Obesity may increase the risks of bleeding and infections after abdominal hysterectomy, but a body mass index (BMI) below 20 kg/m2 also seems to increase the risks of bleeding and infection after abdominal hysterectomy and laparoscopic hysterectomy, respectively, according to the results of an observational cohort study reported online April 5 in Human Reproduction.
“We found that the increased risk of all bleeding complications and infection associated with a high BMI were only seen in women who underwent an abdominal hysterectomy, and it was not seen in those who had either a vaginal or laparoscopic hysterectomy,” said lead author Merete Osler, a consultant physician and professor of clinical databases in the Research Centre for Prevention and Health at Glostrup University Hospital in Glostrup, Denmark, in a news release. “Obese women who had an abdominal hysterectomy had one and a half times the risk compared with women of the recommended BMI.”
The investigators analyzed prospectively collected data regarding health and lifestyle factors from all women referred for hysterectomy for benign indications in Denmark from 2004 to 2009. The association between BMI and complications reported at surgery or during the first 30 days after surgery was evaluated with logistic regression.
Data were complete for 20,353 women, of whom 6.0% had a BMI of less than 20 kg/m2, 31.9% were overweight (BMI 25 – 30 kg/m2), and 17.5% were obese (BMI ≥ 30 kg/m2). The most common specific complication was bleeding, occurring in 6.8% of the whole cohort, and the overall rate of complications was 17.6%.
Obesity was associated with a greater risk of heavy bleeding during surgery (odds ratio [OR], 3.64; 95% confidence interval [CI], 2.90 – 4.56), all bleeding complications (OR, 1.27; 95% CI, 1.08 – 1.48), and infection (OR, 1.47; 95% CI, 1.23 – 1.77), after adjustment for age, ethnicity, educational level, surgical indication, uterine weight, use of prophylaxis, American Society of Anesthesiologists classification, comorbid conditions, and route of hysterectomy.
Women with a BMI of less than 20 kg/m2 also had an increased risk of all bleeding complications (OR, 1.48; 95% CI, 1.28 – 1.82) and subsequent surgery (OR, 1.66; 95% CI, 1.26 – 2.17), with this U-shaped association between BMI and bleeding, and between high BMI and infections, seen only for abdominal hysterectomy. However, women with a BMI of less than 20 kg/m2 undergoing laparoscopic hysterectomy also had an increased risk for infections.
“Low BMI does appear to be a risk factor,” Prof. Osler said. “Interestingly, being overweight, with a BMI between 25 – 30 does not seem to be associated with increased risks, apart from heavy bleeding where there is a two-fold risk. In fact, overweight women seem to have the lowest risk of all complications and re-hospitalisation and re-operation.”
Limitations of this study include data on BMI and several other covariates missing for approximately 8% of the women. Data were mostly missing from a few private hospitals, possibly limiting generalizability to these groups.
“Our results suggest that, whenever possible, obese women should have a vaginal or laparoscopic hysterectomy for benign indications, while underweight women should have a vaginal hysterectomy, in order to avoid the increased risks identified in our study,” Prof. Osler concluded.
The study authors have disclosed no relevant financial relationships.
Hum Reprod. Published online April 5, 2011. Abstract
— Laurie Barclay, MD0