Commentary by Elizabeth D. Kantor, PhD; Alan Garber, MD, PhD; and John Meigs, MD
“When we look at these results, we might first think that this is attributable to the aging of the U.S. population. However, when we adjust for the changing age structure of the U.S. population, we found that these trends persisted, suggesting that there are factors other than age that are driving the observed increase prescription drug use,” explained Elizabeth D. Kantor, PhD.
Dr. Kantor and colleagues evaluated trends in prescription drug use among 37,959 adults (ages ≥ 20 years) participating in NHANES. Seven NHANES cycles were included (1999-2000 to 2011-2012), and the sample size per cycle ranged from 4,861 to 6,212. Within each NHANES cycle, use of prescription drugs in the prior 30 days was assessed overall and by drug class.
The prevalence of prescription drug use increased from 51% in 1999-2000 to 59% in 2011-2012, while the prevalence of using of ≥5 prescription drugs increased from 8% to 15%.
Notably, several of the top 10 most commonly used drugs in 2011-2012 were medications used to treat factors associated with the cardiometabolic syndrome—including hypertension, diabetes, and dyslipidemia—or obesity.
“These findings are not unexpected,” commented Alan Garber, MD, PhD, Professor of Medicine, Biochemistry, Molecular and Cellular Biology at Baylor College of Medicine, Houston, Texas. “When you define who is at risk for cardiovascular disease, you define a population that has multiple cardiovascular risk factors, all of which require independent treatment with one or more medications. It is no surprise that patients are taking 5 or more drugs,” said Dr. Garber, who also is President of the American College of Endocrinology.
“Obesity is a significant risk factor for multiple health conditions, including diabetes and heart disease, so it’s not a surprise that there has been a major increase in the use of medications that treat these conditions,” commented John Meigs, MD, president-elect of the American Academy of Family Physicians and a family physician in Centreville, Alabama. “When we care for patients with diabetes, it is essential to help them manage their blood sugars as well as treat other cardiac risk factors. At the same time, we must be aware of the risks of polypharmacy and avoid it whenever possible,” Dr. Meigs said.
Increases in Select Diabetes Medications Found
Use of diabetes medications increased from 4.6% to 8.2% (P-trend <0.001) during the study period, with a sharp rise found for use of insulin and biguanides. Specifically, use of metformin increased significantly (from 2.0% to 4.9%; P-trend <0.001) and was the fifth most common medication used overall. Use of thiazolidinediones increased before 2003-2004 and then decreased thereafter, with the overall use of these agents remaining unchanged during the study period.
The increased prevalence of insulin use “is partly a reflection of our success in reducing cardiovascular events. But as these rates of cardiac events have declined, people survive longer and accrue more illnesses. In the case of diabetes, patients survive longer and eventually oral agents are unable to keep their glucose levels under control, and they need injectable insulin,” Dr. Garber said.
Top 10 Most Commonly Prescribed Medications
Simvastatin was the most commonly used drug in 2011-2012 (7.9%), increasing from 2.0% in 1999-2000. The remaining top 10 drugs included lisinopril, levothyroxine, metoprolol, metformin, hydrochlorothiazide, omeprazole, amlodipine, atorvastatin, and albuterol. With the exception of atorvastatin, all of these medications increased in use over the study period.
Nearly 40% of Elderly Use 5 or More Medications
The increase in use of 5 or more medications “was particularly notable among participants age 65 and older where we observed polypharmacy to increase from 24% to 39% in 2012,” said Dr. Kantor.
When examining whether trends for particular drug classes varied over the period, study authors found that the greatest increase in prescription drug use occurred early in 2000s, “which I think is interesting as we think of what factors may or may not be driving the observed increase in prescription drug use,” Dr. Kantor said.
Clinical Implications of Polypharmacy
“I think there is misplaced emphasis on the number of medications that a patient is taking. It is not a negative pronouncement, but means that patients are being treated for the illnesses that they have and are likely to survive longer with those illnesses than if they were untreated,” Dr. Garber said. He added that it is important for physicians and pharmacists to be aware of the high rate of polypharmacy in order to better counsel patients about drug-drug interaction.
“Elderly patients on 5 or more medications are more likely to be hospitalized, experience falls, have cognitive impairment, and have a higher mortality rate than the general population,” Dr. Meigs said. “Patients who see multiple healthcare providers are more likely to experience polypharmacy, as each provider may prescribe multiple medications without considering what else the patient is taking,” Dr. Meigs continued.
“A family physician is essential to help avoid and address polypharmacy,” Dr. Meigs noted. “Family physicians are trained in every organ system, so we can help determine which medications are essential, which may interact with each other, and, which are potentially harmful. We also can work with patients on lifestyle changes to treat their health conditions, which in the long run can result in decreasing the dosage or discontinuing certain medications,” Dr. Meigs concluded.
November 11, 2015
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):1818-1830
Journal of the American Medical Association. News Release: Increase Seen in Prescription Drug Use in U.S. Accessed November 4, 2015. Available at: http://media.jamanetwork.com/news-item/increase-seen-in-prescription-drug-use-in-u-s/#