Both obese and underweight patients undergoing ventral hernia repair have a significantly greater risk of complications, particularly if they have strangulated/reducible hernias, according to data published online in Surgery.
In a retrospective analysis, researchers examined data from 102,191 patients – 58.5% of whom were obese – who underwent ventral hernia repair, and found a J-shaped curve in the association between complication rates and body mass index.
Underweight patients with a BMI less than 18.5kg/m2 had a 10% risk of complications, while those of normal BMI (18.5-24.99) had the lowest complication risk: 7.7%. Complication rates then increased steadily with increasing BMI; 8.2% for overweight patients, 9.7% for the obese, 12.2% for the severely obese, 16.1% for the morbidly obese, and 19.9% for the super obese (Surgery 2017, Sep 27. ).
Analysis by individual medical complications showed that postoperative pneumonia, pulmonary embolism, acute renal failure, and urinary tract infection were all statistically significantly more common with increasing BMI. The risk of myocardial infarction did not differ significantly with BMI.
The researchers also examined the effects of different hernia types. The 70.3% of patients who had reducible hernias had lower complication rates overall, as well as lower rates of complications in each category of operative, medical, and respiratory, compared with the 29.7% of patients with strangulated/incarcerated hernias.
Nearly one-quarter of the patients in the study were undergoing recurrent ventral hernia repair, and these patients were more likely to have a higher BMI.
After taking into account variables such as age, smoking comorbidities, type of hernia, and type of repair, the authors concluded that the odds of having any complication increased significantly above a BMI of 30 kg/m2, using normal weight BMI as a reference. The odds were 22% higher in those with BMIs in the 30-34.99 range, 54% higher for those in the 35-39.99 range, twofold higher for those with a BMI between 40 and 50, and 2.6-fold higher above 50 kg/m2.
“Surgeons are presented with increasing numbers of obese patients, and the best way to manage ventral hernias in this population remains unclear,” the authors wrote, although they raised the possibility that laparoscopic procedures reduce the risk of some complications.
“Although the majority of VHRs performed utilize an open technique, studies have found decreased duration of stay, morbidity, and, in selected studies, even decreased recurrence using the laparoscopic approach.”
No conflicts of interest were declared.