Taking five or more prescription medications increases the risk of hospitalization and death in older adults infected with HIV and comparable adults without HIV. The findings of this Yale-led study highlight the potential risks of prescribing additional drugs to patients with multiple medical conditions.

The research was published online in the journal AIDS.

The use of multiple medications is known as polypharmacy, a common concern due to clearly established increased rates of drug interactions and use of inappropriate medications. However, few studies in the general population, and no prior study among those with HIV infection, have examined actual health outcomes associated with polypharmacy.

Using patient data from the Veterans Aging Cohort Study, lead author Amy Justice, MD, and colleagues analyzed outcomes for HIV-positive and uninfected individuals who received at least one prescription from the VA in 2009. Because patients with HIV must take at least three antiretroviral (ARV) drugs to treat HIV infection, the researchers focused on non-ARV prescriptions. They followed the patients, who were typically over age 50 years, for an average of 6 years.

The research team found that non-ARV polypharmacy was common among aging adults with and without HIV infection. What wasn’t clear initially was whether patients were on more medications because they were sicker, or whether being on more medications made them sicker. After adjusting for the severity of the patients’ illnesses, the researchers found that polypharmacy continued to be associated with hospitalization and death. Notably, the more medications prescribed, the greater the risks for both groups of patients, the researchers said.

“The point of this study is that we need to start looking at medications among people with multiple conditions very carefully,” said Justice. “Clearly HIV must be treated. But how many other medications a patient should be taking remains an open question.” Given the similar results for individuals without HIV, the study may also be important for future research on polypharmacy in all aging adults, Justice said.

While the study did not focus on the reasons behind the increased risks, factors, such as toxicity, side effects, and drug interactions, are likely causes, the researchers noted.