Methods National audit of a 90-day prospective observational cohort in which pre-defined postoperative complications were analyzed at 30 days of follow-up in adult patients undergoing elective bariatric surgery with or without an intensified recovery program (ERAS: Enhanced Recovery after Surgery) with any level of protocol compliance (0-100%)

Research Places Spanish Hospitals where this surgical intervention is carried out.

Objectives To determine the incidence of postoperative complications per patient and procedure, regardless of the degree of adherence to ERAS protocols and its impact on the hospital stay and postoperative complications including 30-day mortality.

Sample size For an alpha error of 5% (95% confidence) and an accuracy of 3% and estimating a number of patients with complications of 11%, the sample size calculation yields 460 patients, although the final sample size it may be smaller depending on the proportion of complications detected.

Inclusion criteria Patients older than 18 years who are going to be electively operated on for bariatric surgery regardless of their adherence to an ERAS intensified recovery program and the compliance level of the protocol (from 0-100%)

Statistical analysis Continuous variables will be described as mean and standard deviation, if it is a normal distribution, or median and interquartile range, if they are not normally distributed. Comparisons of continuous variables will be performed by one-way ANOVA or the Mann-Whitney test, as appropriate. A univariate analysis will be performed to test the factors associated with postoperative complications, hospital stay and death in the hospital. Univariate analyzes and hierarchical multivariate logistic regression models will be constructed to identify factors associated independently with these results and to adjust for differences in confounding factors. The factors will be introduced in the models based on their relationship with the univariate result (p <0.05), the biological plausibility and the low rate of missing data.

The results of this study will allow to identify, on the one hand, the type of patients presenting postoperative complications and, on the other hand, to identify those items of the ERAS protocols that are independently associated with a reduction in postoperative complications and hospital stay, which will allow to focus the perioperative efforts in those items that actually improve the postoperative outcomes.

Aim 1 will establish the number of patients developing predefined postoperative complications within 30 days of surgery in adult patients undergoing elective bariatric surgery with any compliance of an ERAS protocol (including patients with 0 compliance). This will allow us to determine the actual impact of these protocols.

Aim 2 will allow us to know the type of predefined complication presented by the patients included in the ERAS protocols and in patients undergoing bariatric surgery; This will allow, on the one hand, to have a starting point for future clinical trials, and, on the other hand, to focus efforts to avoid these complications.

Aim 3 will allow us to identify those perioperative items of ERAS protocols that are actually associated with a decrease in postoperative complications.

The proposed study will establish a real view of the number of patients presenting postoperative complications that will overcome the limitations of available retrospective studies and provide greater insight into the items of the protocols that are associated with decreased complications; on the other hand, the investigator's hypothesis is that the number of patients who develop predefined postoperative complications within 30 days of surgery decreases as there is greater compliance with the predefined ERAS protocol items

Inclusion Criteria:

• All adult patients (aged ≥18 years) undergoing elective bariatric surgery and by any approach (Includes surgery with laparoscopic, assisted laparoscopic approach or open approach) in a participating hospital during the 30-day cohort period with a planned overnight stay.

Exclusion Criteria:

• Patients undergoing emergency surgery

  • Endoscopic procedures
  • Patients under 18 years of age
  • Patients with previous bariatric surgery who undergo revision surgery
  • Patients who refuse to participate

Adult patients (aged ≥18 years) undergoing elective bariatric surgery