Waist-to-height ratio: an accurate anthropometric index of abdominal adiposity and a predictor of high HOMA-IR values in nondialyzed chronic kidney disease patients

Abstract

Objective: Chronic kidney disease (CKD) is associated with metabolic disorders, including insulin resistance (IR), mainly when associated with obesity and characterized by high abdominal adiposity (AbAd). Anthropometric measures are recommended for assessing AbAd in clinical settings, but their accuracies need to be evaluated. The aim of this study was to evaluate the precision of different anthropometric measures of AbAd in patients with CKD. We also sought to determine the AbAd association with high homeostasis model assessment index of insulin resistance (HOMA-IR) values and the cutoff point for AbAd index to predict high HOMA-IR values.

Methods: A subset of clinically stable nondialyzed patients with CKD followed at a multidisciplinary outpatient clinic was enrolled in this cross-sectional study. The accuracy of the following anthropometric indices: waist circumference, waist-to-hip ratio, conicity index and waist-to-height ratio (WheiR) to assess AbAd, was evaluated using trunk fat, by dual x-ray absorptiometry (DXA), as a reference method. HOMA-IR was estimated to stratify patients in high and low HOMA-IR groups. The total area under the receiver-operating characteristic curves (AUC-ROC; sensitivity/specificity) was calculated: AbAd with high HOMA-IR values (95% confidence interval [CI]).

Results: We studied 134 patients (55% males; 54% overweight/obese, body mass index ≥ 25 kg/m(2), age 64.9 ± 12.5 y, estimated glomerular filtration rate 29.0 ± 12.7 mL/min). Among studied AbAd indices, WheiR was the only one to show correlation with DXA trunk fat after adjusting for confounders (P < 0.0001). Thus, WheiR was used to evaluate the association between AbAd with HOMA-IR values (r = 0.47; P < 0.0001). The cutoff point for WheiR as a predictor for high HOMA-IR values was 0.55 (AUC-ROC = 0.69 ± 0.05; 95% CI, 0.60-0.77; sensitivity/specificity, 68.9/61.9).

Conclusions: WheiR is recommended as an effective and precise anthropometric index to assess AbAd and to predict high HOMA-IR values in nondialyzed patients with CKD.

Keywords: Abdominal adiposity; Anthropometric indices; Chronic kidney disease; Insulin resistance; Receiver-operating characteristics; Waist-to-height ratio.