Obesity is associated with incident chronic kidney disease in individuals with normal renal function

Abstract

Background/aims: Obesity has known to be a modifiable risk factor associated with worse outcomes in chronic kidney disease (CKD), but few studies have examined the impact of obesity on CKD incidence in the general population. The purpose of this study was to investigate the role of body mass index (BMI) and waist-to-hip ratio (WHR) as predictors of incident CKD and to evaluate the impact of weight reduction on CKD prevention.

Methods: A total of 2,711 participants from a community-based cohort with normal renal function were prospectively analyzed. Among participants with obesity, we analyzed the change in WHR to evaluate the association of obesity reduction with CKD development.

Results: During a mean follow-up of 11.03 ± 4.22 years, incident CKD occurred in 190 (7.0%) participants. In the fully adjusted multivariable Cox proportional hazard models, the risk of incident CKD increased with higher BMI (hazard ratio, 1.06; 95% confidence interval, 1.00-1.11; p = 0.033) and higher WHR (hazard ratio, 1.33; 95% confidence interval, 1.07-1.66; p = 0.009). In the Kaplan-Meier analysis, cumulative adverse renal events were significantly more common in the maintained obesity group than in the reduced obesity group (p = 0.001).

Conclusion: Both higher BMI and WHR were associated with development of CKD, but the magnitude of the effect of WHR was higher than that of BMI. Moreover, reducing obesity would be beneficial for renal prognosis.

Keywords: Body mass index; Chronic kidney disease; Obesity; Waist-to-hip ratio.

Figure 1

Study flow diagram. KoGES, Korean Genome and Epidemiology Study; eGFR, estimated glomerular filtration rate.

Figure 2

Longitudinal changes in metabolic profile parameters during the follow-up period. The X-axis denotes follow-up duration in years. BMI, body mass index; HbA1c, hemoglobin A1c; HOMA-IR, homeostasis model assessment-insulin resistance; CRP, C-reactive protein; HDL, high-density lipoprotein.

Figure 3

Log-transformed adjusted hazard ratio and 95% confidence interval for incident CKD probability associated with (A) BMI and (B) WHR. The BMI and WHR exhibited a positive correlation with the risk for incident CKD. CKD, chronic kidney disease; BMI, body mass index; WHR, waist-to-hip ratio.

Figure 4

Kaplan–Meier free-of-CKD probability curve with log-rank test between the obesity group and incident CKD. Obesity according to the (A) BMI and (B) WHR was associated with poor free-of-CKD probability. The X-axis denotes time-to events duration in days. CKD, chronic kidney disease; BMI, body mass index; WHR, waist-to-hip ratio.

Figure 5

Kaplan–Meier free-of-CKD probability curve with log-rank test according to obesity reduction. The X-axis denotes time-to events duration in days. CKD, chronic kidney disease; WHR, waist-to-hip ratio.

Figure 6

Multivariable Cox regression analysis for incident CKD according to WHR, stratified by subgroups. Models were adjusted for age, sex, HTN, DM, alcohol consumption, smoking, LDL cholesterol, hemoglobin, CRP, and baseline eGFR. HR, hazard ratio; CI, confidence interval; HTN, hypertension; DM, diabetes mellitus; CKD, chronic kidney disease; WHR, waist-to-hip ratio; LDL, low-density lipoprotein; CRP, C-reactive protein; eGFR, estimated glomerular filtration rate.