Pharmacological agents preceding a diagnosis of immune thrombocytopenia in adult patients developing the chronic form: A Swedish national register study.

Patients with primary chronic immune thrombocytopenia (cITP) have been reported to use more anti-infective medications, even before diagnosis of immune thrombocytopenia (ITP). The more common use of anti-infective medications may be due to general health problems, requiring medication in the early stages of cITP and before the diagnosis is set, rather than infections preceding the disease. Accordingly, cITP may not only be associated with use of anti-infective medications but also with medications for more general symptoms.

OBJECTIVE: To investigate use of medications for general symptoms, such as analgesics and vitamin supplements in patients with ITP developing the chronic form, the year preceding their first primary diagnosis in comparison with such use in the general population.

METHOD: Swedish Health Registers were used to identify adult patients (n=1087) with primary cITP during 2006-2012 and data on medications. Standardized Incidence Ratios (SIRs) and 95% confidence intervals (CI), were estimated as a measure of relative risk.

RESULTS: The association for overall studied medications was SIR=1.36 (95% CI 1.32-1.41). A majority of the point estimates were above unity.

CONCLUSION: In patients with cITP, prescription fills for medications used to treat pain conditions and vitamin deficiencies are more common in the year preceding their first diagnosis as compared with prescription fills in the general population. Our results suggest that patients later diagnosed with cITP receive treatment due to symptoms that could be signs of an early ITP. Accordingly, in investigations for unspecific pain symptoms and vitamin deficiencies, cITP should be considered as a differential diagnosis.