Comparison of Renal Outcome among Japanese Patients with or without Microangiopathic Hemolysis in Malignant Phase Hypertension: A Single-Center Retrospective Study

Background/Aims: Although microangiopathic hemolysis (MAH) is a well-known complication of malignant phase hypertension (MPH), only less data on whether MAH in MPH predicts renal outcome exist. Therefore, we evaluated whether MAH was associated with the renal outcome in patients with MPH. Methods: We conducted a single-center, retrospective, cohort study. Data from 35 patients diagnosed with MPH between October 1998 and January 2015 were analyzed. MPH was defined as the presence of a diastolic blood pressure of ≥120 mm Hg and grades III/IV hypertensive retinopathyaccording to the Keith-Wagener-Barker classification. MAH was defined as the presence of a low platelet count(9/L) together with either an elevated level of lactate dehydrogenase (LDH; >220 U/L), or the presence of schistocytes, or both and the normalization of platelet and LDH level or schistocytelevels after adequate blood pressure control was achieved. The primary outcome was dialysis induction. Results: Fifteen patients had MAH. Those with MAH had significantly severe renal dysfunction at the onset of MPH. The length of follow-up (median, interquartile range) of patients with MAH and those without MAH were 30 (16-94) and 48 (25-115) months, respectively. Dialysis was induced in 9 of 15 patients with MAH and in 6 of 20 patients without MAH. Renal survival in patients with MAH was worse than that in those without, but this was not statistically significant (p = 0.08). By multivariate Cox regression analysis, MAH was not shown to contribute to dialysis induction. Conclusion: MAH did not predict renal outcome in MPH.