Obesity is a growing problem both in the United States and around the world. Defined as excessive fat accumulation that presents a risk to health, obesity has been found to be a major risk factor in several chronic diseases. Objectively, overweight is defined as a body mass index (BMI in kg/m2) greater than 25, and obesity is defined as a BMI greater than 30. Since 1975 the rate of obesity has nearly tripled, leading the World Health Organization (WHO) to declare obesity a global epidemic and worldwide public health crisis in the 1990s.
According to the WHO, there were 1.9 billion overweight and 650 million obese adults worldwide in 2016, making the overall prevalence of overweight adults 39% and obese adults 13%. The pediatric population has not been left unaffected by this epidemic. In 2016 over 340 million children and adolescents age 5–19 were overweight or obese, a prevalence of 18% compared to 4% in 1975. While the cause of obesity is largely thought to be multifactorial, at its foundation is an imbalance between calories consumed and calories expended.1
The demographics among patients awaiting renal transplant has mimicked the national trend: of patients registered for a renal transplant between 1995 and 2006, the proportion of patients categorized as overweight (BMI 25–30) was 34.3%, obese (BMI 30–35) was 19.3%, and severely or morbidly obese (BMI >35) was 9.9%.2
OBESITY LEADS TO RENAL FAILURE
Obesity is a well-known risk factor for multiple medical problems. Obesity can lead to chronic diseases such as diabetes and hypertension, which in turn can cause proteinuria, nephrotic syndrome, and chronic kidney disease (CKD).3 Even in the absence of related comorbid conditions, obesity has been found to be independently associated with the development of CKD.4 Based on a 15- to 35-year cohort of over 300,000 members of Kaiser Permanente of Northern California aged 18 or older, the increase in the rate of end-stage renal disease (ESRD) was proportional to the increase in BMI independent of hypertension or diabetes.5
Obesity leads to an increased metabolic demand, placing greater stress on the kidneys.6 Obesity-related glomerulopathy is characterized by hyperfiltration and glomerulomegaly with or without focal and segmental glomerulosclerosis. It often presents as slowly increasing subnephrotic proteinuria.7 While weight loss can slow the progression of CKD, it has a paradoxical effect once patients progress to ESRD requiring dialysis. Those patients undergoing dialysis with higher BMIs were found to have a lower mortality rate than those with a lower BMI.8
THE IMPACT OF OBESITY IN TRANSPLANT DONORS
With an ever-growing waiting list for organs, the criteria for donation has a major impact on the number of organs available for transplant. The increase in obesity in the general population has also led to an increase in obesity ...