To systematically evaluate the clinical efficacy and prognosis of plasma exchange combined with hormones and/or immunosuppressive agents in treating severe renal impairment of ANCA-associated vasculitis.

Computer search was made in MEDLINE via OvidSP, Embase, China Biomedical Literature Database, China National Knowledge Internet, Wanfang Data and CQVIP Database. The search period was from the establishment of the database to April 2019. Related literatures were collected from randomized controlled trials (RCT) and cohort studies on treatment of severe renal impairment in ANCA-associated vasculitis with plasma exchange combined with hormones and/or immunosuppressive agents. A total of 939 patients were included, including 503 patients in the standard treatment group (corticosteroids alone or combining immunosuppressive agents) and 436 patients in the combination treatment group (standard treatment combined with plasma exchange). Meta-analysis was performed with the software of Review Manager 5.3 version.

Regarding the improvement of renal function: the blood creatinine decreased more in the combination treatment group (SMD=-0.51, 95%CI: -0.92 to -0.09, P=0.02). Subgroup analysis results showed that the short-term and long-term efficacy of the combination treatment group improved with statistically significant difference compared with the standard treatment group. There was no significant decrease in urea nitrogen in the combination treatment group (SMD=-0.25, 95%CI: -0.37 to 0.87, P=0.43). In terms of primary disease control: Birmingham vasculitis activity score (BVAS) of the combination treatment group decreased more significantly (MD=-1.51, 95%CI: -2.38 to -0.64, P<0.05); The decrease of ANCA level in combination treatment group was more obvious (MD=-27.68, 95%CI: -42.17 to -13.19, P<0.05). In terms of long-term follow-up outcomes: the risk of death or end-stage renal disease in the combination treatment group was less than that in the standard treatment group (RR= 0.67, 95%CI: 0.53-0.84, P<0.05); The frequency of freedom from dialysis in the combination treatment group was higher than that in the standard treatment group (RR=1.32, 95%CI: 1.08-1.61, P<0.05). The incidence of adverse reactions in the combination treatment group was similar to that in the standard treatment group, and the adverse reactions mainly included pulmonary infection, tuberculosis, herpes zoster, gastrointestinal symptoms, and liver damage (OR=0.64, 95%CI: 0.39-1.05, P=0.08).

Plasma exchange combined with hormones and/or immunosuppressive agents could effectively reduce serum creatinine level, serum ANCA level, BVAS, and the composite end point and all-cause mortality of end-stage renal disease, so as to improve disease control rate, while the incidence of adverse reactions was similar between the two groups during the follow-up.