US Adults Using More Drugs, and More Use Multiple Drugs

Use of prescription drugs is rising, and the number of US adults who take multiple drugs is rising even faster, according to a study that today appeared in JAMA.

The study led by Elizabeth Kantor, PhD, MPH, formerly of Harvard’s T.H. Chan School of Public Health, sought to examine prescription drug use across the population, rather than just increases of individual prescriptions.

Data from the National Health and Nutrition Examination Survey (NHANES) looked at prescription drug use among 37,959 US adults outside institutions during 2 time frames, from 1999-2000 and from 2011-2012. Overall, the number of US adults using prescription drugs rose from 51% to 59% across the 2 periods.

What’s more, there was a sharp jump in the percentage of adults taking at least 5 prescriptions: 8.2% in the 1999-2000 time frame, and 15% in the 2011-2012 period.

Among the 18 drugs classes used by at least 2.5% of the population during the study period, 11 saw an uptick in use, including agents for high cholesterol, antidepressants, prescription proton-pump inhibitors—which treat gastric acid—and muscle relaxants.

Antidiabetic agents were among the drug classes that saw higher use; these rise from 4.6% of the population to 8.2%. Specifically, increases were seen for biguanides, insulin, and sulfonylureas.

Prescription drug use increased significantly among persons aged 40 to 64 years (from 57% to 65%) and among those age 65 and older (84% to 90%), but not among those age 20 to 39 years (32% to 35%).

Although significant increases in the percentage of those using at least 5 prescriptions took place in all racial groups, there were differences among those taking any prescription at all. The share of whites taking any prescription drug rose from 55% to 66%, and non-Hispanic black rose 42% to 52%. There was not as large an increase among Mexican Americans (30% to 33%).

The single most commonly prescribed drug in 2011-2012 was simvastatin (7.9%), which rose from 2.0% in 1999-2000. Other drugs in the top 10 were Lisinopril, levothyroxine, metoprolol, metformin, hydrochlorothiazide, omeprazole, amlodipine, atorvastatin, and albuterol. All increased during the study period except atorvastatin.

Reference

Kantor ED, Rehm CD, Haas JS, Chan AT, Giovannucci EL. Trends in prescription drug use among adults in the United States from 1999-2012. JAMA. 2015;314(17):1818-1831.