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.