Measuring the influence of expectations, beliefs, and medication side effects on the risk for drug discontinuation among individuals starting new medications.

ObjectivesTo measure the impact of beliefs, expectations, side effects, and their combined effects on the risk for medication non-persistence. DesignA population-based questionnaire. Setting and ParticipantsIndividuals from Saskatchewan, Canada who started a new antihypertensive, cholesterol-lowering, or antihyperglycemic medication were surveyed about risk factors for non-persistence including: (a) beliefs measured by a composite score of three questions asking about the threat of the condition, importance of the drug, and harm of the drug; (b) incident side effects attributed to treatment; and (c) expectations for side effects before starting treatment. Descriptive statistics and logistic regression models were used to quantify the influence of these risk factors on the outcome of non-persistence. Odds ratios (OR) and 95% confidence intervals (CI) were estimated. Main Outcome MeasureSelf-reported medication non-persistence. ResultsAmong 3,029 respondents, 5.9% (n=179) reported non-persistence within four months after starting the new drug. After adjustment for numerous covariates representing socio-demographics, healthcare providers, medication experiences and beliefs, both negative beliefs (OR 7.26, 95% CI: 4.98 to 10.59) and incident side effects (OR 8.00, 95% CI 5.49 to 11.68) were associated with the highest odds of non-persistence with no evidence of interaction. In contrast, expectations for side effects before starting treatment exhibited an important interaction with incident side effects following treatment initiation. Among respondents with incident side effects (n=741, 24.5%), the risk for early non-persistence was 11.5% if they indicated an expectation for side effects before starting the medication compared to 23.6% if they did not (adjusted OR 0.38, 95% CI 0.25 to 0.60). ConclusionsExpectations for side effects may be a previously unrecognized but important marker of the probability to persist with treatment. A high percentage of new medication users appeared unprepared for the possibility of side effects from their new medication making them less resilient if side effects occur. What is already known on this topicO_LIPrior expectations for side effects are thought to increase the risk for nocebo effects and increase the risk for medication non-persistence. C_LIO_LIMedication non-persistence remains a major threat to patient outcomes. C_LI What this study addsO_LIExpectations for side effects from medications may be a previously unrecognized protective factor against non-persistence. C_LIO_LIA high percentage of new medication users appear unprepared for the possibility of side effects from their new medication making them less resilient if side effects occur. C_LI