Women and the Elderly Incur a Higher Risk of Adverse Drug Interactions

Women and elderly people are negatively affected by the occurrence of drug-drug interactions (DDI) that lead to adverse drug reactions (ADR), according to a study published in NPJ Digital Medicine.

In this large-scale longitudinal study, researchers assessed the electronic health records (EHRs) of individuals living in the city of Blumenau, Brazil (pop. 338,876) over the course of 18 months using a city-wide Health Information System (HIS) with prescription and dispensation information for its entire population. All dispensed drugs analyzed were available via medical prescription only and were provided free of charge. All EHR data were randomized and included demographic variables including gender, age, neighborhood, marital status, and education level. In total, the researchers analyzed 122 unique drugs, evaluating them under the assumption that all dispensed drugs were also administered.

Through all of 2014 and the first six months of 2015, the HIS registered 1,573,678 distinct drug interval administrations that were dispensed to 132,722 people, or roughly 39% of the city’s population. The study population was comprised of 41.5% female, 58.5% male, respectively. Almost 79% of the study population were dispensed two or more distinct drugs over the study period, and only this subset could have potential DDIs.

Dangerous Drug Pairing

The findings uncovered 181 distinct drug pairs known to interact, and these pairs were dispensed concomitantly to 12% of the patients in the city’s HIS. Moreover, the study found that 4% of the patients were dispensed drug pairs that are likely to result in major ADRs, with the cost implications of these reactions estimated to be much larger than previously reported. Additionally, a large-scale analysis showed that women have a 60% increased risk of DDI juxtaposed to men, with that increase rising to 90% when considering only DDIs known to lead to major ADRs. Furthermore, DDI risk increases substantially with age with patients aged 70–79 years found to have a 34% risk of DDI when they are dispensed two or more drugs concomitantly.

“Our large-scale epidemiological analysis demonstrates that an integrated data- and network-science approach to public health can uncover biases in the DDI phenomenon as well as yield tools capable of issuing accurate DDI prediction per patient,” the study authors wrote. “Both outcomes contribute to preventing ADR from DDI and thus may lead to a significant positive impact on the quality of life of patients and finances of public-health systems.”

The authors added that, moreover, “the gender and age risks of DDI we discovered, should inform physicians and other health professionals anywhere that such factors are important in the drug management of their patients. We expect the results to increase awareness of those risks we uncovered.”