Predicting Mortality in Microscopic Polyangiitis with Renal Involvement: A Survival Analysis Based on 64 Patients

Abstract

Background: To determine predictors of survival in patients with microscopic polyangiitis (MPA). Methods: A cohort of 64 patients who met the Chapel Hill criteria for MPA with renal involvement participated in the study. All subjects received cytotoxic drugs. All of the diagnoses were biopsy proven. Results: We retrospectively studied 64 patients (median age, 59 years; male/female ratio, 1.6:1). The mean follow-up was 38 months; 34 (53.13%) patients died or acquired end-stage renal disease. According to univariate analysis, a preliminary prognostic value was attributed to serum creatinine (Scr) > 459 μmol/L (p < 0.001); erythrocyte sedimentation rate (ESR) > 99 mm/h (p < 0.001); serum albumin < 30 g/L (p < 0.001); and hemoglobin < 84 g/L (p < 0.001). Logistic regression analysis showed that Scr level (β = 1.02, p = 0.0002) and ESR (β = 1.02, p = 0.0002) at baseline were associated with poor prognosis, and Cox regression analysis further confirmed this result [Scr: β = 1.004, 95% confidence interval (CI): 1.002–1.006, p < 0.001; ESR: β = 1.018, 95% CI: 1.000–1.037, p = 0.046]. The receiver operating characteristic curve showed that Scr and ESR were predictors of MPA patient prognosis, their areas under the curves were 0.95 and 0.80, their sensitivities were 94.1% and 92.3%, and their specificities were 94% and 70%, respectively. Conclusion: Despite the small number of patients in this study, the prevalence of renal vasculitis was high in patients with MPA. The level of Scr and ESR may be a useful clinical biomarker for monitoring prognosis.

• microscopic polyangiitis
• ANCA
• renal vasculitis
• outcome
• survival analysis

ACKNOWLEDGMENTS

We thank all of the nephrologists in the Renal Division, Renji Hospital, Shanghai Jiao Tong University School of Medicine, for their work.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

This work was supported by the National Basic Research Program of China 973 Program No. 2012CB517600 (Grant No. 2012CB517602); the National Key Technology Research and Development (R&D) Program of the Ministry of Science and Technology of China (Grant No. 2011BAI10B04); the National Natural Science Foundation of China (Grant No. 81102700); the Science and Technology Commission of Shanghai Municipality (Grant Nos. 09dZ1973600 and 10JC1410100); and the Shanghai Municipal Health Bureau (Grant No. 2010L063A).