Lower blood vitamin D levels are associated with an increased incidence of contrast-induced nephropathy in patients undergoing coronary angiography.

Background: Vitamin D deficiency may be associated with an increased risk of renovascular disease. We assessed the correlation between vitamin D levels and contrast-induced nephropathy (CIN) in patients undergoing coronary angiography (CAG).

Methods: Vitamin D and parathyroid hormone (PTH) levels were assessed before CAG in 403 patients. Estimated glomerular filtration rate (eGFR) was calculated using the Cockcroft-Gault equation. Patients with eGFR < 60 mL/min/1.73 m(2) were hydrated with 0.9%-saline at 1 mL/kg/h for 12 hours before and after CAG. CIN was defined as serum creatinine increase of > 0.5 mg/dL or > 25% within 48-72 hours after CAG.

Results: CIN developed in 74 participants. Baseline eGFR, blood urea and creatinine in CIN (+) and (-) groups were not significantly different (P = 0.14, P = 0.07, and P = 0.61, respectively). Total volume of contrast medium (CM) was higher in the CIN (+) group (132 ± 64 mL vs 90 ± 41 mL; P = 0.01). Vitamin D levels were lower (median 8.5 [range, 0.5-26.6] ng/mL vs 14.9 [range, 1.9-93.5] ng/mL; P = 0.01) and PTH levels were higher (median 73.9 [range, 22-530] pg/mL vs 44.2 [range, 5-361] pg/mL; P = 0.01) in the CIN (+) group. Multivariate logistic regression analysis revealed that lower vitamin D levels (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.11-1.26; P = 0.01) and increased CM volume (OR, 1.01; 95% CI, 1.008-1.017; P = 0.01) were independently correlated with CIN. In patients who had undergone percutaneous coronary intervention, lower levels of vitamin D were independently associated with CIN development.

Conclusions: Lower vitamin D levels, implying possible vitamin D deficiency, are associated with a higher incidence of CIN.