Assessing the multidimensional relationship between medication beliefs and adherence in older adults with hypertension using polynomial regression.

The Necessity-Concerns Framework (NCF) is a multidimensional theory describing the relationship between patients' positive and negative evaluations of their medication, which interplay to influence adherence. Most studies evaluating the NCF have failed to account for the multidimensional nature of the theory, placing the separate dimensions of medication 'necessity beliefs' and 'concerns' onto a single dimension (e.g. the Beliefs about Medicines Questionnaire-difference score model). The purpose of this study was to assess the multidimensional effect of patient medication beliefs (concerns and necessity beliefs) on medication adherence using polynomial regression with response surface analysis. Community-dwelling older adults over 65 years old (n = 1,211), presenting their own prescription for antihypertensive medication to 106 community pharmacies in the Republic of Ireland, rated their concerns and necessity beliefs to antihypertensive medications at baseline and their adherence to antihypertensive medication at 12 months via structured telephone interview. Confirmatory polynomial regression found the difference-score model to be inaccurate; subsequent exploratory analysis identified a quadratic model to be the best-fitting polynomial model. Adherence was lowest among those with strong medication concerns and weak necessity beliefs, and adherence was greatest for those with weak concerns and strong necessity beliefs (slope β = -0.77, p < 0.001; curvature β = -0.26, p = 0.004). However, novel nonreciprocal effects were also observed; patients with simultaneously high concerns and necessity beliefs had lower adherence than those with simultaneously low concerns and necessity beliefs (slope β = -0.36, p = 0.004; curvature β = -0.25, p = 0.003). The difference-score model fails to account for the potential nonreciprocal effects. The results therefore extend evidence supporting the use of polynomial regression to assess the multidimensional effect of medication beliefs on adherence

Prescription drugs with potential for misuse: protocol for a multi-indicator analysis of supply, detection and the associated health burden in Ireland between 2010 and 2020.

INTRODUCTION There is an increasing concern about the misuse of prescription drugs. Misuse refers to the intentional repurposing of prescribed drugs and/or the use of illicitly sourced prescription drugs, which may be counterfeit or contaminated. Drugs with the greatest potential for misuse are prescription opioids, gabapentinoids, benzodiazepines, Z-drugs and stimulants. OBJECTIVE The aim of this study is to provide a comprehensive analysis of the supply, patterns of use and health burden associated with prescription drugs with potential for misuse (PDPM) in Ireland between 2010 and 2020. Three inter-related studies will be carried out. The first study will describe trends in supply of PDPM using law enforcement drug seizures data and national prescription records from national community and prison settings. The second study aims to estimate trends in the detection of PDPM across multiple early warning systems using national forensic toxicology data. The third study aims to quantify the health burden associated with PDPM nationally, using epidemiological indicators of drug-poisoning deaths, non-fatal intentional drug overdose presentations to hospitals and drug treatment demand. METHODS AND ANALYSIS A retrospective observational study design, with repeated cross-sectional analyses, using negative binomial regression models or, where appropriate, joinpoint regression