Treatment Patterns Among Patients with Immune Thrombocytopenia (ITP) in the United States: An Electronic Medical Record (EMR)-Based Analysis

Introduction

ITP is an autoimmune disorder characterized by platelet destruction and impaired production. Some patients with ITP are refractory or unresponsive to existing therapies, indicating significant unmet medical needs. An assessment of current real-world treatment patterns among patients with ITP should enhance understanding of the ITP disease population and current unmet need. Here we present real-world data describing the ITP population in the United States in terms of demographic and clinical characteristics and use of available ITP therapies.

Methods

This was a longitudinal, retrospective, observational cohort study utilizing data from the Optum® Clinformatics® claims database. Patients with newly diagnosed ITP were included; defined as patients with ≥1 inpatient claim or ≥2 outpatient claims within 90 days of ITP-related diagnosis codes (International Classification of Diseases [ICD], Ninth and Tenth Revision; ICD-9: 287.3x; ICD-10: D69.3x or D69.4x) between October 1, 2015 and March 31, 2020. The index date was the date these criteria were met. Patients were excluded if they had <12 months continuous coverage or any record of thrombopoietin receptor agonist (TPO-RA) use before the index date. All patients were required to have ≥1 prescription during follow-up. Primary ITP was defined as patients who met the inclusion criteria and also had no ICD codes for secondary ITP, and no causes of secondary ITP in an identified time period prior to the index date. Here we describe clinical characteristics and medication use among newly diagnosed patients with primary ITP and the proportion of patients who went on to develop persistent (90 days to <12 months) or chronic (≥12 months) ITP.

Results

There were 19,376 newly diagnosed patients who met inclusion criteria; 15,798 (82%) had primary ITP and 3,578 (18%) had secondary ITP. Among patients with primary ITP, median (min-max) duration of follow-up was 16 (0-55) months and 61% had ≥12 months of follow-up (median duration: 26 months). At baseline, mean (standard deviation [SD]) age was 67 (16) years and 53% of patients were male. Mean (SD) Charlson Comorbidity Index (CCI) was 0.94 (1.41) and 11% of patients fell into a CCI category ≥3. The most common comorbid conditions were hypertension (60%), cardiovascular disease (37%), diabetes (29%), and anemia (27%). The most commonly used concomitant medications were lipid-lowering medications (44%), pain medications (24%), corticosteroids (23%), and anticoagulants (11%). During follow-up, use of these medications increased (lipid-lowering medications [46%], pain medications [38%], corticosteroids [39%], and anticoagulants [15%]). The most commonly used ITP medications during follow-up were corticosteroids (33%), rituximab (3.3%), TPO-RA (2.8%), immunosuppressants (2.6%), intravenous immunoglobulin (2.5%), and immunomodulators (2.4%). There were 1935 (12%) deaths during follow-up, and 87 (0.6%) patients underwent a splenectomy. Of the patients with ≥12 months of follow-up (n=9610), 16% and 32% developed persistent ITP and chronic ITP, respectively. Among the patients with persistent/chronic ITP and ≥12 months of follow-up, 242 (5.3%) received TPO-RA during follow-up. Of these, 93% concomitantly received ≥1 additional ITP treatment-related medication (TRM), 73% of the patients who received TPO-RA and ≥1 other TRM received ≥2 additional ITP TRMs, and 68% of patients who received TPO-RA and ≥2 other TRMs received ≥3 additional ITP TRMs. Of the 242 patients with ≥12 months of follow-up and persistent/chronic ITP who received TPO-RA, 55 (23%) either received an additional TPO-RA therapy or received another newly initiated ITP-related medication ≥30 days after starting TPO-RA.

Almost half of the patients with primary ITP developed persistent/chronic disease. However, only a small percentage of these patients in the Optum® Clinformatics® claims database with no history of TPO-RA use received TPO-RA during follow-up. The majority of patients treated with TPO-RA received ≥1 other ITP TRM during follow-up and nearly 1 in 4 persistent/chronic patients receiving TPO-RA required ≥1 additional TPO-RA or switched to another ITP medication.

Conclusion

Even with the availability of many ITP drug therapies, there is still a considerable current unmet need for effective treatments among patients with primary ITP.

The authors acknowledge Rajeshwari Punekar for contributions to study design.