Abstract:

Objective

To investigate the relationship of 25-hydroxyvitamin D3 and the ratio of serum iron to C-reactive protein with renal function impairment in the elderly.

Methods

A cross-sectional study design was conducted，and 6512 people who underwent health examinations from 2017 to 2022 in our hospital were enrolled. Based on their glomerular filtration rate，the subjects were divided into the normal renal group and the abnormal renal function group （GFR ＜60 ml/min/1.73 m²）. Restricted cubic splines and multivariate logistic model were used to analyze the relationship of 25-hydroxyvitamin D3 and the ratio of serum iron to C-reactive protein with the renal function impairment in the elderly. The recipient operating characteristic curve and decision curve analysis methods were used to evaluate their clinical diagnostic value.

Results

The average age of the 6512 elderly people was 65.52 ±5.24 years old，and the rate of renal function impairment was 42.5%，with the male accounting for 64.3% of the total. After adjusting for age，gender，body mass index，diastolic blood pressure，total cholesterol，fasting blood glucose，homocysteine，folic acid，and other factors，the results of multivariate logistic regression analysis showed that 25-hydroxyvitamin D3 level was negatively correlated with the prevalence of renal function impairment （P ＜0.05），and so was the ratio of serum iron to C-reactive protein，with the latter being more significant in the male （P ＜0.05）. In addition，the area under the curve of 25-hydroxyvitamin D3 plus the ratio of serum iron to C-reactive protein was 0. 8295 for diagnosis of the renal function impairment.

Conclusion

25-hydroxyvitamin D3 and the ratio of serum iron to C-reactive protein were inversely correlated with the prevalence of renal function impairment in the elderly.

Key words: Serum iron to C-reactive protein ratio, 25-hydroxyvitamin D3, Renal function impairment, Correlation