Introduction: Poor adherence to factor replacement therapy among patients with haemophilia can lead to joint bleeding and eventual disability. Aim: The aim of this study was to determine patient-related characteristics associated with adherence to factor replacement in adults with haemophilia. Methods: Adults with haemophilia were recruited to participate in this cross-sectional study. Adherence was measured using either the Validated Hemophilia Regimen Treatment Adherence Scale (VERITAS)-Pro or the VERITAS-PRN questionnaire. Simple and multiple regression analyses that controlled for confounding were performed to determine the association between patient-related characteristics and adherence to factor replacement therapy. Results: Of the 99 subjects enrolled, all were men; 91% had haemophilia A and 78% had severe disease. Age ranged from 18 to 62 years. Most (95%) had functional health literacy; but only 23% were numerate. Mean adherence scores were 45.6 (SD 18) and 51.0 (SD 15) for those on a prophylactic and those on an episodic regimen, respectively, with a lower score indicating better adherence. On multivariable analysis, being on any chronic medication, longer duration followed at our haemophilia treatment centre, higher physician trust and better quality of life were associated with higher adherence. A history of depression was associated with lower adherence. Conclusion: Two potentially modifiable characteristics, physician trust and depression, were identified as motivator and barrier to adherence to factor replacement therapy. Promoting a high level of trust between the patient and the healthcare team as well as identifying and treating depression may impact adherence to factor replacement therapy and accordingly reduce joint destruction.

To assess sources of variability in platelet function tests in normal subjects, 64 healthy young adults were tested on 2-6 occasions at 2 week intervals using four methods: platelet aggregation (AGG) in platelet-rich plasma (PRP) in the Bio/Data PAP-4 Aggregometer (BD) and Chrono-Log Lumi-Aggregometer (CL); and AGG in whole blood (WB) in the CL and Multiplate Platelet Function Analyser (MP), with ATP release (REL) in CL-PRP and CL-WB. Food and medication exposures were recorded prospectively for 2 weeks prior to each blood draw. At least one AGG abnormality was seen in 21% of 81 drug-free specimens with CL-PRP, 15% with CL-WB, 13% with BD-PRP and 6% with MP-WB, increasing with inclusion of REL to 28% for CL-PRP and 30% for CL-WB. Epinephrine AGG and REL were significantly reduced in males (P < 0·0001). Ristocetin AGG and collagen and thrombin REL were significantly reduced in Blacks (P < 0·0001). One-third of specimens drawn following flavonoid-rich food exposures had aberrant results, compared to 8·5% of specimens without such exposures (P = 0·0035). PRP tests had less intra-individual variation than WB tests. Gender, race, diet and test system affected results of platelet function testing in healthy subjects, suggesting caution when interpreting the results of platelet function testing in patients.