 captured in the NSQIP database were included. The primary outcome was defined as any (≥1) of 18 captured postoperative complications. Patients were divided into five groups based on BMI: group 1 (<25 kg/m²); 2 (25-29.99 kg/m²); 3 (30-34.99 kg/m²); 4 (35-39.99 kg/m²); and 5 (≥40 kg/m²). Multivariable, adjusted logistic regression was performed to evaluate the association between BMI categories and postoperative complications.

Sixty seven of 922 patients (7.3 %) had at least one postoperative complication following VHR. The adjusted odds of complications in group 5 was 2.89 times greater compared to group 1 (OR 2.89; 95 % CI = 1.22-6.84), while there was no significant differences in odds of postoperative complications for groups 2, 3, or 4 compared to group 1. BMI category was also significantly associated with undergoing recurrent VHR, with 28.7 % of patients in group 5 having a recurrent repair compared to 14 % in patients in group 1 (p = 0.03).

After VHR, complications are most likely to occur in patients with BMI ≥ 40 kg/m². This subset of patients also had a significantly higher risk of undergoing surgery for a recurrent hernia, suggesting that this group of patients is likely to experience adverse outcomes after VHR and should be counseled to consider bariatric surgery prior to attempts at VHR. VHR at lower BMIs appears appropriate, and delaying therapy to achieve preoperative weight loss will likely offer no advantage.