Evaluation of crescent formation as a predictive marker in immunoglobulin A nephropathy: a systematic review and meta-analysis

// Xue Shao 1, 2, 3 , Bingjue Li 1, 2, 3 , Luxi Cao 1, 2, 3 , Ludan Liang 1, 2, 3 , Jingjuan Yang 1, 2, 3 , Yucheng Wang 1, 2, 3 , Shi Feng 1, 2, 3 , Cuili Wang 1, 2, 3 , Chunhua Weng 1, 2, 3 , Xiujin Shen 1, 2, 3 , Hong Jiang 1, 2, 3 and Jianghua Chen 1, 2, 3 1 Kidney Disease Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China 2 Kidney Disease Immunology Laboratory, The Third Grade Laboratory, State Administration of Traditional Chinese Medicine of China, Hangzhou, China 3 Key Laboratory of Multiple Organ Transplantation, Ministry of Health, Key Laboratory of Nephropathy, Hangzhou, China Correspondence to: Jianghua Chen, email: chenjianghua@zju.edu.cn Hong Jiang, email: annie.jh@163.com Keywords: Immunoglobulin A (IgA) nephropathy, Oxford classification, crescent lesions, meta-analysis Received: September 26, 2016     Accepted: April 07, 2017     Published: April 28, 2017 ABSTRACT The 2009 Oxford Classification of immunoglobulin A (IgA) nephropathy (IgAN) identifies four histological features as predictors of renal prognosis: mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), and tubular atrophy/interstitial fibrosis (T). However, the clinical and prognostic significance of crescent formation still remains controversial. Therefore, we performed a meta-analysis to evaluate the association between crescents and kidney outcome in IgAN. A total of 20 studies published from January 2009 to July 2016 involving 5,285 patients were included after systematic searches of PubMed and EMBASE databases. Pooled results showed that crescent lesions were associated with kidney failure (HR, 1.93; 95% CI, 1.49-2.50; P < 0.001). IgAN patients with crescents had lower eGFR levels (SMD, -0.21; 95% CI, -0.40--0.03; P = 0.023); higher proteinuria levels (SMD, 0.87; 95% CI, 0.11-1.63; P = 0.024); a larger number of patients with M1 (RR, 1.22; 95% CI, 1.07-1.40; P = 0.003), E1 (RR, 4.83; 95% CI, 3.04-7.66; P < 0.001), S1 (RR, 1.76; 95% CI, 1.11-2.80; P = 0.016) and T1/2 (RR, 2.74; 95% CI, 2.10-3.57; P < 0.001) lesions; and received immunosuppressive therapy more frequently (RD, 0.17; 95% CI, 0.11-0.23; P < 0.001). Our results suggest that crescent formation represents an efficient prognostic factor associated with progression to kidney failure and thus could be considered into the new Oxford Classification.