BMI Variability Can Predict Negative Outcomes in Chronic Kidney Disease

This article was originally published on EndocrinologyNetwork.com.

Dong Ki Kim, MD, PhD

New research suggests weight fluctuations could help predict the risk of adverse outcomes among patients with chronic kidney disease (CKD).

An analysis of more than 80,000 predialysis patients with CKD from a South Korean national health database, results suggest greater body mass index (BMI) variability was linked to a 66% greater risk of mortality, 20% greater risk of needing kidney replacement therapy, and a 19% greater risk of having a heart attack or stroke compared to those with the lowest levels of BMI variability.

“This study showed that people who had kidney function impairment with recent fluctuating body mass index had a higher risk of cardiovascular disease or death, regardless of their current body mass index,” said Dong Ki Kim, MD, PhD, professor in the Department of Internal Medicine at Seoul National University Hospital, in a statement. “This result suggests that people with kidney function impairment should pay attention to their fluctuating weight status, and those with fluctuating weight may benefit from receiving appropriate screening and risk factor management to prevent cardiovascular disease or progression of their kidney dysfunction.”

With the burden of obesity continuing to balloon, Kim and a team of colleagues from Seoul National University Hospital sought to describe associations between BMI variability and prognosis of patients with CKD. To do so, investigators designed the current study as a retrospective observational study using data from the national health screening database of South Korea.

An initial search of patients with data from health screenings in 2013-2014 and data from at least 3 visits prior to baseline, returned 11,651,753 individuals. After application of additional inclusion criteria, investigators identified a cohort of 84,636 patients with an eGFR below 60 mL/min/1.73m2 for inclusion in their analysis. For the purpose of analysis, investigators excluded patients with a history of myocardial infarction or stroke and those with prevalent end-stage kidney disease, which was defined as an eGFR less than 15 mL/min/1.73m2.

The study cohort had a mean age of 68 (IQR, 60-74) years, 51% were male, and the median BMI was 24.6 (IQR, 22.6-26.7) kg/m2. During a follow-up period lasting a median of 4.0 (IQR, 3.4-4.5) years, 4782 patients died, 3276 required maintenance kidney replacement therapy, 1839 experienced myocardial infarction, and 2666 experienced a stroke event.

After stratification into quartiles based on levels of BMI variability, investigators found those with the greatest levels of variability had significantly greater risks of all-cause mortality (HR, 1.662 [95% CI, 1.530-1.806]; P <.001), kidney replacement therapy (HR, 1.201 [95% CI, 1.087-1.327]; P <.001), myocardial infarction (HR, 1.191 [95% CI, 1.046-1.356]; P=.003), and stroke (HR, 1.189 [95% CI, 1.067-1.325]; P=.01) when compared to their counterparts with the lowest levels of variability. Investigators pointed out similar results were observed when dividing subgroups according to positive or negative trends in BMI during the assessment period.

Investigators anoted variability in certain metabolic syndrome components were also significantly associated with the prognosis of this patient population, including waist circumference, fasting blood glucose, blood pressure, and lipid profile. Additionally, investigators also pointed out those with a greater number of metabolic syndrome components with high variability had a worse prognosis than their counterparts with less variability.

This study, “The Prognostic Significance of Body Mass Index and Metabolic Parameter Variabilities in Predialysis Chronic Kidney Disease: A Nationwide Observational Cohort Study,” was published in the Journal of the American Society of Nephrology.