Reappraisal in two European cohorts of the prognostic power of left ventricular mass index in chronic kidney failure

Left ventricular hypertrophy is a strong causal risk factor of cardiovascular morbidity and death in end stage kidney failure, and its prognostic value is taken for granted in this population. However, the issue has never been formally tested by state-of-art prognostic analyses. Therefore, we determined the prognostic power of the left ventricular mass index (LVMI) for all-cause and cardiovascular death beyond and above that provided by well validated clinical risk scores, the annualized rate of occurrence cohort risk scores (ARO, all cause death risk and cardiovascular risk). Two large cohorts that measured LVMI in 207 hemodialysis patients in the South Italian CREED cohort and 287 patients in the French Hospital Manhes cohort were analyzed. Over a two year follow-up, 123 patients died (cardiovascular death 65%). In Cox models both the LVMI and the ARO risk scores were significantly related to all-cause and cardiovascular death. In prognostic analyses, LVMI per se showed an inferior discriminatory power (Harrell's C index) to that of the ARO risk scores (all-cause death: -10%; cardiovascular death: -5%). LVMI largely failed to improve model calibration based on the ARO risk scores, and added nonsignificant discriminatory power (Integrated Discrimination Index +2% and +3%) and quite limited reclassification ability (Net Reclassification Index +4.3%, and +8.8) to the ARO risk scores. Thus, while left ventricular hypertrophy remains a fundamental treatment target in end stage kidney failure, the measurement of LVMI solely for risk stratification is unwarranted in this condition.