Does reading patient information leaflets influence adherence and adverse drug reactions in arterial hypertension? A cross-sectional study

INTRODUCTION: Most patients after receiving pharmacotherapy prescription read patient information leaflets (PILs). Many studies highlight the role of the nocebo effect, whereby information on adverse drug reactions (ADRs) increases symptom reporting. OBJECTIVES: The aim of this study was to assess the association between reading PILs, adherence to pharmacotherapy, and the frequency and types of reported ADRs. PATIENTS AND METHODS: This cross-sectional questionnaire-based study included patients receiving inpatient or outpatient care at a hypertension clinic. The analysis included data from 949 individuals (529 female, 420 male) diagnosed with arterial hypertension. RESULTS: Approximately 60% of patients reported reading PILs. Compared with non-readers, they were younger (median age 63 vs 67 years), had a shorter duration of hypertension (median duration 10 vs 11.5 years), and fewer cardiovascular comorbidities, while the prevalence of non-cardiovascular comorbidities and the number of medications prescribed did not differ between groups. PILs readers more frequently reported adherence to medical recommendations (98% vs 61%), although 11% reported self-discontinuation at least once after reading the leaflet. They also reported a lower overall frequency of ADRs (38% vs 57%), mainly driven by fewer allergic and idiosyncratic reactions (23% vs 40%), while pharmacologically predictable ADRs did not differ between groups. CONCLUSIONS: Reading PILs was positively associated with self-reported adherence to medical recommendations and with a lower frequency of reported ADRs. These findings suggest that the beneficial effect of improved adherence associated with reading PILs may outweigh the potential negative impact of the nocebo effect.