The risk of leukemia in patients with rheumatoid arthritis: a systematic review and meta-analysis.

OBJECTIVES The relationship between rheumatoid arthritis (RA) and the risk of leukemia was still controversial. This study aimed to assess the risk of leukemia in patients with rheumatoid arthritis by systematic review and meta-analysis. METHODS Relevant studies were identified by searching PubMed, Embase, Cochrane Library, and SinoMed up to December 2019. Random effects model analysis was used to pool standardized incidence ratios (SIRs) and 95% confidence interval. RESULTS A total of 15 relevant studies that met the criteria were included. Compared with the general population, patients with RA showed an increased risk of leukemia (SIR = 1.51, 95% CI: 1.34-1.70). The statistical heterogeneity was moderate with an I2 of 55.5%. In subgroup analysis, the source of heterogeneity may be due to differences in sample size. Publication bias was not found in the Begg funnel plot and the Egger test. CONCLUSION Our findings suggested that the risk of leukemia in RA was increased compared with the general population. Key points • This is the first systematic review and meta-analysis to assess the risk of leukemia in RA. • Our study suggested that the risk of leukemia in RA was increased compared with the general population. • This study indicated that the risk of leukemia in RA was higher in non-Asian populations.