Associations Between Regularity of General Practitioner Contacts and Adherence to Statin Therapy

Abstract

IntroductionResearch has demonstrated continuity and regularity of general practitioner (GP) contacts to be associated with reduced hospitalisations and emergency department (ED) presentations. Opportunities for improved medication management are often cited as a potential causal mechanism, but little research has directly addressed this.
 Objectives and ApproachTo determine associations between continuity of primary care and adherence with statin medications amongst individuals at risk of cardiovascular disease outcomes, taking statins through the exposure period of July 2011 - June 2012. We used self-report and administrative data from 267,153 participants of the 45 and Up Study conducted in New South Wales, Australia from 2006-2009. Medicare Benefits Schedule and Pharmaceutical Benefits Scheme data, from the Australian Government Department of Human Services, were linked to survey, hospital and death data by the NSW Centre for Health Record Linkage. Exposures were the Usual Provider of Care (UPC) index, i.e. the proportion of visits made to the usual GP; and a regularity index assessing whether patients were visiting the GP on a regular basis. Cox regression estimated associations between these exposures and time to cessation of statin medication, defined as a 30-day period without supply.
 ResultsPreliminary findings amongst a cohort of approximately 48,000 indicated that increases in both regularity and continuity of primary care were associated with reduced likelihood of statin cessation. After controlling for socio-demographic and health status indicators the hazard ratio for cessation in the most regular quintile (baseline least) was 0.84 (95%CI 0.80 – 0.87) and in the highest continuity quintile was 0.93 (95%CI 0.89 – 0.96).
 Conclusion / ImplicationsPrevious work assessed relationships between continuity of care and downstream hospital and ED outcomes. This work complements existing literature by assessing intermediate outcomes, aiding understanding of potential causal pathways. These findings are relevant given adherence to statin medication is often sub-optimal.