Oh Yun Jung, Kim Myounghee, Lee Hajeong, Lee Jung Pyo, Kim Ho, Kim Sejoong, Oh Kook-Hwan, Joo Kwon Wook, Lim Chun Soo, Kim Suhnggwon, Kim Yon Su, Kim Dong Ki
Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
Nephrol Dial Transplant. 2012 Jun;27(6):2396-403. doi: 10.1093/ndt/gfr763. Epub 2012 Jan 18.
Vitamin D deficiency is known as an important risk factor for mortality in patients with chronic kidney disease (CKD). Nevertheless, the association of renal function itself with vitamin D status or serum 25-hydroxyvitamin D (25OHD) level has not been investigated thoroughly.
We examined the association between the estimated glomerular filtration rate (eGFR) and serum 25OHD levels using data from the 4th Korean National Health and Nutritional Examination Survey 2008. Generalized additive models (GAMs) were used to examine the relationship between eGFR and serum 25OHD levels and to estimate a threshold value of eGFR that predicts changes in serum 25OHD levels.
The mean serum 25OHD level was 20.4 ± 9.1 ng/mL, and the overall prevalence of vitamin D deficiency was 29.9% in this population. The prevalence of vitamin D deficiency began to increase at eGFR levels <45 mL/min/1.73 m(2). After adjustment, the logistic regression of dichotomized eGFR levels with a cut-point of 45 mL/min/1.73 m(2) yielded an increased odds ratio for vitamin D deficiency. Additionally, the continuous relationship between eGFR and 25OHD levels was explored using GAMs adjusted for various confounding factors. In this analysis, the difference from the mean serum 25OHD started to increase below an eGFR threshold of 55.4 mL/min/1.73 m(2), which suggests that renal function is directly related to the serum 25OHD levels in patients with CKD Stages 3-5.
Although moderate renal dysfunction (eGFR < 45 mL/min/1.73 m(2)) is an important predictor of vitamin D deficiency, serum 25OHD levels start to decrease below an eGFR level of ~60 mL/min/1.73 m(2) independent of other risk factors. These results suggest that more careful attention to 25OHD levels may be needed when patients reach Stage 3 CKD.
维生素D缺乏是慢性肾脏病（CKD）患者死亡的重要危险因素。然而，肾功能本身与维生素D状态或血清25-羟基维生素D（25OHD）水平之间的关联尚未得到充分研究。
我们使用2008年第四次韩国国民健康与营养检查调查的数据，研究了估算肾小球滤过率（eGFR）与血清25OHD水平之间的关联。采用广义相加模型（GAMs）来研究eGFR与血清25OHD水平之间的关系，并估计能够预测血清25OHD水平变化的eGFR阈值。
该人群的血清25OHD平均水平为20.4±9.1 ng/mL，维生素D缺乏的总体患病率为29.9%。当eGFR水平<45 mL/min/1.73 m²时，维生素D缺乏的患病率开始上升。调整后，以45 mL/min/1.73 m²为切点对eGFR水平进行二分的逻辑回归显示，维生素D缺乏的比值比增加。此外，使用针对各种混杂因素进行调整的GAMs探索了eGFR与25OHD水平之间的连续关系。在该分析中，血清25OHD均值的差异在eGFR阈值低于55.4 mL/min/1.73 m²时开始增大，这表明在CKD 3-5期患者中，肾功能与血清25OHD水平直接相关。
尽管中度肾功能不全（eGFR<45 mL/min/1.73 m²）是维生素D缺乏的重要预测因素，但血清25OHD水平在eGFR约60 mL/min/1.73 m²以下时开始下降，且独立于其他危险因素。这些结果表明，当患者达到CKD 3期时，可能需要更密切关注25OHD水平。
