Peri-operative Risk Factors for 30-day Mortality After Bariatric Surgery: Is Functional Status Important?

Muhammad Asad Khan, MD, Roman Grinberg, MD, Stelin Johnson, RPAC, John N Afthinos, MD, Karen E Gibbs, MD. Staten Island University Hospital

 

OBJECTIVE:

Although mortality from bariatric surgery is low, peri-operative determinants of morbidity and mortality in this population have yet to be fully defined. Our aim was to evaluate the factors capable of predicting perioperative mortality based on preoperative characteristics with a national patient sample.

METHODS:

Using the ACS-NSQIP database, we identified all primary bariatric procedures performed between 2007 and 2009. Using univariate analysis, factors associated with increased perioperative (30-day) mortality were identified. Logistic regression and the jackknife procedure were used to select correlates of 30-day mortality that were subsequently weighted and integrated into an integer scoring system based on the number of co-morbid risk factors.

RESULTS:

We identified 44,408 patients (79% female and 21% male) with mean age of 45 ± 11 years. Cumulative 30 day peri-operative mortality was 0.14%. The majority of procedures performed included laparoscopic gastric bypass (54%) followed by laparoscopic gastric banding (33%) and open gastric bypass (7%). Independent predictors associated with significantly increased mortality included age > 45 (Adjusted odds ratio, AOR=2.45), male gender (AOR=1.77), BMI ≥50 kg/m2 (AOR=2.48), open bariatric procedures (AOR=2.34), diabetes (AOR=2.88), totally dependent functional status prior to surgery (AOR=27.6), prior coronary intervention (AOR=2.66), dyspnea on preoperative evaluation (AOR=4.64), > 10% weight loss in 6 months (AOR=13.5) and bleeding disorder (AOR=2.63). Ethnicity, hypertension, alcohol abuse, liver disease and smoking had no significant association with mortality in this study. Risk stratification based on number of preoperative co-morbid factors revealed an exponential increase in mortality: 0.03% (0-1 comorbidities), 0.16% (2-3 comorbidities) and 7.4% (4 or greater comorbidities). This system provides excellent prognostic accuracy in the study population (c-statistics = 0.74).

CONCLUSION:

This model provides a straightforward, precise and easily applicable tool to identify bariatric patients at low, intermediate and high risk for in-hospital mortality. Of note, baseline functional status prior to surgery is the single most powerful predictor of peri-operative survival and should be incorporated into risk stratification models.
 


Session Number: SS09 – Obesity Surgery
Program Number: S053

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