Introduction Patient medication adherence is essential for the effectiveness of therapeutic interventions. Patients' perceptions of the necessity of the prescribed treatments and concerns about the potential adverse effects are modifiable psychological factors that can influence adherence to treatment recommendations. Primary immune thrombocytopenia (ITP) is defined by immune-mediated platelet destruction, resulting in thrombocytopenia and an elevated risk of bleeding. Therapeutic strategies focus on controlling acute bleeding and mitigating long-term hemorrhagic risk. However, little is known about adherence behavior or the influence of medication beliefs on adherence in patients with ITP. Therefore, we investigated medication adherence and beliefs about medicines in this population and examined the relationship between them.

Methods This multicenter, cross-sectional study included 135 adult patients with ITP recruited from 12 hematology outpatient clinics across Greece. Eligible participants had been diagnosed with chronic or persistent ITP according to internationally recognized criteria and had been self-administering prescribed treatment for their condition for at least one month prior to study enrollment. Participants were asked to complete a demographic questionnaire, the five-item Medication Adherence Report Scale (MARS; score range: 5–25), and the Beliefs about Medicines Questionnaire Specific (BMQ; score range: 5–25 per subscale). Clinical data were collected by treating physicians. All variables were summarized using descriptive statistics. Multiple linear regression analysis was performed to identify factors associated with the total MARS score. Statistical significance was set at α = 0.05.

Results The mean (SD) age of the participants was 57.1 (17.6) years; 62.2% were female and 80.7% reported not living alone. The median (min, max; IQR) duration of the disease and the duration of the treatment were 43 (3, 350; 97) and 10 (1, 156; 25) months, respectively. The most common route of medication administration was oral (79.9%) and the most common dosing schedule was daily or more than once/week (79.3%). The median (min, max; IQR) platelet count was 112.000 (1.000, 450.0000; 101.000). Overall, 91.1% of patients were in chronic phase and were receiving thrombopoietin receptor agonists.

The mean (SD) total MARS score was 23.3 (2.5). Regarding specific MARS items, 94.1% of patients reported that they never or rarely forget to take their ITP medication and 91.8% reported that they never or rarely take less medication than prescribed. In contrast, 38.4% of participants reported that they always, often or sometimes adopted one or more non-adherent behaviors.

The mean (SD) total scores of the BMQ necessity and BMQ concerns subscales were 19.5 (4.0) and 14.8 (4.6), respectively. The mean (SD) necessity-concerns differential (NCD) score was 4.7 (5.2). Regarding individual necessity items, 88.2% of participants were in agreement with the fact that their medicines protect them from becoming worse and 82.2% were in agreement with the fact that their health, at present, depends on their medicines. Regarding specific concern items, 66.7% of the participants were in agreement with the fact that they sometimes worry about long term effects of their medication and 48.1% were in agreement with the fact that having to take medicines worries them. Multiple linear regression models adjusted for age, gender, living conditions, disease duration, treatment duration and route of administration demonstrated that total BMQ necessity subscale score was significantly positively associated with total MARS score (β = 0.143, p = 0.017).

Conclusions This study found a high level of medication adherence and strong necessity beliefs about medicines among patients with ITP. The positive NCD score suggested that patients' beliefs about the necessity of their medication were stronger than their concerns. However, more than half of participants were concerned about the long-term effects of their medications. A positive association between necessity beliefs and adherence was also observed, suggesting that patients with stronger necessity beliefs about their treatment tend to be more adherent to their prescribed regimen. Longitudinal and interventional studies are required to explore whether strengthening patients' beliefs about the necessity of their prescribed medication could improve adherence behavior in ITP patients.

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2025
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