Affiliation:
1. Division of Medical Oncology and Hematology Princess Margaret Cancer Centre Toronto Ontario Canada
2. ICES Toronto Ontario Canada
3. Division of Medical Oncology and Hematology Unity Health Toronto Ontario Canada
4. Li Ka Shing Knowledge Institute Toronto Ontario Canada
5. Leslie Dan Faculty of Pharmacy University of Toronto Toronto Ontario Canada
6. Institute of Health Policy, Management and Evaluation University of Toronto Toronto Ontario Canada
7. Department of Pediatrics Weill Cornell Medical College New York New York City USA
Abstract
SummaryInternational societies have conflicting recommendations on whether bone marrow aspirate/biopsy (BMB) is needed during workup for isolated thrombocytopenia. Our objective was to determine if thrombocytopenia in patients aged ≥60 years is associated with an increased incidence of haematological malignancy. We performed a retrospective population‐based cohort study in patients aged ≥60 years between January 1, 2009 to December 31, 2019. Exposed patients had specialist consultation for thrombocytopenia, with platelet count <100 × 109/L, but normal haemoglobin and white blood cell count. Unexposed patients were those who never had specialist consultation for thrombocytopenia and whose platelets were ≥100 × 109/L. The primary outcome was the diagnosis of haematological malignancy using a competing risk of death model. During 4.0 years (IQR 2.2–6.7) of follow‐up, 378/4930 exposed (19.1/1000PY, 95% CI 17.1–21.0), and 204/17556 unexposed patients (2.5/1000PY, 95% CI 2.2–2.8) were diagnosed with haematological malignancy (HR 15.5 (95% CI 11.3–21.4, p < 0.0001) in year 1, and 5.3 (95% CI 4.4–6.6, p < 0.0001) in years 2+). This finding persisted in analyses stratified by sex, age, severity, or duration of thrombocytopenia, and treatment with corticosteroids within 2 weeks of consultation. This study found a strong association between isolated thrombocytopenia and haematological malignancy in patients ≥60 years, supporting consideration of diagnostic testing including BMB during outpatient specialist consultation.