Older adults who underuse essential medications increase their risk of being hospitalized or dying, according to the results of a newly published study in the British Journal of Clinical Pharmacology.

Maarten Wauters, a Ph.D. student at Ghent University in Belgium, and his colleagues base their conclusions on their 18-month study of 503 people who were aged at least 80 years. Excluded from the study were those living in nursing homes, those with known dementia and those receiving palliative care.

The researchers found that 58% of the study participants were taking five or more medications for chronic conditions every day. Few of the older adults were taking medications appropriately, with 67% underusing their drugs and 56% misusing them (some overlap exists between these groups). Just 17% of the study population was not affected by any kind of underuse or misuse.

Underuse was associated with 39% and 26% increased risks of mortality and hospitalization, respectively, per underused medication. The researchers were unclear about associations related to misuse.

“Taking too many medications or unsafe medications are known to cause adverse health outcomes; however, we have shown that not taking essential, beneficial medications is more frequent and can be more strongly associated with negative outcomes,” Wauters said.