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BASIC and post-op complications

BASIC – predicting post-op complications after surgery

Of the 24 preoperative variables considered in the univariate analysis as a risk predictor, five were significant

Researchers from Amsterdam, Blaricum and Rotterdam, The Netherlands, who used six pre-operative patient characteristics to classify patients in three risk classes, have concluded that their model identifies a small subgroup of patients with 30.6% risk of overall postoperative complications following bariatric surgery.

The paper, ‘Predicting postoperative complications after bariatric surgery: the Bariatric Surgery Index for Complications, BASIC’, published in the journal Surgical Endoscopy, states that approximately 20% of bariatric surgery patients develop a short- or long-term complication. The aim of the authors was to develop a risk model predicting complications - the Bariatric Surgery Index for Complications (BASIC) - simple, adequate scoring system similar to the obesity surgery mortality risk score (OS-MRS) based on preoperative parameters, assessing the risk on postoperative complications.

The researchers collected data from 1,709 patients who underwent primary or revisional LRYGB or LSG or pouch revision of previous LRYGB between November 2007 and February 2015. For the BASIC score to identify risk factors for complications, class I included patients with zero to one risk factor, class II patients with two risk factors, and class III patients with three or more risk factors.

Complications were scored by both type and severity with the following endpoints: mortality; multi-organ failure; single organ failure; surgical intervention; radiological intervention; medical treatment; no intervention needed; and no complications. In addition, the nature of the complication was scored as well as if it were short-term (occurring within 30 days after surgery) or long-term complications.  Twenty-four patient variables within the database were regarded as possible risk factors and subsequently analysed for postoperative complications.


From November 2007 till February 2015, a total of 1,709 patients underwent bariatric surgery, with primary LRYGB performed in 1,283 patients (75.1%), followed by revision from LAGB into LRYGB in 281 patients (16.4%).

Overall, postoperative complications occurred in 271 patients (15.9%) of which 197 (72.7%) were short-term complications. Twenty-two patients had a leakage of the gastrojejunostomy (GJS), 42 patients suffered from (severe) peri- or postoperative bleeding, 15 patients had a stenosis of the GJS, and ten patients developed an internal herniation approximately 1 year after surgery. Of all 271 complications, 140 patients (8.2% of 1,709) had a severe complication. Five patients (0.3%) in the study died.

Of the 24 preoperative variables considered in the univariate analysis as a risk predictor, five were significant (p<00.05): age of 60>years; hypertension; dyslipidaemia; chronic obstructive pulmonary disease (COPD); and revision from previous bariatric surgery. In the multivariable analysis, backwards selection resulted in elimination of diabetes type II; followed by age above 60; alcohol; corticosteroids; BMI above 50; gastroesophageal reflux disease; smoking; NSAID’s; cholecystectomy; hypertension and history of trombo-embolic event respectively. Consequently, anticoagulant usage; COPD; dyslipidemia; gender; psychiatric history, and revisional surgery provided the most optimal multivariable model. As all factors had an odd’s ratio between the 1.3 and 2.3, one point was assigned to each of the contributing factors.

The researchers divided patients into classes using the variables according to the multivariable analysis and a differentiation was made between short-term and overall complications. The overall complication analysis showed the following results: class I existed of 1,338 (78.3%) patients of which 181 (13.5%) suffered from a complication, class II comprised 269 patients (15.7%) of which 142 (21.6%) patients had a complication and class III existed of 102 patients (6.0%) of which 32 (31.4%) developed a complication. The difference in incidence of complications between the three classes was statistically significant with a p value of 0.001.

Not only was this significant in the occurrence of overall complications but also within the patient group who developed a short-term complication (p = 0.001). These short-term complications occurred in 136 (10.2%) of the patients in class I, 40 (14.9%) patients in class II, and 21 (20.6%) patients in class III, respectively.

The significant difference between classes was mainly caused by the difference between class I and III but the difference between all classes was significant in the overall complication rate. Analyzing short-term complications alone, the significance was mainly caused by comparison of class I and III, followed by I and II. No difference between II and III could be identified. When dividing complications in mild (Clavien-Dindo ≤ 3) and severe (Clavien-Dindo>3) complications, a significant difference exists between class I versus III and class I versus II (Table 1).

Table 1: Select cases between groups

“This study developed a risk model for postoperative complications in an attempt to predict the development of complications after bariatric surgery,” the researchers note. “The study identified six preoperative variables, which are all independent risk factors for the occurrence of postoperative complications. With this risk model, it is possible to select patients with a two times higher risk of postoperative complications compared to the general bariatric population.”

The authors acknowledge that other risk factors, are not analysed in this study, exist and thereby influence the patient outcomes.

“While as of now the BASIC lacks validation, the question can be raised if patients in class III with three or more risk factors should be selected for surgery according to the same eligibility criteria or treated perioperatively under the same conditions as patients from class I or II,” the authors conclude. “Preoperative risk assessment can facilitate patient specific, adjusted care and lead to improved patient outcomes after bariatric surgery.”

This is an open access article distributed under the terms of the Creative Commons Attribution License

To access this paper, please click here

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