Influence of socioeconomic factors on the adherence of alendronate treatment in incident users in Norway

Abstract

Purpose: To examine whether socioeconomic factors influence adherence to alendronate drug treatment among incident users in Norway during 2005-2009.

Methods: The study included 7610 incident alendronate users in 2005 (40-79 years), followed until 31 December 2009. Mean age was 66.6 years, and 86.7% of the patients were women. Data were drawn from the Norwegian Prescription Database and linked to marital status, education and income. Adherence was measured by the medication possession ratio (MPR). MPR was defined as the number of dispensed defined daily doses divided by the number of days each patient was included in the study. A patient was adherent if MPR ≥ 80%. ORs with 95%CI were estimated using logistic regression.

Results: Among all patients, 45.5% was adherent throughout 4.2 years. A slightly higher proportion of women than men were adherent. Adjusted for all covariates, women aged 70-79 years had an OR of 1.27 (95%CI 1.10-1.45) for adherence compared with those 40-59 years. In women, high household income predicted adherence of alendronate use. In men, a middle educational level compared with a low level, predicted adherence (adjusted OR = 1.47 (95%CI 1.10-1.96)). After adjustments, previous marriage reduced the odds of being adherent compared with present marriage, in both men and women.

Conclusions: In women, the most important factors for being adherent were high age and high income. In men, a middle educational level predicted adherence. Previous marriage reduced the odds of being adherent in both women and men.