Older adults receiving outpatient services have an increased risk of using potentially inappropriate medications, according to an international study released Wednesday. Using these medications also has become more common in the past two decades, researchers say. 

The meta-analysis, which was published in JAMA Network Open, reviewed 94 reports covering 371.2 million people over age 60 or over age 65 from 17 countries. Overall, the prevalence of potentially inappropriate medication use was 36.7%. People in Africa had the highest prevalence of medications that weren’t appropriate for them. The pooled prevalence of potentially inappropriate medication use in North America was 29%.

Potentially inappropriate medicines are linked to higher adverse drug events and visits to the emergency room. People on them have a lower quality of life as well, the report said. The medicines also raise outpatient drug fees and the number of outpatient visits, and boost outpatient medical resources use while upping the risk for hospitalization. 

Over the course of the past decade, using potentially inappropriate medications has increased by more than 40% worldwide. This comes as the older population has increased in the past 20 years, and they’re more prone to multiple diseases.

The authors say their findings show the need for healthcare reforms on drug safety globally.

The news comes as a report, also released Wednesday, in the Journal of the American Geriatrics Society found that more than one-third of older adults don’t take their medications the way they’re instructed. That team looked at medication adherence in 5,164 participants over the age of 65.

In those not taking medication as directed, 77.4% said it was because of poor memory, while 5.4% said they didn’t follow the rules because they ran out of the medication. And 1.2% said they didn’t stick with instructions because they couldn’t afford their meds. In those over 75 years old, 37.2% didn’t adhere to medication instructions.