Objectives We sought to systematically review the epidemiology of biopsy-proven lupus nephritis (BPLN) by conducting a meta-analysis of articles associated with BPLN.
Methods We systematically searched the PubMed database from January 1982 to June 2013. Studies were selected using predefined eligibility criteria, and data were extracted independently by 2 of the authors, which then were calculated by STATA 12.0 meta-analysis program.
Results 19 studies that met our criteria for inclusion were elected into the analysis. The mean age of lupus patients was about 30 years at renal biopsy. The proportion of female among patients with BPLN was 86%. BPLN developed in 29% of lupus patients and accounted for 60% of secondary glomerular diseases (SGD) in renal biopsy databases. The prevalence rate of BPLN among lupus patients in Asian Saudi Arabia was significantly higher than the pooled data in European and American countries (43% vs. 26%, p<0.05). Similarly, the pooled rate of BPLN among SGD in renal biopsy databases in Asian and Latin American countries was also significantly higher than that in European Poland (63% vs. 34%, p<0.05). The overall survival rates of BPLN patients were 94%, 86%, 71% at 5, 10, 20 years, respectively. However, before 1995, they were only 84%, 72%, 52%, respectively, significantly lower than those (96%, 89%, 80%) after 1995 (p all <0.05). Class IV nephritis, present in 40% of BPLN patients, was identified as a high risk factor for renal failure that contributed to patients' poor prognosis.
Conclusions LN is a common complication of young female lupus patients and is the most prevalent etiology of SGD in renal biopsy databases despite its different prevalence rates in distinct regions. Although the prognosis of BPLN has been greatly improved in the past years, the long-term survival is still unsatisfactory and more attention should be paid for Class IV nephritis due to its high frequecy and extreme risk to induce poor prognosis.
Disclosure of Interest None declared