Patient Age at Gastric Bypass Surgery and Mortality
What is the impact of age on efficacy of bariatric surgery in reducing all-cause and cause-specific long-term mortality?
All-cause and cause-specific mortality rates and hazard ratios (HRs) were estimated from a retrospective cohort within four categories defined by age at surgery: younger than 35 years, 35-44 years, 45-54 years, and 55-74 years. Mean follow-up was 7.2 years. Patients undergoing Roux-en-Y gastric bypass surgery were studied. A cohort of 7,925 patients undergoing gastric bypass surgery and 7,925 group-matched, severely obese individuals who did not undergo surgery were identified through driver license records. Matching criteria included year of surgery to year of driver license application, sex, 5-year age groups, and three body mass index categories. The main outcome measures were all-cause and cause-specific mortality compared between those undergoing and not undergoing gastric bypass surgery using HRs.
Among the 7,925 patients who underwent gastric bypass surgery, the mean (standard deviation [SD]) age at surgery was 39.5 (10.5) years, and the mean (SD) presurgical body mass index was 45.3 (7.4) kg/m2. Compared with 7,925 matched individuals not undergoing surgery, adjusted all-cause mortality after gastric bypass surgery was significantly lower for patients 35-44 years old (HR, 0.54; 95% CI, 0.38-0.77), 45-54 years old (HR, 0.43; 95% CI, 0.30-0.62), and 55-74 years old (HR, 0.50; 95% CI, 0.31-0.79; p < 0.003 for all), but was not lower for those younger than 35 years (HR, 1.22; 95% CI, 0.82-1.81; p = 0.34). The lack of mortality benefit in those undergoing gastric bypass surgery at ages younger than 35 years primarily derived from a significantly higher number of externally caused deaths (HR, 2.53; 95% CI, 1.27-5.07; p = 0.009), particularly among women (HR, 3.08; 95% CI, 1.4-6.7; p = 0.005). Patients undergoing gastric bypass surgery had a significantly lower age-related increase in mortality than severely obese individuals not undergoing surgery (p = 0.001).
The authors concluded that gastric bypass surgery was associated with improved long-term survival for all patients undergoing surgery at ages older than 35 years, with externally caused deaths only elevated in younger women.
This study reports that the increased mortality from external causes in patients undergoing gastric bypass surgery was limited to the subgroup of women who underwent surgery before 35 years of age. Furthermore, the data suggest that gastric bypass surgery is protective against mortality even for patients who undergo surgery at an older age. Gastric bypass surgery also reduces the age-related increase in mortality risk compared with those obese individuals who do not undergo surgery. It appears that young women in particular are a vulnerable population who may need additional preoperative evaluation and postoperative follow-up to limit potentially avoidable causes of death. In general, clinicians need to be judicious in the workup, selection, and postoperative follow-up of both young and old patients undergoing gastric bypass surgery.
Keywords: Age Factors, Bariatric Surgery, Gastric Bypass, Metabolic Syndrome X, Mortality, Obesity, Outcome Assessment (Health Care), Primary Prevention, Risk
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