Determinants of oral medication compliance in osteoporosis: the role of medication beliefs.

Abstract

As medical technology has advanced and the age structure of the population has increased, much of the focus of medical therapy has shifted from treating acute symptomatic illness to prevention and management of chronic illness. Medications play a central role in the management of many chronic conditions (such as hypertension, hyperlipidemia, non-insulin dependent diabetes, and osteoporosis) that are risk factors for a variety of adverse disease outcomes. Non-compliance to medications has been shown to be a significant impediment to more comprehensive control of these conditions and avoidance of associated adverse health outcomes, and remains poorly understood. Beliefs regarding the potential benefits and harms associated with medications may be an important determinant of medication non-adherence. The relationship between these beliefs and adherence, adjusted for the perceived threat of the target condition and other variables that influence adherence, has not been explicated. The aims of this cross-sectional study of persons prescribed oral bisphosphonate medication to prevent osteoporotic fractures are as follows. Estimate the associations of perceived necessity of and concerns about medication and three aspects of medication use behavior Non-persistence due to side effects Non-persistence for reasons other than side effects Non-compliance (missed doses) Estimate associations of perceived need for medication

Susceptibility to and severity of fractures Patient-provider relationship quality Objective indicators of fracture risk Estimate the associations of patient-provider relationship quality and self-reported adherence Directly Indirectly through other variables A conceptual framework is presented of medication persistence and compliance with fracture prevention medication. Four medication attitude variables, perceived necessity of fracture prevention medication, concerns about the long-term safety of and dependence upon medication, medication use self-efficacy, and perceived medication cost burden were postulated to be predictors of fracture prevention medication use behavior. These attitudinal variables were postulated to be mediating variables between fracture prevention medication use behavior and other predictors, such as perceived susceptibility to and severity of fractures, the patient-provider relationship quality, and objective indicators of fracture risk. Medication persistence and compliance was assessed by self-report, and medication beliefs by a mailed survey. Non-persistence was defined as stopping fracture prevention medication for more than one month, and non-compliance as missing one or more doses over the past 4 weeks. A multivariate path model, consisting of six regression equations, was used to estimate this model. Perceived need for fracture prevention medication was moderately strongly associated with non-persistence due to side effects and for other reasons, but not with non-compliance. Concern about medications was associated with non-persistence due to side effects and with non-compliance, but not with non-persistence for other reasons. Medication use self-efficacy was strongly associated with non-compliance and modestly with non-persistence for other reasons, but not with non-persistence due to side effects. The patient-provider relationship quality was modestly associated with non-persistence, but this effect was indirect through perceived need for fracture prevention medication, concern about medications, and medication use self-efficacy. Documentation of a prevalent vertebral fracture was associated with a higher perceived need for fracture prevention medication, and indirectly with mildly lower self-reported non-persistence. Providers can leverage the trust patients have in them to modestly improve persistence and compliance with fracture prevention medication by assessing whether or not the patient's perceived need for fracture prevention medication is congruent with their actual fracture risk and soliciting and addressing concerns about medications. Wider use of lateral spine imaging to identify clinically unrecognized vertebral fractures may also encourage persistence with fracture prevention medication among that subset of older men and women at highest risk of fracture, and for whom the benefits of fracture prevention medication have been extensively demonstrated.