Factors associated with gender differences in medication adherence: a longitudinal study

Aims. To examine gender differences in the medication adherence of patients with hypertension by applying a longitudinal follow-up. Background. Patient views of illness affect their adherence to therapeutic regimens. However, few studies have explored these issues by using a longitudinal design or from a gender perspective. Design. This study used a longitudinal, correlational design. Methods. A purposive sampling of 118 patients were recruited from cardiovascular clinics of a teaching hospital in Central Taiwan in 2007-2009. Data were collected using the Chinese Illness Perception Questionnaire-Revised and the Medication Adherence Inventory at three time points: at the first clinic visit, 6 and 12 months after the initial survey. Generalized estimating equations were calculated using the STATA software for data analysis. Results. The findings revealed that male patients adhere more effectively to medications than female patients do. The interaction between systolic blood pressure and gender emerged as a significant predictor of adherence. Factors associated with adherence in male patients included less causal attribution to culture, more attribution to risk factors, fewer symptoms and uncertain symptoms related to high blood pressure, lower scores for timeline-cyclical and higher scores for illness consequences and coherence. Medication adherence for female patients was significantly related to more causal attribution to balance and risk factors, less personal control and enhanced illness coherence. Conclusion. Factors associated with adherence to antihypertensive medication were relatively gender-specific. Awareness of the differences is crucial for health professionals to provide appropriate advice for patients to cope effectively with their health threat.