Mehran contrast nephropathy risk score: Is it still useful 10 years later?

BACKGROUND: Nowadays, contrast-induced nephropathy (CIN) is the third cause of acquired acute renal impairment in hospital. CIN is related to increased in-hospital morbidity, mortality, costs of medical care, and long admissions. Because of this, we hypothesized it would be useful to determine the risk of CIN with scores such as the Mehran score. The aim of this study was to validate the Mehran score in a contemporary cohort of Spanish patients with acute coronary syndrome (ACS).

METHODS: We assessed the calibration and discriminatory capacity of Mehran score to predict CIN in a cohort of 1520 patients with a definitive diagnosis of ACS and who underwent coronary angiography between March 2008 and June 2012. We excluded patients on chronic dialysis and those without data of contrast volume. The calibration of the model was assessed with the Hosmer-Lemeshow goodness-of-fit test and discriminatory capacity was assessed by C-statistic, which is equivalent to the area under the receiver-operating characteristic curve.

RESULTS: From the total group, 118 patients (7.8%) developed CIN. They were older, with higher rates of diabetes (DM) and hypertension and worse renal function and anemia (p<0.001). The odds ratios for different score components in Mehran's population versus our study were similar except for DM, hypotension, and intra-aortic balloon pump (1.6%, 2.68%, 2.55% vs 0.9%, 1.89%, and 2.86%, respectively). Calibration and discriminatory capacity of Mehran score were excellent with a Hosmer-Lemeshow p=0.7, C-statistic value >0.8.

CONCLUSIONS: Mehran risk score has been validated in our study as a good score for predicting CIN in patients with ACS who underwent coronary angiography. According to this, we support its use in patients hospitalized for ACS in order to identify the ones at risk, and to optimize CIN prophylactic therapy prior to and after catheterization.