PB1294 - Idiopathic mild platelet dysfunction: Baseline characteristics and clinical courses

Background: Platelet function defects are occasionally found in patients presenting with mild bleeding disorders. After excluding all acquired causes, the presumptive diagnosis is ‘hereditary’ platelet dysfunction despite the genetic basis remains unclear.

Aims: To describe the characteristics and natural history of adult patients with unexplained mild platelet dysfunction.

Methods: This cohort study included adult patients who were diagnosed as platelet dysfunction during 1 September 1995 – 1 March 2022. The exclusion criteria were diagnoses of Glanzmann thrombasthenia, Bernard Soulier syndrome or Von Willebrand disease. Patients who were on drugs or supplements affecting platelet function, uremia, paraproteinemia, myeloid neoplasms (MPN or MDS) or acquire platelet dysfunction with eosinophilia (APDE) were also excluded.

Results: There were the total of 56 patients, 51 of whom (91%) were female with the median age of 28 years (Interquartile range [IQR] 24.5- 38.5). The defective responses to ADP, epinephrine, collagen and arachidonate were found in 91%, 82%, 55% and 34% respectively.
Twenty-one subjects could be contacted and they agreed for the repeat tests. All of them were female (100%) with the median age at diagnosis was 37 years old (IQR 28.5-57). The median follow up time was 6 years (IQR 3-12). The median ISTH BAT bleeding scores at initial diagnosis and at follow-up were 5 (IQR 3-8) and 1 (IQR 0-2.5), respectively. The subnormal responses to ADP, epinephrine, collagen and arachidonate were detectable in 95%, 81%, 71% and 38%, respectively.
Eleven of Twenty-one patients (52.4%) showed complete platelet function recovery on the repeated aggregometry. There were numerical differences between the characteristics of the recovery and non-recovery groups (Table 1).

Conclusion(s): Idiopathic mild platelet dysfunction was female predominant and showed symptom improvement over time. Spontaneous platelet function recovery was observed in approximately half of the patients. Larger studies are required to obtain deeper insights in this condition.