Retrospective, multicohort analysis of the Clinical Practice Research Datalink (CPRD) to determine differences in the cost of medication wastage, dispensing fees and prescriber time of issuing either short (<60 days) or long (≥60 days) prescription lengths in primary care for common, chronic conditions in the UK

Objectives: To investigate patterns of early repeat prescriptions and treatment switching over an 11-year period to estimate differences in the cost of medication wastage, dispensing fees and prescriber time for short (<60 days) and long (≥60 days) prescription lengths from the perspective of the National Health Service in the United Kingdom. Setting: Retrospective, multiple cohort study of primary care prescriptions from the Clinical Practice Research Datalink. Participants: Five random samples of 50,000 patients each prescribed oral drugs for (1) glucose control in type 2 diabetes mellitus (T2DM), (2) hypertension in T2DM, (3) statins (lipid management) in T2DM, (4) secondary prevention of myocardial infarction and (5) depression. Primary and secondary outcome measures: The volume of medication wastage from early repeat prescriptions and three other types of treatment switches was quantified and costed. Dispensing fees and prescriber time were also determined. Total unnecessary costs (TUC, cost of medication wastage, dispensing fees, and prescriber time) associated with