The Effects of Hyperuricemia on the Prognosis of IgA Nephropathy are More Potent in Females.

Tae Ryom Oh,Eun Hui Bae,Seong Kwon Ma,Soo Wan Kim,Sung Gyun Kim,Hong Sang Choi,Young Joo Kwon,Kyung Pyo Kang,Chang Seong Kim

doi:10.3390/jcm9010176

Abstract

Hyperuricemia is a potential risk factor for immunoglobulin A nephropathy (IgAN) progression but its sex-specific effects on IgAN progression remain unclear. This study aimed to determine the effect of serum uric acid on IgAN progression and whether its effect varied according to sex. A total of 4339 patients who diagnosed with IgAN by renal biopsy were retrospectively analyzed. We assessed the association of serum uric acid on IgAN progression using Kaplan–Meier survival analyses and Cox proportional hazards models. The study’s primary end point was IgAN progression that was defined as a 50% decline in the estimated glomerular filtration rate or the initiation of dialysis. On average, the serum uric acid levels were higher in the men than in the women. In the fully adjusted Cox proportional hazards model that considered all subjects, the risk of IgAN progression increased by about 25.6% for every 1 mg/dL increase in the baseline uric acid level. The serum uric acid level was an independent risk factor for IgAN progression in both sexes but its effect was more pronounced in the women (hazard ratio [HR], 1.383; confidence interval [CI],1.263 to 1.514; p < 0.001) than in the men (HR, 1.181; CI, 1.097 to 1.272; p < 0.001) (pinteraction < 0.001). A sensitivity analysis involving serum uric acid quartiles generated consistent and robust results. In conclusion, the serum uric acid level was an independent risk factor for IgAN progression and its effect was more pronounced among the women compared with that among the men.

Highlights

In Korea, the prevalence and incidence of end-stage renal disease (ESRD) are increasing, and chronic glomerulonephritis (GN) accounts for approximately 8% of new ESRD diagnoses [1]
Compared with the control group, the hyperuricemia group had a higher prevalence of diabetes mellitus (DM), a higher urine protein-to-creatinine ratio (UPCR), and a lower estimated glomerular filtration rate (eGFR)
The results showed sex-specific difference when the men (HR, 1.188; 95% confidence intervals (CIs), 1.104 to 1.279; p < 0.001) and women (HR, 1.381; 95% CI, 1.259 to 1.513; p < 0.001) were analyzed separately

Summary

Introduction

In Korea, the prevalence and incidence of end-stage renal disease (ESRD) are increasing, and chronic glomerulonephritis (GN) accounts for approximately 8% of new ESRD diagnoses [1]. The progression of GN to chronic kidney disease (CKD) or ESRD is not uncommon and it generates a considerable socioeconomic burden [2]. Identifying modifiable risk factors associated with IgAN progression is important, because the 30-year renal survival rate for IgAN is poor at 50.3% [4]. The traditional risk factors associated with IgAN progression include elevated serum creatinine levels, hypertension, and proteinuria at diagnosis [5]. Smoking [6], hyperuricemia [7], hyperlipidemia [7], and genetic factors [8,9] are associated with IgAN progression

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