Bidirectional relationship between systemic lupus erythematosus and non-Hodgkin's lymphoma: a nationwide population-based study.

OBJECTIVES: We conducted this nationwide population-based study in Taiwan to investigate whether there is a bidirectional relationship between SLE and non-Hodgkin's lymphoma (NHL).

METHODS: Using the National Health Insurance Research Database of Taiwan, we identified 16 417 patients with new-onset SLE without previous cancer and 25 069 patients with new-onset NHL without previous SLE as two non-overlapping cohorts from 1998-2012, and followed them until 2013. Standardized incidence ratio (SIR) for NHL in the patients with SLE and SIR for SLE in the patients with NHL were compared with the general population.

RESULTS: Among the 16 417 patients with SLE, 512 developed cancers, including 34 with NHL. The highest SIR was that for NHL (SIR 4.2, 95% CI 2.9, 5.9) in site-specific cancer risk analysis. Among the 25 069 patients with NHL, 14 developed SLE, and the SIR was also increased (SIR 2.0, 95% CI 1.1, 3.4). The SIRs of the patients with SLE to develop NHL and the patients with NHL to develop SLE were both highest within the first year after the diagnosis of each disease.

CONCLUSION: This nationwide population-based study is the first study to report a bidirectional relationship between SLE and NHL. This finding may suggest being alert for the patients with SLE or NHL who have early sings of the other disease in clinical care.