Impact of Preoperative Anemia on Postoperative Kidney Function Following Laparoscopic Bariatric Surgery

Renal Function Following Bariatric Surgery: a Literature Review of Potential Mechanisms

Obesity is a major and independent risk factor for onset and progression of many renal diseases. Bariatric surgery (BS) improves renal function by improving obesity-related metabolic disorders. However, the procedure is also accompanied by renal risks, including acute kidney injury (AKI) and oxalate nephropathy. Here, we briefly review the history and principle of frequently applied technique for BS and summarize the comprehensive BS effect on kidney function. Importantly, we highlight the possible molecular mechanisms associated with the recovery of renal function to provide novel ideas for future studies and clinical applications.

The role of preoperative anemia in patients undergoing colectomy for diverticular disease: does surgical urgency matter?

PURPOSE

Surgery especially in the emergent setting carries higher rates of morbidity and mortality. The aim of our study was to evaluate the impact of preoperative anemia on outcomes for patients undergoing colectomy for acute diverticulitis in both elective and emergent settings.

METHODS

We performed a 4-year analysis of the ACS-NSQIP and included adult patients with acute diverticulitis who underwent colectomy. Patients were stratified into two groups based on preoperative hemoglobin levels, preop anemia and no-preop Anemia. Outcome measures were 30-day complications, anastomotic leaks, readmissions, mortality, and intra-/postoperative blood transfusion. We also performed a sub-analysis for patients who underwent emergent colectomy.

RESULTS

Six thousand nine hundred sixty-three patients were included in the analysis, of which 37% (n = 2571) had preoperative anemia. Patients in the anemia group were more likely to have higher ASA class and receive blood 72-h preoperatively (5.4% vs. 0.2%, p < 0.01). Patients in the anemia group had higher rates of complications (35.4% vs. 24.7%, p < 0.01), unplanned readmission (9.2% vs 7.2%, p < 0.01), mortality (4.5% vs. 1.8%, p < 0.01), and intra/postoperative transfusion requirement (21% vs. 3.8%, p < 0.01) with no difference in rate of anastomotic leaks. On sub-analysis, 39% of the cases were completed in an emergent setting, 85% of which were due to perforation. Patients with preoperative anemia that underwent colectomy in an emergent setting had higher odds of intra/postoperative blood transfusion (OR 51.6, CI 3.87-6.87, p < 0.01) with no statistical significance in 30-day complications (p = 0.51).

CONCLUSION

Preoperative anemia in patients undergoing colectomy for acute diverticular disease is associated with higher odds complications, readmissions, and intra/postoperative blood transfusions.

Which Factors Are Associated with a Higher Prevalence of Anemia Following Bariatric Surgery? Results from a Retrospective Study Involving 1999 Patients

INTRODUCTION

Anemia in obese patients is common and multifactorial and is also a complication of bariatric surgery. The aim of this study is to establish which variables are associated with a higher prevalence of post-bariatric surgery anemia.

METHODS

Retrospective cohort study involving 1999 patients submitted to bariatric surgery with a follow-up period of 4 years. Anthropometric, laboratorial parameters and the presence of comorbidities were evaluated before surgery and during follow-up. Patients were divided into two groups, according to whether they developed anemia, or not. Groups were compared using independent sample T-tests or Chi-squared tests, as appropriate. Univariate binary logistic regression models were used to test the association between the diagnosis of anemia during follow-up and all the possible explanatory variables. Independent variables with an association with the outcome (p < 0.1) were included in multivariate binary logistic regression models, as well as possible confounders (age, BMI, and supplementation).

RESULTS

Anemia was diagnosed in 24.4% of the patients. Females present a two-fold increased risk of developing anemia (OR 2.11, 95% CI 1.48-3.01, p < 0.001). Patients subjected to gastric sleeve and gastric band surgery present approximately half the risk of anemia when compared with gastric bypass surgery (RYGB) (OR 0.46, 95% CI 0.35-0.59, p < 0.001; OR 0.51, 95% CI 0.36-0.72, p < 0.001). None of the other variables evaluated showed association with the outcome.

CONCLUSION

In our study, the only factors associated with an increased risk of developing anemia were female gender and RYBG surgery. Prospective studies evaluating the risk factors for anemia in patients undergoing bariatric surgery are needed.