BackgroundMedication prescribing and dispensing often regarded as one of the most effective ways to manage and improve population health. Prescribed and dispensed medications can be monitored through data linkage for each patient. We hypothesised that changes in patient care resulting from COVID-19, changed the way patients access their prescribed medication.Objective To develop an efficient approach for evaluation of the impact of COVID-19 on drug dispensing patterns.MethodsRetrospective observational study using national patient-level dispensing records in Wales-UK. Total dispensed drug items between 01-Jan-2016 and 31-Dec-2019 (counterfactual pre-COVID-19) were compared to 2020 (COVID-19 year). We compared trends of dispensed items in three main British National Formulary (BNF) sections(Cardiovascular system, Central Nervous System, Immunological & Vaccine) using European Age-Standardized rates. We developed an online tool to enable monitoring of changes in dispensing as the pandemic evolves.ResultAmongst all BNF chapters, 52,357,639 items were dispensed in 2020 compared to 49,747,141 items in 2019 demonstrating a relative increase of 5.25% in 2020(95%CI[5.21,5.29]). Comparison of monthly patterns of 2020 and 2019 dispensed items showed a notable difference between the total number of dispensed drug items each month, with an average difference (D) of +290,055 and average Relative Change (RC) of +5.52%. The greatest RC was observed in a substantial March-2020 increase (D=+1,501,242 and RC=+28%), followed by second peak in June (D=+565,004, RC=+10.97%). May was characterised by lower dispensing (D=-399,244, RC=-5.9%). Cardiovascular categories were characterised, across all age groups, by dramatic March-2020 increases, at the epidemic peak, followed by months of lower than expected dispensing, and gradual recovery by September. The Central Nervous System category was similar, but with only a short decline in May, and quicker recovery. A stand-out grouping was Immunological and Vaccine, which dropped to very low levels across all age groups, and all months (including the March dispensing peak).ConclusionsAberration in clinical service delivery during COVID-19 led to substantial changes in community pharmacy drug dispensing. This change may contribute to a long-term burden of COVID-19, raising the importance of a comprehensive and timely monitoring of changes for evaluation of the potential impact on clinical care and outcomes