High Polypharmacy, Drug-Drug Interaction Rates Among Elderly PLWHIV

The high rates of polypharmacy and consequent potential for drug-drug interaction requires attention when prescribing treatments for elderly people living with HIV (PLWHIV), according to a study published in Open Forum Infectious Diseases.

The advent of antiretroviral therapies (ART) have allowed many cases of HIV to transition from a potentially fatal infection to a chronic disease. Therefore, PLWHIV are attaining older age and thus developing common age-related conditions. Subsequently, elderly PLWHIV are at a significantly higher likelihood to receive polypharmacy, and thus the potential for drug-drug interactions or potentially inappropriate medications.

In this multicenter prospective cohort study, which has been continuously enrolling PLWHIV since 1988, researchers analyzed survey responses from PLWHIV (N=996) who were asked to list all of their current medications, the respective dosage of each, and the date and time of the last drug intake. Comedications were classified by anatomic therapeutic chemical classification. Potentially inappropriate medications were assessed using the most recent version of the classical Beers criteria.  Researchers focused on 2 therapeutic classes: cardiovascular and central nervous system (CNS).

The drugs reported included ARTs, other prescription medications, and over-the-counter remedies. Of note, integrase stand transfer inhibitors (INSTI)-containing regimens accounted for roughly 50% of all ART prescriptions.

Of the PLWHIV included, 88% were aged <65 years (n=874) and 12% were aged ≥65 years (n=122). Polypharmacy was more prevalent in older PLWHIV compared with the younger group (44% vs 12%). Cardiovascular class drugs were most utilized in the older group (73% of responses included ≥1 cardiovascular drug), whereas CNS drugs were more commonly reported among the younger group, where 26% of responses included ≥1 CNS drug. Thirty-eight elderly patients (31%) had a least 1 potentially inappropriate medication, most commonly benzodiazepines and hypnotics. A total of 767 forms indicated the use of 1 cardiovascular or CNS drug among 500 participants; 23%, 28%, and 2% were flagged as yellow, amber and red for potentiality for drug-drug interactions, respectively. However, results did not indicate a statistical difference in the use of these medications between the age groups.

Study limitations included its reliance on only 2 compounds to assess potential drug-drug interaction that may have occurred with other drug classes. The researchers also did not assess interactions between non-HIV comedications, which may have led to an underestimation in the actual number of potential drug-drug interaction.

“Although the use of unboosted INSTIs is growing, one-fourth of elderly [PLWHIV] had complex ARTs acting as perpetrator of [drug-drug interaction],” the researchers concluded. “Thus with the aging HIV population, education on geriatric medicine principles and periodic review of medicines is warranted to limit the risk of inappropriate prescribing in this vulnerable population. Clinicians should maintain a proactive approach for the recognition and management of potential [drug-drug interactions], as well as for other prescribing issues traditionally encountered in geriatric medicine.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Courlet P, Livio F, Guidi M, et al. Polypharmacy, drug-drug interactions, and inappropriate drugs: new challenges in the aging population with HIV [published online December 21, 2019]. Open Forum Infect Dis. doi:10.1093/ofid/ofz531