Synergistic effect of age and body mass index on mortality and morbidity in general surgery.

BACKGROUND: The elderly population (aged 65 y and older) is expected to be the dominant age group in the United States by 2030. In addition, the prevalence of obesity in the United States is growing exponentially. Obese elderly patients are increasingly undergoing elective or emergent general surgery. There are few, if any, studies highlighting the combined effect of age and body mass index (BMI) on surgical outcomes. We hypothesize that increasing age and BMI synergistically impact morbidity and mortality in general surgery. MATERIALS AND METHODS: We collected individual-level, de-identified patient data from the Michigan Surgical Quality Collaborative. Subjects underwent general surgery with general anesthetic, were >18 y, and had a BMI between 19 and 60. Primary and secondary outcomes were 30-d "Any morbidity" and mortality (from wound, respiratory, genitourinary, central nervous system, and cardiac systems), respectively. Preoperative risk variables included diabetes, dialysis, steroid use, cardiac risk, wound classification, American Society of Anesthesiology class, emergent cases, and 13 other variables. We conducted binary logistic regression models for 30-d morbidity and mortality to determine independent effects of age, BMI, interaction between both age and BMI, and a saturated model for all independent variables. RESULTS: We identified 149,853 patients. The average age was 54.6 y, and the average BMI was 30.9. Overall 30-d mortality was 2%, and morbidity was 6.7%. Age was a positive predictor for mortality and morbidity, and BMI was negatively associated with mortality and not significantly associated with morbidity. Age combined with higher BMI was positively associated with morbidity and mortality when the higher age groups were analyzed. Saturated models revealed age and American Society of Anesthesiology class as highest predictors of poor outcomes. CONCLUSIONS: Although BMI itself was not a major independent factor predicting 30-d major morbidity or mortality, the morbidly obese, elderly (>50 and 70 y, respectively) subgroup may have an increased morbidity and mortality after general surgery. This information, along with patient-specific factors and their comorbidities, may allow us to better take care of our patients perioperatively and better inform our patients about their risk of surgical procedures.

Outcomes of diabetic and nondiabetic patients undergoing general and vascular surgery.

Aims. Preoperative diabetic and glycemic screening may or may not be cost effective. Although hyperglycemia is known to compromise surgical outcomes, the effect of a diabetic diagnosis on outcomes is poorly known. We examine the effect of diabetes on outcomes for general and vascular surgery patients. Methods. Data were collected from the Michigan Surgical Quality Collaborative for general or vascular surgery patients who had diabetes. Primary and secondary outcomes were 30-day mortality and 30-day overall morbidity, respectively. Binary logistic regression analysis was used to identify risk factors. Results. We identified 177,430 (89.9%) general surgery and 34,006 (16.1%) vascular surgery patients. Insulin and noninsulin diabetics accounted for 7.1% and 9.8%, respectively. Insulin and noninsulin dependent diabetics were not at increased risk for mortality. Diabetics are at a slight increased odds than non-diabetics for overall morbidity, and insulin dependent diabetics more so than non-insulin dependent. Ventilator dependence, 10% weight loss, emergent case, and ASA class were most predictive. Conclusions. Diabetics were not at increased risk for postoperative mortality. Insulin-dependent diabetics undergoing general or vascular surgery were at increased risk of overall 30-day morbidity. These data provide insight towards mitigating poor surgical outcomes in diabetic patients and the cost effectiveness of preoperative diabetic screening.