Polypharmacy, or using different medications at the same time, can increase the risk of dangerous side effects. A recent study measured how common polypharmacy is among older adults in the United Kingdom.
Combining prescription medications can potentially cause serious side effects. Known as polypharmacy, using many different medications at one time can be dangerous as they can interact with each other in various complex ways. Polypharmacy may be becoming more common. A group of researchers in the United Kingdom sought to determine just how common polypharmacy is in older adults, and if it increased with age. The results of their study were recently published in the journal BMC Geriatrics.
The MRC National Survey for Health and Development
The researchers conducted their study on participants in the MRC National Survey for Health and Development. This study has tracked more than 5,000 individuals who were born in the same week in 1946 in England, Scotland & Wales. Currently, almost 2,700 participants are alive and have a known address in mainland Britain. The researchers sent nurses to carry out home interviews with more than 2,000 69-year-old participants, collecting information on prescribed medications that were currently being used. They compared this information with data collected five years previously.
Polypharmacy was common in older adults
The researchers found that the study participants were taking an average of two medications each, with 80% of the 69-year-old study participants taking at least one medication and 60% taking two or more. Almost 23% of participants were taking five or more medications. The most common type of medications were those to treat cardiovascular disorders, which were being taken by more than half of the study participants. A third of the participants were taking multiple cardiovascular medications.
The study participants were, on average, taking more medications than they had five years earlier. The number of drug-free participants dropped by almost 9% over that period, and the number of participants taking between one and four medications increased by 6%. The number of participants taking five or more medications increased, although by a smaller amount. The number of participants receiving multiple different medications to treat cardiovascular conditions also increased with age.
Polypharmacy was more common in those with lower levels of education
Not surprisingly, participants with more diseases, or more severe diseases, were more likely to be taking more medications. Participants with less education were also more likely to be taking more medications. For example, participants who hadn’t graduated from secondary schools were almost twice as likely to be taking at least nine medications compared to those who had completed secondary school. They were five times more likely to be taking at least nine medications compared to those with post-secondary qualifications.
Participants with less education also tended to have greater disease burdens. However, the researchers found that this difference was not sufficient to account for the increased rate of polypharmacy in this group.
There were no overall differences between the genders for polypharmacy in general, but there was a gender difference for medications for cardiovascular disease: men were twice as likely as women to be taking five or more drugs for heart disease.
Education and gender differences should be investigated in future polypharmacy research
The researchers acknowledged several weaknesses of their study. Notably, they relied on participants to accurately report their medication usage and which diseases they were suffering from. They also did not collect information on which doctors that the participants were attending. Since some doctors may be more likely to prescribe multiple medications than others, this may have been a major contributor to variation in how many medications patients were receiving.
There is a need to investigate why patients with lower levels of education are receiving more medications. This difference could not be accounted for by increased disease burden in these patients. Likewise, men were more likely to be taking multiple medications for cardiovascular conditions. Both these patient groups would potentially be at greater risk of experiencing adverse side effects due to drug-to-drug interactions. It is important for more research to investigate these issues.
Written by Bryan Hughes, PhD
Reference: Rawle, M. J., Richards, M., Davis, D. &Kuh, D. The prevalence and determinants of polypharmacy at age 69: a British birth cohort study. BMC Geriatrics18, 118 (2018)