Baseline incidence and severity of renal insufficiency evaluated by estimated glomerular filtration rates in patients scheduled for contrast-enhanced CT

Background Although pre-existing renal insufficiency (RI) is the most important risk factor for contrast-induced nephropathy (CIN), the background distribution of baseline renal function has not been investigated thoroughly in patients scheduled for contrast-enhanced CT. Purpose To investigate the incidence and severity of baseline RI evaluated by estimated glomerular filtration rates (eGFR) in patients who underwent contrast-enhanced CT at an academic center. Material and Methods A total of 6586 patients (3630 men and 2956 women; mean age 57.0 ± 11.9 years) who underwent contrast-enhanced CT between January and December 2008 were retrospectively studied. Of these, 829 had cardiovascular diseases (CVD), 5116 had oncologic diseases, 178 had diabetes mellitus (DM), and 1572 had chronic liver disease (CLD). The eGFR (mL/min/1.73 m2) was calculated from their serum creatinine level. Mild, moderate-a, moderate-b, and severe RI were recorded at 60 < =eGFR < 90, 45 < =eGFR < 60, 30 < =eGFR < 45 and eGFR < 30, respectively. Results Of the 6586 patients, 1.6%, 3.7%, 13.7%, and 54.2% were judged to present with severe, moderate-b, moderate-a, and mild RI, respectively. While moderate-b-to-severe RI was recorded in 133 (3.2%) of 4161 patients aged 70 years or less, it was observed in 218 (9.0%) of the 2425 patients who were 71 years or older. Among the 829 CVD patients, 9.9% manifested moderate-b-to-severe- and 73.0% mild-to-moderate-a RI. The corresponding rates were 4.4% and 68.9% for oncologic disease, 16.9% and 61.2% for DM, and 4.8% and 71.5% for CLD patients. By univariate analysis, there was a significant association between moderate-b-to-severe RI and the advanced age, CVD, DM, and non-oncologic disease. Multivariate analysis showed that the advanced age, DM, and non-oncologic disease were statistically associated with moderate-b-to-severe RI. Conclusion The incidence of RI of eGFR < 45mL/min/1.73 m2 at baseline was high in patients with advanced age, CVD and DM and in patients without oncologic disease