# U- and inverted U-shaped link between weight-adjusted waist index and chronic kidney disease in hyperuricemic adults

## TL;DR

This study finds a U- and inverted U-shaped relationship between a body fat measure and chronic kidney disease in adults with high uric acid levels.

## Contribution

The study reveals a novel composite relationship between weight-adjusted waist index and CKD in hyperuricemic individuals.

## Key findings

- The highest WWI quartile had a 60% higher CKD prevalence compared to the lowest quartile.
- The WWI-CKD relationship showed a U-shape below 11.36 cm/√kg and an inverted U-shape above this threshold.
- An optimal WWI range may be associated with lower CKD prevalence in hyperuricemic adults.

## Abstract

Hyperuricemia is closely associated with an increased risk of chronic kidney disease (CKD) and is frequently accompanied by abnormal fat distribution. However, the relationship between fat distribution and CKD prevalence in hyperuricemic populations remains unclear. This study investigates the association between the weight-adjusted waist index (WWI) and CKD among adults with hyperuricemia, using data from the National Health and Nutrition Examination Survey (NHANES).

Data from 5,330 hyperuricemic adults (2007–2018 NHANES) were analyzed. WWI was calculated by dividing waist circumference by the square root of body weight. CKD was defined by an estimated glomerular filtration rate (eGFR) falling below 60 mL/min/1.73 m² or by albuminuria levels greater than 30 mg/g. To evaluate the linkage between WWI and CKD, weighted multivariate logistic regression models and restricted cubic spline (RCS) analyses were utilized.

Individuals within the highest WWI quartile faced a 60% greater prevalence of CKD compared to the lowest quartile (OR = 1.60, 95% CI = 1.01–2.53, p = 0.047). RCS analysis revealed a composite pattern. The curve demonstrates a U-shape when WWI is below 11.36 cm/√kg, shifting to an inverted U-shape as WWI exceeds 11.36 cm/√kg.

A significant association was observed between WWI and CKD prevalence in hyperuricemic adults, characterized by a composite U-shaped and inverted U-shaped relationship. This indicates the potential existence of an optimal WWI range associated with a lower prevalence of CKD. Further studies are required to confirm these observations.

The online version contains supplementary material available at 10.1186/s12889-025-26076-8.