Methods
Ethical consideration
This study represents secondary analysis of the information retrieved from publicly available anonymised datasets and does not warrant formal ethical approval.
Study Design and Population
A longitudinal study of national primary care prescribing datasets were undertaken using NHS Digital sources, namely- OpenPrescribing.net and Prescription Cost Analysis (PCA) [10,11]. OpenPrescribing.net is a national online prescribing data resource hosted by the Evidence-Based Medicine DataLab at the University of Oxford. The resource provides general practice level prescribing data which is published each month from NHS Digital for all prescriptions written by general practitioners and other non-medical prescribers who are attached to the practices. This includes the number of items prescribed and the actual cost of the medication [12]. PCA statistics are provided by NHS Digital and present prescription data regarding the number of items and the net ingredient cost (NIC) of all prescriptions dispensed by the NHS in the community in England [13].
Data Extraction and Analysis
Prescription data from January 2009 to December 2019 for anti-dementia drugs, relating to British National Formulary (BNF) Section 4.11 [14], were included. Data on donepezil, galantamine, rivastigmine and memantine were extracted. Prescription patterns relating to 10 of the most and the 10 of the least deprived Clinical Commissioning Groups (CCGs) as per the Office of National Statistics (ONS) Index of Multiple Deprivation (IMD) in 2015 [15] (Supplemental material 1) were also extracted and analysed to explore the link between prescribing patterns and deprivation. The CCGs are clinically-led autonomous NHS bodies involved in planning and commissioning healthcare services for their locality. The 10 most deprived and the 10 least deprived CCGs included in the analysis covered a population of 2.8 million and 2.3 million respectively. All data were adjusted for population estimates for each year at national, regional and CCG level [16]. Costs of prescription items were adjusted for inflation using the ONS Consumer Price Index (CPI) for pharmaceutical products [17]. Dementia prevalence for 2017-18 data was obtained from Quality and Outcomes Framework Datasets [18] All data were extracted, independently checked for accuracies and analysed using Microsoft Excel and SPSS V21. The Independent-Sample Median test was used to analyse the differences in the median value for prescription items and costs across NHS England Commissioning Regions for each year. The Independent-Samples Mann-Whitney U Test was used to examine the variation in prescription items and costs across categories of the most and least deprived areas in England. P values of <0.05 were considered significant. Data trends on antipsychotic drugs, including haloperidol and risperidone, were also similarly extracted and analysed to be used as a comparator drug class.