Predictors for and outcomes after bone marrow biopsy in Scandinavian patients with chronic immune thrombocytopenia.

ABSTRACT

OBJECTIVES: To examine predictors for bone marrow biopsy (BMB) and the outcome following BMB in patients with chronic immune thrombocytopenia (cITP). METHODS: We identified patients diagnosed with cITP during 2009-2017 and obtained information on BMB, cITP treatment and subsequent thrombotic events, hospitalized bleeding, hematological cancer, and death using data from population-based healthcare databases and medical records in Denmark, Norway, and Sweden. RESULTS: Among 4471 adults (≥18 years) with cITP, 1683 (37.6%) underwent BMB before cITP diagnosis, while cumulative BMB incidence after cITP diagnosis date was 3.1% at 1 year and 7.5% at 5 years. Predictors of having a BMB after cITP diagnosis included older age, male sex, low baseline platelet count, splenectomy, and number of cITP treatments. Compared with patients without BMB, patients with BMB had higher rates of thrombotic events (1 year adjusted hazard ratio [HR] 1.53 [95% CI, 0.92-2.54]), hospitalized bleeding episodes (1 year adjusted HR 1.72 [95% CI, 1.15-2.58]), hematological cancer (1 year adjusted HR 35.26 [95% CI 17.67-70.34]), and all-cause mortality (1 year adjusted HR 1.97 [95% CI, 1.44-2.68]). CONCLUSION: Patients who undergo BMB after cITP diagnosis represent a subset of patients with more severe disease and increased rates of complications as well as hematological malignancies.