Assessing Risk of Critical Care Complications and Mortality in the Elective Bariatric Surgery Population Using a Modified Frailty Index

Document Type


Publication Date


Publication Title

Obesity surgery : the official journal of the American Society for Bariatric Surgery and of the Obesity Surgery Society of Australia and New Zealand


BACKGROUND: The rate of surgical complications from bariatric procedures remains low despite an increase in volume. When serious complications occur, they are associated with an increased risk of mortality. The aim of this study is to determine if frail bariatric patients have an increased rate of Clavien level 4 and 5 complications. This study was conducted in participating hospitals in the National Surgical Quality Improvement Program (NSQIP).

METHODS: The NSQIP participant use files were used to identify 104,952 patients undergoing elective bariatric procedures from 2005 to 2012. A previously described modified frailty index (mFI) was calculated based on available NSQIP variables, with a higher index suggesting more frail patients. Postoperative adverse events were stratified to Clavien levels 4 and 5 utilizing a pre-existing mapping scheme.

RESULTS: Overall, 1 % of patients undergoing elective bariatric surgery experienced Clavien level 4 complications, and 0.2 % experienced a Clavien level 5 complication (mortality). Univariate analysis demonstrated that frailty was significant for both Clavien level 4 and 5 complications (p < 0.001). The mean mFI for those with Clavien level 4 complications, 0.15, was significantly higher than those without Clavien 4 complications, 0.09 (p < 0.001). Those experiencing mortality had a mean mFI of 0.17 compared to a mean mFI of 0.09 in those without mortality (p < 0.001). Frailty retained the highest odds ratio for both Clavien 4 and 5 complications in multivariate analysis compared to American Society of Anesthesiologist (ASA) class, age, sex, body mass index (BMI), and procedure type.

CONCLUSIONS: Frailty may be used during patient selection to stratify bariatric surgery patients at high risk for critical care level complications.

Medical Subject Headings

Adult; Aged; Bariatric Surgery; Critical Care; Elective Surgical Procedures; Female; Frail Elderly; Humans; Male; Middle Aged; Multivariate Analysis; Obesity, Morbid; Odds Ratio; Postoperative Complications; Risk Assessment; Severity of Illness Index; Survival Analysis

PubMed ID






First Page


Last Page