Obesity Weight Loss Phenotypes in CKD: Findings From the Chronic Renal Insufficiency Cohort Study

Abstract

Introduction: Although people with chronic kidney disease (CKD) and obesity have important motivations to lose weight, weight loss is also associated with health risks. We examined whether patterns of change in systolic blood pressure (SBP), serum albumin level, and fat-free mass (FFM) can help to differentiate between healthy and high-risk weight loss in this population.

Methods: Using data from the Chronic Renal Insufficiency Cohort Study (CRIC), we estimated a joint multivariate latent class model with 6 classes to identify distinct trajectories of body mass index (BMI), albumin, and SBP among participants with obesity (BMI ≥30 kg/m² at baseline), accounting for informative missingness from death. In a secondary analysis, we fit a 6-class model with BMI and FFM.

Results: Among 2831 participants (median baseline BMI 35.6, interquartile range [IQR] 32.4-40.0 kg/m²), median follow-up was 6.8 (IQR 4.8-12.9) years, median age was 61 (IQR 54-67) years, 53% were male, 50% were non-Hispanic Black, and 82% were trying to control or lose weight at baseline. Latent classes were associated with mortality risk (5-year cumulative incidence of mortality 6.8% and 1.5% in class 6 and 3, respectively). Class 6 had the highest mortality rate and was characterized by early, steep BMI loss, early serum albumin decline, and late SBP increase. In the secondary analysis, a class characterized by steep BMI and FFM loss was associated with the highest death risk.

Conclusions: Among adults with CKD and obesity, BMI loss with concomitant serum albumin or FFM loss was associated with a high risk of death.

Keywords: nutrition; obesity; sarcopenia; weight loss.

Graphical abstract

Figure 1

Predicted latent class trajectories and cumulative incidence of death from the 6-class model. Predicted cumulative incidence of death is for a 50-year-old, non-Hispanic White female with diabetes, BMI of 35 kg/m², SBP of 130 mm Hg, serum albumin of 4.0 g/dl, and eGFR of 60 ml/min per 1.73 m² at baseline and without dialysis initiation or transplant during the follow-up period.

Figure 2

Baseline lean body mass, anthropometry, dietary intake, and physical activity characteristics by latent class membership.

Figure 3

Predicted latent class trajectories and cumulative incidence of death from the 6-class model with BMI and FFM. Predicted cumulative incidence of death is for a hypothetical 50-year-old, non-Hispanic White female with diabetes, BMI of 35 kg/m², FFM of 53.1 kg, and eGFR of 60 ml/min per 1.73 m² at baseline and without dialysis initiation or transplant during the follow-up period.

Figure 4

Results of sensitivity analysis including self-reported intentional weight loss. The figure shows hazard ratios with 95% confidence intervals from a Cox model with the estimated latent classes from the 6-class model as predictors, adjusting for covariates, intention to control or lose weight, and dialysis/transplant.