Letter to the Editor: Excellent response to treatment with hydroxychloroquine in pediatric patients with SLE-related immune thrombocytopenia Aimen Waqar Khan1, Shireen Asifa2, Fatima Monis1, Fareena Wazir3 and Iqra Muneer2AFFILIATION : 1Department of Medicine, Jinnah Sindh Medical University, Karachi, Pakistan.2Department of Medicine, Dow University of Health Sciences, Karachi, Pakistan. 3Department of Medicine, Sir Syed College of Medical Sciences for Girls, Karachi, Pakistan.Dear Editor,We have read with great enthusiasm your study titled “Excellent response to treatment with hydroxychloroquine in pediatric patients with SLE-related immune thrombocytopenia ” by Brik-Simon et al [1]. It was truly an honor to read such a detailed and methodical study that explored the platelet count response and safety of hydroxychloroquine (HCQ) in treating pediatric patients with systemic lupus erythematosus (SLE) related immune thrombocytopenia (ITP). However, after critical appraisal, we believe that certain points warrant discussion in order to alert clinicians and researchers regarding the conclusions drawn.As noted, platelet count response was the main metric outcome in assessing the safety and efficacy of HCQ. While this is pertinent to evaluating how well the said drug manages pediatric ITP, we believe other metrics like quality of life, long-term prognosis, and bleeding severity could offer a more thorough assessment of therapy efficacy [2]. Secondly, it is to be acknowledged that although no side effects linked to HCQ medication were reported, the short follow-up period and retrospective design may have hampered proper safety evaluation. It is therefore important to closely monitor and report long-term safety data on the use of HCQ in pediatric patients including potential eye damage and cardiomyopathy [3]. Furthermore, as females made up the vast majority of patients recruited, the study does not clearly elucidate whether the platelet count was measured keeping menstrual variability in mind and if so, whether the time of measurement was kept constant throughout. It is important to have done so as studies have demonstrated inter-menstrual variability in platelet counts attributable to the physiological changes in hormonal levels [4]. In addition to the number of platelets, we believe bleeding severity should have also been included. Moreover, females have been physiologically reported to have higher platelet counts than men [5] – an important confounder that must be borne in mind. Also, adherence to therapy in this study was assessed by self-reports. When it comes to adherence to medications by self-reports, there are concerns over the validity of the results due to memory recall biases and a tendency to overestimate the patient’s routine in taking the medication. There can also be differences in question phrasing and recall time intervals [6] therefore raising doubts over the validity of the findings reported. Finally, the duration of ITP at HCQ initiation is also different for patients, ranging from .75 to 52 months. Studies have shown that in up to 70-80% of children ITP usually resolves within 6 months [7].To conclude, while we commend the authors’ efforts in conducting this study, we believe addressing the aforementioned limitations will greatly help enhance the credibility of the findings and guide future researches in providing a more refined insight into this topic.