The risk of systemic lupus erythematosus (SLE) was higher for patients with idiopathic thrombocytopenic purpura (ITP) in a report published in the Annals of Rheumatic Diseases.

Patient data for this retrospective cohort analysis were examined from the National Health Insurance Research Database in Taiwan. There were 723 patients with ITP included in the analysis and 14,460 patients who did not have ITP and represented the control group. The researchers analyzed patient records to determine if there was a relationship between ITP and an incident diagnosis of SLE. Analyses of the entire patient population were matched by age and sex. A propensity score-matched analysis was also performed, which included 668 patients with ITP and 1336 without ITP.

The mean follow-up times were 76.85 months for the ITP group and 86.20 months for the non-ITP group. The ITP group showed a significantly greater cumulative incidence of SLE compared with the non-ITP group (P <.0001). The SLE incidence were 4.7% and 0.19% among ITP and non-ITP groups, respectively, which translated into incidence rates per 100,000 person-months of 62.0 in the ITP group and 2.10 in the non-ITP group.

Patients with ITP had an adjusted hazard ratio (aHR) of 25.1 for incidental SLE in the main analysis and an aHR for incidental SLE of 17.4 for the propensity score-matched analysis.

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In addition, patients who were women (aHR, 20.5) and patients with Sjogren syndrome (aHR, 6.02) also had a higher SLE risk.

“This study demonstrated that patients with ITP are at a higher risk of SLE. Clinically, patients with ITP should be educated and monitored for the risk of incidental SLE,” concluded the researchers.

Reference

Zhu FX, Huang JY, Ye Z, Wen QQ, Wei JC. Risk of systemic lupus erythematosus in patients with idiopathic thrombocytopenic purpura: a population-based cohort study [published online April 2, 2020]. Ann Rheum Dis. doi: 10.1136/annrheumdis-2020-217013