The weighted distribution of demographic and health characteristics in the NSHAP sample correspond closely to those of the population and other national samples.16
Of the 3005 respondents, 2976 (99%) completed the medication log.
reports the prevalence of medication use by type, both overall and within sociodemographic and health subgroups. During 2005 to 2006, 91% (95% CI, 90.0%–92.5%) of older adults, corresponding to 50.5 million adults aged 57 to 85 years, regularly used at least 1 medication. Among all medication types, prescription medication use was the most prevalent, used by 81% (95% CI, 79.4%–83.5%), or 44.9 million older adults. Nearly one-half of older adults regularly used at least 1 over-the-counter medication or dietary supplement. The prevalence of prescription medication use was highest among the oldest age group; 89.7% (95% CI, 87.4%–92.1%) of persons aged 75 to 85 years used at least 1 prescription medication, compared with 74.3% (95% CI, 69.9%–78.7%) of those aged 57 through 64 years. Women were more likely to use prescription medications (86.0%; 95% CI, 83.8%–88.2%) than men (76.6%; 95% CI, 73.1%–80.1%). While the prevalence of dietary supplement use was greater in women (55.4%; 95% CI, 51.7%–59.2%) compared with men (43.1%; 95% CI, 39.5%–46.8%), the prevalence of over-the counter medication use was similar among women (41.9%; 95% CI, 38.7%–45.1%) and men (42.6%; 95% CI, 39.5%–45.7%).
depicts the likelihood of no regular medication use by individuals’ sociodemographic and health characteristics. As expected, medication use was more likely among those with poorer self-reported health and more comorbid conditions. In addition, medication use was more likely among nonpoor respondents and those with greater formal education.
Sociodemographic and Health-Related Factors Associated With No Regular Medication Use Among Older Adults in the United States
Commonly Used Prescription and Nonprescription Medications
The most commonly used prescription or over-the-counter medications, either as single or multi component products, were cardiovascular agents, including antihyperlipidemics and anticoagulants such as aspirin, hydrochlorothiazide, atorvastatin, lisinopril, metoprolol, simvastatin, atenolol, amlodipine, furosemide, ezetimibe, valsartan, warfarin, and clopidogrel (). Across all age groups, the prevalence of use of the statins atorvastatin and simvastatin was higher among men compared with women.
Weighted Prevalence Estimates of the Most Commonly Used Prescription and Over-the-counter (OTC) Medications by Age and Gendera
The most commonly used dietary supplements were nutritional products, including multivitamins and individual vitamins or minerals (). Alternative therapies intended for use in improving cardiovascular health (eg, omega-3 fatty acids, garlic, coenzyme Q) and other age-related chronic conditions (eg, “eye vitamins” for macular degeneration, glucosamine-chondroitin, saw palmetto) were also widely used. The prevalence of dietary supplement use tended to be lowest in the youngest age group. Across all age groups, calcium, vitamin D, and glucosamine-chondroitin supplements were more commonly used among women than men, while niacin was more commonly used among men.
Weighted Prevalence Estimates of the Most Commonly Used Dietary Supplements by Age and Gendera
Most Commonly Reported Medical Conditions and Comorbidity
Cardiovascular disease was the most commonly reported medical condition, and its prevalence was similar among men and women (). Women reported more comorbid conditions compared with men aged 57 through 64 years. For example, 37% (95% CI, 33.6%–40.9%) of men reported no comorbid conditions compared with 25% (95% CI, 20.6%–29.6%) of women in this age group. In addition, thyroid problems, arthritis, and asthma were more prevalent in women than in men across all age groups. A total of 26 respondents reported that a physician had told them that they had Alzheimer disease or some other form of dementia, but the interviewers considered them able to participate in the survey.
Weighted Prevalence Estimates of the Most Commonly Reported Medical Conditions and Comorbidity By Age and Gendera
Concurrent Use of Medications
Overall, more than half of older adults used 5 or more prescription medications, over-the-counter medications, or dietary supplements. depicts this practice, stratified by respondents’ age and gender. For prescription medications, 29% (95% CI, 26.6%–30.6%) of all respondents used more than 5 medications. The prevalence of the use of 5 or more prescription medications increased steadily with age for both men and women and was overall significantly higher among women (P=.003), though this gender difference was observed only among the youngest 2 age groups. Only 3 respondents reported the use of 5 or more over-the-counter medications. However, nearly 1 in 8 older adults regularly used 5 or more dietary supplements.
Weighted Prevalence Estimates of Prescription Medication, Over-the-counter Medication, and Dietary Supplement Use by Age and Gender
illustrates the prevalence of concurrent use of nonprescription therapies (those available without a prescription, regardless of whether a physician had prescribed them) among users of prescription medications by age and gender. Overall, 68% (95% CI, 64.8%–71.1%) of older adults using prescription medications were concurrently using over-the-counter medications, dietary supplements, or both. Across all age groups, men and women were equally likely to use prescription and nonprescription medications concurrently. However, men were more likely to concurrently use over-the-counter medications, whereas women were more likely to concurrently use dietary supplements. Sixty percent (95% CI, 54.0%–66.8%) of women in the oldest age group used prescription medications in combination with dietary supplements. Among prescription medication users, more women than men concurrently used nutritional products, alternative therapies, or both.
Weighted Prevalence Estimates of Concurrent Use of Nonprescription Medications (Over-the-counter Medications and/or Dietary Supplements) Among Prescription Medication Users by Age and Gender
Potential Major Drug-Drug Interactions
A total of 46 potential drug-drug interactions were identified using Micromedex (). Among these, 11 were classified as potentially of major severity, 28 were classified as potentially of moderate severity, and 7 were classified as potentially of minor severity. Not one absolutely contraindicated drug-drug interaction was identified in the entire sample. Overall, 1 in 25 older adults (approximately 2.2 million) were at risk for a major potential drug-drug interaction. The rate of any major medication interaction increased with age for both men and women but was higher among men compared with women across all age groups. Prevalence of a major interaction was significantly greater among men than among women (P = .01). More than half of these major interactions involved the use of nonprescription therapies. In addition, nearly half involved the use of anticoagulants (eg, warfarin) or antiplatelet agents (eg, aspirin). Across all age groups, the concurrent use of aspirin and warfarin was significantly more common in men than women (P<.001). In addition, the concurrent use of niacin and atorvastatin was also significantly more common in men than in women (P=.03).
Potential Major Medication Interactions by Age and Gendera