The efficacy of hydroxychloroquine in paediatric chronic immune thrombocytopenia: A retrospective cohort study.

Aims: Research on hydroxychloroquine (HCQ) for children with chronic immune thrombocytopenia (ITP) is limited. The association between antinuclear antibody (ANA) positivity and its efficacy remains unclear.

Methods: This retrospective cohort study compared the clinical characteristics of children with chronic ITP who received HCQ with those who did not, as well as patients who responded to HCQ at 3 months with those who did not. Mixed-effects models were performed to assess the effect of HCQ on platelet counts and the association between ANA and its efficacy. Records of HCQ-related side effects were reviewed.

Results: A total of 191 children with chronic ITP were included in this study, including 42 patients who received HCQ. At the last follow-up, 69.0% of patients treated with HCQ achieved complete response or response, with a median follow-up time of 56 months (range: 17-146 months), a higher frequency compared to 48.3% of patients who were not treated with HCQ (odds ratio [OR], 2.39; 95% confidence interval [CI], 1.15-4.95). The overall response rates to HCQ were 56.8% (21/37) at 3 months and 40.5% (15/37) at 1 year. HCQ was effective for increasing platelet counts (mean difference: 23.82 × 10⁹/L; 95% CI: 7.44-40.21), but the association between ANA positivity and its efficacy was not found. Side effects were recorded in six patients (14.3%).

Conclusions: HCQ was associated with increased platelet counts in chronic ITP children. The baseline ANA level was not found to be associated with the efficacy of HCQ. Side effects of HCQ warrant consideration.