Characterising the use of varenicline: an analysis of the Australian dispensing claims data.

Abstract

Background and aimsIn Australia, patterns of use of smoking cessation medications and factors associated with their dispensing are currently not known. This study aimed to measure the demographic and clinical factors associated with varenicline dispensing compared with nicotine replacement therapy (NRT) and bupropion among first‐time users of Pharmaceutical Benefits Scheme (PBS) subsidised smoking cessation medicines in Australia and to characterise those who discontinued varenicline treatment prematurely.DesignRetrospective, population‐based study. Logistic regression was used to identify factors associated with varenicline dispensing compared with NRT and bupropion. Sensitivity analyses estimated the proportion of individuals who completed the recommended 12 weeks of varenicline treatment.Setting and participantsFirst‐time users of PBS subsidised smoking cessation medicines in Australia. Individuals first dispensed a smoking cessation medicine between 2011 and 2019 were identified from a 10% random sample of the national dispensing claims data.MeasurementsThe outcome for the regression analysis was the dispensing of varenicline compared with NRT and bupropion. The dispensing of a smoking cessation medicine was identified using the World Health Organization Anatomical Therapeutic Chemical Classification System and PBS item codes. Independent variables included demographic and clinical characteristics such as sex, age, concessional status, year of treatment initiation and comorbidities identified using the Rx‐Risk index. The proportion of people who discontinued varenicline treatment after the initiation pack was determined using prescription refill data.FindingsA total of 94 532 people had their first PBS subsidised smoking cessation medicine. Of these, 62 367 (66.0%) were dispensed varenicline, 29 949 (31.7%) NRT and 2216 (2.3%) bupropion. The odds of varenicline dispensing were higher in males (OR, 1.18; 95% CI, 1.14–1.21), but lower in older adults (0.86 [0.82–0.90] in above 30 years to 0.49 [0.47–0.52] in 61 years and above), among concession beneficiaries (0.44; 0.43–0.46), and those with congestive heart failure (0.60; 0.53–0.68), depression (0.61; 0.54–0.69), anxiety (0.70; 0.66–0.73), psychotic illness (0.39; 0.37–0.42), and chronic obstructive pulmonary disease (0.87; 0.82–0.92). The majority (37 670; 60.4%) of those dispensed varenicline discontinued treatment after the initiation pack. Anxiety and psychotic illnesses were significantly more prevalent in those who discontinued treatment. Only 2804 (4.5%) of those dispensed varenicline completed 12 weeks of treatment.ConclusionIndividuals dispensed varenicline in Australia appear to be healthier compared with those who are dispensed nicotine replacement therapy or bupropion.