Hyperuricemia Predicts an Early Decline in Renal Function among Older People: A Community-Based Cohort Study

Abstract

Whether elevated serum uric acid levels (SUA) predict renal dysfunction remains controversial in the elderly. Therefore, we investigated the association between SUA and early renal function decline defined as an estimated glomerular filtration rate (eGFR) reduction ≥30% over 2 years. From 2001 to 2010, we conducted a longitudinal cohort study comprising 44,078 participants aged ≥65 years in the Taipei City Elderly Health Examination Database. Participants were classified by 1-mg/dL increment of SUA. We used multivariable logistic and Cox regression analyses to compare the risk of early renal function decline in different SUA groups. Compared to the reference SUA group of 5.0-5.9 mg/dL, hyperuricemic participants had increased risks of eGFR decline, starting at SUA ≥6.0 mg/dL (adjusted odds ratio [aOR] = 1.21, 95% confidence interval [CI] = 1.00-1.45). The risk progressively elevated as SUA increased, with the highest in the SUA ≥10.0 mg/dL group (aOR = 3.20, CI = 2.39-4.28). Multivariable Cox regression further confirmed that hyperuricemia was 1.12-fold (CI = 1.03-1.22, SUA ≥6.0 mg/dL) to 1.6-fold (CI = 1.37-1.86, SUA ≥10.0 mg/dL) more likely to develop early eGFR decline. Hyperuricemia-associated increased risks for early eGFR decline were consistent across subgroup and sensitivity analyses. Collectively, SUA ≥6.0 mg/dL independently predicted early renal dysfunction with eGFR decline ≥30% over 2 years in older people.

Figure 1

Association between serum uric acid levels and risks of early renal function decline stratified by baseline estimated glomerular filtration rate (eGFR). Odds ratios were calculated by multivariable logistic regression after adjusting for 20 demographic and clinical variables. Serum uric acid levels of 5.0–5.9 mg/dL served as the reference group. Bars denote 95% confidence intervals.

Figure 2

Cubic spline models for the association of serum uric acid levels with the risks of early renal function decline among strata of baseline eGFR (A) >90 ml/min/1.73 m², (B) 60–90 ml/min/1.73 m², (C) 45–60 ml/min/1.73 m², and (D) <45 ml/min/1.73 m². Models were adjusted for 20 demographic and clinical variables. Filled circles denote statistical significance (p < 0.05) compared to the reference (diamond) serum uric acid level of 5.0 mg/dL. Solid line (—) denotes adjusted odds ratio and dash line (—) denotes 95% confidence intervals.

Figure 3

Subgroup analysis of the association between serum uric acid levels and risks of early renal function decline among older people. Odds ratios were calculated by multivariable logistic regression after adjustment for 20 demographic and clinical variables. Serum uric acid levels of 5.0–5.9 mg/dL served as the reference group. Bars denote 95% confidence intervals.