Trends in emergency hospital admissions in England due to adverse drug reactions: 2008–2015

Objectives: To determine the scale of adverse drug reaction (ADR)-related emergency hospital admissions in England from 2008 to 2015 using the Hospital Episode Statistics (HES) database. Methods: Part of the HES database contains information about all hospital admissions in England. Annual data are published online and are publically available. These hospital admission data were analysed to determine how many emergency admissions were due to ADRs. International classification of diseases, 10th edition (ICD-10) codes that indicated a drug was the primary cause of the admission were included in the study. Key findings: The total number of emergency hospital admissions increased by 12.1%, from 5 010 670 in 2008/2009 to 5 615 707 in 2014/2015. Over the same period, emergency admissions due to ADRs increased by 53.4%, from 60 055 in 2008/2009 to 92 114 in 2014/2015. These figures indicate an increase in the proportion of emergency hospital admissions due to ADRs over the period of study, from 1.2% in 2008/2009 to 1.6% in 2014/2015. The total number of bed days utilised decreased by 7.1%, from 51 841 443 in 2008/2009 to 48 183 084 in 2014/2015. Despite this overall decrease, the number of bed days that were used due to ADRs increased by 51.5% from 625 011 (1.2% of all bed days) in 2008/2009 to 947 016 (2.0% of all bed days) in 2014/2015. The most common ADRs were mental and behavioural disorders due to drugs and the drugs most commonly implicated in ADRs were systemic agents such as anticancer drugs and immunosuppressants. Conclusions: This study demonstrates that emergency hospital admissions due to ADRs are an increasing problem for the National Health Service (NHS) in England and further research is needed to discover which interventions are most likely to reduce them.