Polypharmacy is most commonly reported as 5 or more medications daily. With the average number of prescription items per year for any one person in England increasing (HSCIC, 2014). from 13 (in 2003) to 19 (in 2013). Globally it is estimated that between 30% and 50% of medications for long-term conditions are not taken as intended (WHO, 2003). And with an increasingly older population, the number of individuals with long-term conditions is increasing, by 2012 this number is suggested to have been 15 million (Department of Health, 2012).

Polypharmacy is related to multimorbidity, in which a patient has multiple diagnoses or conditions. A patient with multimorbidity may require multiple different medications, to manage their multiple conditions. Multiple medications in turn bring risks of inappropriate prescribing. Often, patients interact with different and separate parts of the health system in order to receive care for different conditions, adding to the complexity of ensuring appropriate prescribing.

There is a need to quantify and characterise the nature and extent of polypharmacy at a population level, to understand where there may be opportunities for improvement, both through reducing inappropriate prescribing and potentially in identifying novel benefits of medications for further study.


The aim of this project is to answer the following research questions:

  1. What is the prevalence of polypharmacy across NWL, against established definitions of polypharmacy?

  2. What are the patterns and trends in polypharmacy within the NWL population and sub populations, including by demographics, diagnoses, and patient and health system outcomes?

  3. What opportunities are there for using WSIC data to inform improvement in overprescribing and deprescribing of medications for patient benefit


At our October 2022 ARC NWL Collaborative Learning Event we ran a session on this work.

If you'd like to get involved in this work, hear more, or share your feedback on this session please contact d.lovett@imperial.ac.uk


Find out more about the work of the Information and Intelligence Theme