Differential Signature of Obesity in the Relationship with Acute Kidney Injury and Mortality after Coronary Artery Bypass Grafting

The Impact of Obesity on Kidney Disease: Observational Cohort Study Analyzing 14,492 Kidney Biopsy Cases

BACKGROUND

The obesity epidemic is associated with the emergence of new kidney diseases including obesity-related glomerulopathy (ORG) and metabolic syndrome-associated disorders. However, the effects of obesity on prevalence and outcome of biopsy-proven kidney disease are not well known.

METHODS

We analyzed 14,492 kidney biopsies in 18 hospitals from 1979 to 2018 in Korea. Obesity was defined as a body mass index value of ≥ 30 kg/m².

RESULTS

The most common disease was IgA nephropathy (IgAN) in both obese and non-obese participants (33.7% vs. 38.9%). Obesity was associated with a higher risk of focal segmental glomerulosclerosis (FSGS) and hypertensive nephropathy (HT-N) (odds ratio [OR], 1.72, 95% confidence interval [CI], 1.37-2.17; OR, 1.96, 95% CI, 1.21-3.19) and a lower risk of IgAN (OR, 0.74, 95% CI, 0.62-0.88). During the median follow up of 93.1 ± 88.7 months, obesity increased the risk of end-stage kidney disease (ESKD) in patients with IgAN (relative risk [RR], 1.49, 95% CI, 1.01-2.20) and lupus nephritis (LN) (RR, 3.43, 95% CI, 1.36-8.67). Of 947 obese individuals, ORG was detected in 298 (31.5%), and 230 participants had other kidney diseases, most commonly, IgAN (40.9%) followed by diabetic nephropathy (15.2%). Participants with ORG, when combined with other renal diseases, showed higher risks for developing ESKD compared to those with ORG alone (RR, 2.48, 95% CI, 1.09-5.64).

CONCLUSION

Obesity is associated with an increased risk of FSGS and HT-N, and also increase the ESKD risk in IgAN and LN patients. ORG in obese participants may have favorable renal outcomes if it occurs alone without any other renal disease.

Obese elderly patients with hip fractures may have better survival outcomes after surgery

BACKGROUND

In recent years, there has been an increasing amount of research on the "obesity paradox". So our primary objective was to explore whether this phenomenon exists in our study, and secondary objective was to determine the effect of body mass index (BMI) on major complications, and the incidence of acute kidney injury (AKI) after hip fracture surgery after controlling for confounding factors.

METHODS

We included patients over 70 years old with hip fracture who were admitted to the Department of Orthopedics, Peking University First Hospital between 2015 and 2021. Patients were classified as underweight (UW, < 18.5 kg/m²), normal weight (NW, 18.5-24.9 kg/m²), overweight (OW, 25.0-29.9 kg/m²) and obese (OB, ≥ 30.0 kg/m²). We analyzed demographic characteristics, operation information and postoperative outcomes. Using multivariate regression with normal-weight patients as the reference, we determined the odds of 1-year mortality, major complications, and AKI by BMI category.

RESULTS

A total of 644 patients were included. Nine percent of patients died after 1 year, 18% had major postoperative complications, and 12% had AKI. There was a U-shaped relationship between BMI and the rates of major complications or AKI. However, there was a linear decreasing relationship between 1-year mortality and BMI. After controlling for confounding factors, multivariate regression analysis showed that the risk of 1-year mortality after surgery was 2.24 times higher in underweight patients than in normal-weight patients (P < 0.05, OR: 2.24, 95% CI 1.14-4.42). Compared with normal-weight patients, underweight patients had a 2.07 times increased risk of major complications (P < 0.05, OR 2.07, 95% CI 1.21-3.55), and the risk of major complications in obese patients was 2.57 times higher than that in normal-weight patients (P < 0.05, OR 2.57, 95% CI 1.09-6.09). Compared with normal-weight, underweight patients had a 2.18 times increased risk of AKI (P < 0.05, OR 2.18, 95% CI 1.17-4.05).

CONCLUSIONS

The 1-year mortality risk of patients with higher BMI was significantly reduced. Besides, compared with normal-weight patients, underweight patients and obese patients have a higher risk of major complications; low-weight and obese patients are at higher risk for AKI.

Association of Body Mass Index and Acute Kidney Injury Incidence and Outcome: A Systematic Review and Meta-Analysis

This study aims to provide pooled estimates for the incidence of acute kidney injury (AKI) in overweight, obese, and normal body mass index (BMI) patients, and to assess impact of BMI on mortality and chronic kidney disease (CKD) rates. We conducted literature search using online databases to analyze outcomes of BMI. This meta-analysis included 22 studies. Compared to normal BMI, underweight, overweight, or obese patients had higher risk of having AKI. Underweight individuals had 17% lower CKD risk (relative risk [RR]: 0.83, 95% confidence interval [CI]: 0.75, 0.90) while patients that were overweight (RR: 1.15, 95% CI: 1.08, 1.22) and obese (RR: 1.21, 95% CI: 1.10, 1.33) had higher risk of having CKD. Lower than normal BMI was associated with higher mortality risk (RR: 1.58, 95% CI: 1.35, 1.85), while being overweight or obese correlated with the decreased risk of mortality. An increased risk of AKI combined with an increased risk of mortality calls for renal protective strategies in subjects who are underweight at the time of hospital admission.

Short-term Mortality and Postoperative Complications of Abdominal Aortic Aneurysm Repair in Obese versus Non-obese Patients

Background

Obesity is a risk factor not only for abdominal aortic aneurysm (AAA) but also for complications after vascular surgery. This study was to determine the effect of obesity on short-term mortality and post-intervention complications after AAA repair.

Methods

A systematic review and meta-analysis were performed. A systematic search was performed in PubMed; the articles describing the differences in post-intervention complications after open or endovascular repair of an AAA between obese and non-obese patients were selected. The primary outcome was short-term mortality defined as in-hospital mortality or mortality within 30 days after AAA repair. The secondary outcomes were cardiac complications, pulmonary failure, renal failure, and wound infections. The meta-analysis was performed using OpenMeta.

Results

Four articles were included in the meta-analysis; these articles included 35,989 patients of which 10,917 (30.3%) were obese. The meta-analysis showed no significant differences for short-term mortality (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.69-1.04). Also, no significant difference was found in pulmonary failure (OR, 1.09; 95% CI, 0.85-1.42). However, obese patients were less likely to suffer from cardiac complications (OR, 0.73; 95% CI, 0.55-0.96). Nevertheless, there was a significantly higher risk of renal failure (OR, 1.16; 95% CI, 1.05-1.30) and wound infections (OR, 1.92; 95% CI, 1.55-2.38) in obese patients.

Conclusion

Obesity is not a risk factor for short-term mortality after AAA repair compared to non-obesity. Moreover, obese patients suffer less from cardiac complications than non-obese patients.

Postoperative complications associated with coronary artery bypass graft surgery and their therapeutic interventions

Coronary artery disease is one of the commonest surgery demanding cardiovascular diseases. Coronary artery bypass graft surgery is practiced all over the world for the treatment of coronary artery disease. Systemic trauma during the surgery is associated with a wide range of complications, some of which are fatal. Preoperative risk factors such as age, previous illness and obesity are common predictors of these adverse events. Advances in therapeutic medicine have allowed timely treatment of these adverse events and co-morbidities. This review summarizes some of the most occurring complications associated with coronary artery bypass graft and corresponding treatment options.