Relative risk of myelodysplastic syndromes in patients with autoimmune disorders in the General Practice Research Database

Background: Certain immunosuppressant drugs are known to increase the risk of myeloid neoplasms although it is unclear if underlying autoimmune disorder itself increases the risk of myeloid neoplasms. Methods: Using a nested case-control study in the General Practice Research Database (GPRD), we estimated the relative risk of myeloid neoplasms, specifically myelodysplastic syndromes (MDS) in patients with autoimmune disorders compared with patients without autoimmune disorders. Results: We identified 849 cases of MDS and 3417 matched controls. There was a slightly increased risk of MDS in patients with any autoimmune disorder (adjusted OR 1.5, 95% CI 1.1, 2.0), which was limited to patients diagnosed over 10 years prior to the index date (adjusted OR 2.1, 95% CI 1.4, 3.2). The elevated odds ratios of MDS were present in both untreated patients and patients who had a record of receiving multiple treatments. Conclusion: There was a modestly increased risk of MDS was in patients with a history of autoimmune disorder. However, it is difficult to determine whether autoimmune disorders increased the risk of MDS, or whether the small elevation in the risk estimate was an artifact of misdiagnosis resulting from early MDS symptoms similar to those of autoimmune disorders. Impact: These findings may indicate the increased need for MDS screening in patients with autoimmune disease, and further research regarding MDS etiology.