Prevalence and outcomes in people with obesity across the spectrum of chronic kidney disease

Abstract

Background: Obesity and chronic kidney disease (CKD) are conditions with increasing prevalence. The interplay between these two chronic illnesses has an impact on long term outcomes in people who have both. Methods: Simple descriptive statistics and longitudinal mixed modelling were used to evaluate the prevalence of obesity in dialysis patients in Australia and New Zealand. A systematic review was conducted to assess the relationship of obesity with mortality in the spectrum of CKD. Cox proportional hazards models were used to assess the relationship of obesity and outcomes in elderly women with mild to moderate CKD, paediatric kidney transplant recipients and dialysis patients who were eligible for transplant via the deceased donor waiting list. Results: I found the prevalence of obesity in dialysis populations are increasing. In the existing literature, I found being obese may be protective for all-cause mortality in pre-dialysis and haemodialysis populations, but not in peritoneal dialysis or transplant recipients. The most pronounced risk of mortality occurs at the extreme categories of BMI. In elderly women, being underweight or having low fat mass was predictive of increased mortality however CKD did not modify this relationship. In paediatric transplant recipients, obesity was a significant risk factor for graft loss in children. Lastly, I found a substantial reduction in access to the deceased donor waitlist for dialysis patients with obesity and an apparent sex inequity such that obese women were being further disadvantaged. Conclusion: Obesity is an on-going challenge for nephrology. Although extremes of BMI are the most at risk, further investigation into other measures of adiposity need to be explored. Further exploration into wait-listing practices also needs to be explored to identify barriers to people with obesity being listed for deceased donor transplantation.