Abstract 13275: The Intermountain Risk Score is a Robust Predictor of Mortality in Patients With Chronic Kidney Disease
Introduction: Chronic kidney disease (CKD) is a common disorder associated with increased cardiovascular mortality. The Intermountain Risk Score (IMRS) is an electronic risk calculator that utilizes the complete blood count (CBC), basic metabolic panel (BMP), age and sex to predict all-cause mortality. We tested whether IMRS predicts mortality in CKD patients (pts) and is additive to CKD staging. We also tested whether serum phosphate (PO4) or urinary albumin (U-alb)/creatinine (Cr) ratio adds predictive value.
Methods: From October 2005 to May 2013, pts with CKD classes IIIa-V seen in the Intermountain Healthcare system with concurrent BMP and CBC tests were followed for survival at 1y (N=3,872) and 5y (N=3,727). Survival analyses were performed for pre-defined IMRS low-, medium- and high-risk groups for combined and separate CKD stages, and for PO4 and U-alb/Cr. Receiver operator characteristic curves were used to generate c-statistics.
Results: For pts across the spectrum of CKD, mortality was significantly increased with medium- and high-risk compared to low-risk IMRS categories (1y medium-risk hazard ratio [HR]=4.60 [95% CI: 2.97, 7.12], 1y high-risk: HR=17.6, [11.46, 27.14]; and 5y medium-risk HR=2.5 [1.9, 3.2], 5y high-risk: HR=6.87 [5.44, 8.68], P < 0.001 for all). When adjusted for CKD stage, IMRS remained predictive (1y: HR=3.85 [2.47, 5.99] for medium-risk, HR=12.66 [8.11, 19.76] for high-risk; and 5y: HR=2.30 [1.80, 2.95] for medium-risk, HR=5.55 [4.36, 7.06] for high-risk, P < 0.001 for all). IMRS predicted 1y mortality more efficiently (c=0.735 [se 0.013]) than CKD stage (c=0.660 [se 0.013]); while combining IMRS and CKD stage increased the c-statistic to c=0.759 (se 0.014). PO4 predicted mortality (HR=1.23 [1.15-1.31]) but added only slightly to the IMRS 1y predictive ability (c=0.741 [se 0.016]). U-alb/Cr was not independently associated with mortality (HR=1.01 [0.99-1.01]).
Conclusion: IMRS is a strong predictor of mortality in patients with CKD and is robustly complementary to CKD stage in refining risk stratification. Given the universal electronic availability and low cost of CBC and BMP, IMRS may represent a major advance in CKD risk assessment and management.
Author Disclosures: A.C. Rassa: None. B.D. Horne: None. R. McCubrey: None. T.L. Bair: None. J.B. Muhlestein: None. D. Morris: None. J.L. Anderson: None.
- © 2014 by American Heart Association, Inc.