Characteristics and Outcome of Newly Diagnosed Immune Thrombocytopenia in Adults: Results from a Nationwide Prospective Cohort Study

Objectives

The objectives of the study were (1) to describe the clinical features of adult patients presenting with an immune thrombocytopenia (ITP), (2) to explore the predictors of chronicity and (3) to determine whether a family history of autoimmune disorder was a risk factor of ITP.

Methods

An observational prospective cohort study was conducted in France nationwide. During more than two years, 21 participating physicians from haematology centres recruited all consecutive adults of 18 years old or above, diagnosed with an incident episode of ITP. Data were collected at baseline and 12 months, regarding socio-demographic characteristics, personal and familial medical history, clinical and biological signs of ITP and its medical management, left at the discretion of each physician. Data were collected after 12 months clinical, biological signs of ITP and current medication, from which the outcome was derived: chronicity or recovery.

Predictors of chronicity at baseline were explored using univariate logistic regression models, providing the Odds Ratio (OR) and their 95% Confidence Intervals (95%CI). To explore whether having a history of autoimmune disorder in first-degree relative was a risk factor of developing an ITP, referent-patients were drawn from a general practice setting database and matched to ITP-patients (10-1). The risk of developing an ITP was explored using univariate conditional logistic regression models, providing the OR and their 95%CI.

Results

153 patients were included over a 28-month period: 94 (61%) patients were female, mean age was 48 years (SD=18.8), and 128 (84%) presented with bleeding symptoms at diagnosis. The median platelet count was 10×10⁹/L. An initial treatment was required in nearly 90% of patients. After 12 months, only 36% of patients were cured without receiving any disease-modifying treatment. The baseline predictors of chronicity at 12 months were a lower platelet count (OR, 1.0; 95%CI, 1.0-1.2) and mucocutaneous bleeding (OR, 0.3; 95%CI, 0.1-1.0). No significant association was found between a history of autoimmune disorder in a first degree relative or the presence of anti-nuclear antibodies and the risk of developing a chronic ITP.

Conclusions

ITP in adults affects patients with a wide age range, mainly female. ITP is a serious disease in adults with a chronic evolution in a majority of patients that is in contrast with children. Low platelet count and severity of bleeding at the diagnosis were associated with a lower risk of chronic evolution.