Findings

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Prescription medications, over-the-counter  (OTC) products, and natural and alternative medicines are widely used in Canada, especially by seniors. But while medications play an important role in health care and disease management, their use is not without risk.¹

Multiple medication use (prescription or OTC) is a common concern in relation to seniors’ health.^2-5 In 2005, pharmacists dispensed an average of 35 prescriptions per person aged 60 to 79, and 74 prescriptions per person aged 80 or older, compared with an overall average of 14 prescriptions per Canadian.⁶ People who take several medications at once are more likely to have adverse drug reactions; seniors are particularly vulnerable because of co-morbidity and physiological changes that come with age.^3, 4, 7-9

There is a need in Canada for information about the number of seniors who use medications and those who have an elevated risk of drug-related adverse events from multiple medication use. The current study addresses these issues with data from nationally representative samples of seniors living in private households and in long-term health care institutions (see The data). In addition, the study reveals the most commonly reported types of medications and health-related factors associated with seniors’ medication use.

Medication use

Nearly all residents of health care institutions were current medication users: 97% had taken some form of medication in the past two days (Table 1). As well, a large majority (76%) of seniors living in private households had done so.

Among the household population, women were more likely than men to have taken medications in the past two days, and seniors aged 75 to 84 were more likely to have done so than those aged 65 to 74. Differences based on educational attainment or the use of proxy reporters were not evident.

For seniors in institutions, the likelihood of taking medication did not differ by sex, age group, educational attainment, or proxy response.

Multiple medication use

Multiple medication use (taking five or more different drugs in the past two days) was reported for 53% of seniors in health care institutions and 13% of those in private households (Table 1, Figure 1). The likelihood of multiple medication use did not differ by sex, regardless of whether seniors lived in private households or in institutions.

Only among household residents was there a difference by age group—those aged 75 to 84 were more likely to be multiple medication users than were younger seniors (16 % compared with 11%). For institutionalized seniors, those who relied on proxy reporters were significantly less likely to report multiple medication use (45%) than were those who responded on their own behalf (65%).

Medication use, including the use of multiple medications, tended to be positively associated with indicators of ill health. For example, seniors who assessed their general health as poor were more likely to have used five or more different medications in the past two days than were those in better health (Table 2). As well, the number of chronic conditions reported, the presence of chronic pain, and having specific chronic conditions were associated with medication use (Table 2). Even when sex, age, education, and proxy reporter were taken into account, the presence of chronic pain and a greater number of chronic conditions were each independently associated with higher odds of using multiple medications in the fully controlled model (Table 3).

A notable exception to the positive associations between chronic conditions and medication use emerged for institutionalized seniors who had Alzheimer’s disease or other dementia (Table 2). They were less likely to be multiple medication users than were institutionalized seniors without this condition: 40% compared with 62%. This is the reverse of the association for seniors in households, among whom a higher proportion with Alzheimer’s disease reported using multiple medications (34%), compared with those without this condition (13%). Among institutionalized seniors, the average age of those with and without Alzheimer’s disease did not differ, although those with Alzheimer’s disease had, on average, more chronic conditions (4.3 versus 3.4). Despite the tendency toward a greater number of chronic conditions, institutionalized seniors with Alzheimer’s disease were less likely have chronic pain (28% versus 44%), less likely to be on pain medication (44% versus 58%), and received, on average, fewer medications overall than did institutionalized seniors without Alzheimer’s disease or other dementia (4.4 medications versus 5.9).

Types of medications

The medications reported most commonly by seniors were those that act on the nervous system, the alimentary tract and metabolism, and the cardiovascular system (Table 4).

Almost four out of every five (78%) seniors in institutions and 37% of those in households took medications for the nervous system. Of these medications, analgesics were the most common, followed by psycholeptics, which include antipsychotics, anxiolytics, hypnotics and sedatives.

Medications for the alimentary tract and metabolism were used by 71% of seniors in institutions and 23% of those in households. Of these medications, laxatives were commonly reported for seniors in institutions (62%), followed by antacids, and drugs for the treatment of peptic ulcers and flatulence (34%). For seniors in households, peptic ulcer and flatulence medications were most common (40%), followed by drugs for diabetes (34%); laxatives were rarely reported (9%).

More than half (55%) of seniors in institutions and 44% of those in households reported taking cardiovascular medications. This group of medications is composed of diuretics, cardiac therapy drugs, antihypertensives, calcium channel blockers, and beta-blocking agents. Diuretics were most commonly reported for seniors in institutions, and antihypertensives were prominent for seniors in private households.

Conclusion

This is the first nationwide, population-based study to provide benchmarks of medication and multiple medication use among all Canadian seniors, covering not only private households, but also long-term health care institutions. The stringent collection process for medication information minimizes the potential for recall bias: household residents were asked to read the names of their medications to the interviewer; staff members provided the information for institutionalized respondents. This approach has an advantage over some administrative data in cases when discrepancies emerge between medications that are prescribed and those that are actually used.

Medication use by seniors is common—almost all seniors in institutions and over three-quarters of those in households reported using at least one medication in the past two days. Concurrent use of five or more medications was reported by 53% of seniors in institutions and 13% of those in households. This amounts to over a half million seniors taking multiple medications: approximately 94,000 in institutions and 445,000 in households.

Although medication use was generally associated with morbidity, this study identified unique circumstances for institutionalized seniors with Alzheimer’s disease or other dementia. They tended to have more chronic conditions than institutionalized seniors without Alzheimer’s disease, but were less likely to report pain, to have taken pain medications or to be multiple medication users. These findings are consistent with earlier studies that suggest higher levels of cognitive impairment are associated with undetected pain and subsequent under-treatment.^20-23

Finally, people take several medications at once for many reasons including comorbidity, multiple prescribing physicians, inappropriate prescribing, access to different pharmacies, as well as self-medication with OTC and alternative products.^{4, 5, 24, 25} Regardless of the reason, those who take multiple medications have an elevated risk of adverse events.