TYPE OF DRUGS USED

The nature of medication is usually described by presenting pharmacological substances that elderly persons are using most frequently (73,81-83). Another common way is to use specific drug classification systems in which upper levels are based on therapeutic categories of drugs. In terms of classifications, the most commonly used is the ATC classification, which is maintained by the WHO Collaborating Centre for Drug Statistics Methodology (84). Other classifications used are the BNF in British studies (85,86) and the AHFS in US studies (33,43,87). This chapter describes the changes which occurred over time in five most commonly used drug classes by elderly persons.

Cardiovascular drugs

For decades, cardiovascular drugs have remained the most commonly used category of drugs in elderly persons (35,63,83,88-90). Despite the fact that over the past decades new drug choices have been launched on the market for the treatment of cardiovascular diseases (CVDs), no remarkable change can be observed in the prevalence of the use of cardiovascular drugs over time.

A population-based Swedish study reported that one in every three (33%) of those aged 70 years and older used cardiovascular drugs at the beginning of the 1970s (13). The corresponding prevalence was 36%

among community-dwelling US elderly persons aged 63 years and older (91). Most studies on elderly persons from the 1980s reported prevalences between 40% and 80% for the use of cardiovascular drugs (79,92-95). Based on a Swedish study, in the late 1980s one in three (31%) persons aged 75 years and older used cardiovascular drugs (96).

Over this decade, hypertension and heart diseases were the most common conditions for which elderly persons used prescription drugs (97). The prevalence remained high (46–77%) in most studies conducted in the 1990s (43,53,79,80,98,99). However, some lower prevalences were also observed: 29–32% for Taiwanese (78), 37–47%

for Swedish (34,100), 38% for Italian (52) and 43% for English (55) elderly populations. During the 2000s, a prevalence of 71% was reported for community-dwelling Italian persons aged 65 years and older (101). In studies conducted in hospital and nursing home settings the prevalence has varied between 55% and 69% (40,49,70).

In treatment of various heart conditions, including cardiac arrhythmia and congestive heart failure, cardiac glycosides were frequently used (14–22%) in the 1970s and 1980s (29,58,73,94,100,102), but since then, the prevalence has decreased (4–14%) in most countries (13,40,67,80,103). Diuretics and β-blocking agents have maintained their position as common cardiovascular medication over decades.

Since the 1980s, the prevalence of the use of diuretics has varied between 11% and 35% (33,58,80,92,96,101,104). Correspondingly, prevalences between 7% and 28% have been reported for the use of β-blocking agents (13,58,85,94,100,105). Besides these traditional drugs, several new drugs have been adopted during the 1990s and 2000s as part of cardiovascular drug treatment of elderly persons. These

include ACE inhibitors, AT1 receptor antagonists, calcium channel blockers and lipid modifying agents (13,14,106). In the beginning of the 2000s, a study of community-dwelling Italians aged 65 years and older reported the prevalence of 32% for the use of ACE inhibitors and 12%

for AT1 receptor antagonists (101). The prevalence for the use of ACE inhibitors was 14% among a population-based Swedish study of those aged 77 years and older examined in 2002 (105). Slightly higher prevalences have been reported for the use of calcium channel blockers (23–51%) (49,101,106), whereas the proportion of persons using lipid modifying agent has varied between 12% and 27% during the 2000s (49,101,106,107).

Some studies have examined cardiovascular medication among those having polypharmacy or excessive polypharmacy. One Swedish study reported β-blockers (49%) and lipid-modifying agents (42%) to be the most prevalent cardiovascular drugs among those elderly persons who use five or more drugs (62). A US study examining those using nine or more drugs concomitantly reported a prevalence of 35%

for the use of diuretics and 24% for the use of ACE inhibitors in a nursing home setting (108).

Drugs for the nervous system

Over time a clearly increased prevalences can be observed for the use of drugs acting on the central nervous system (CNS) in elderly populations. In the 1970s and 1980s, these drugs were used by 14–25%

of those aged 65 years and older, based on studies of population-based samples and community-dwelling elderly populations (13,92,93). For similar populations, slightly higher prevalences (24–37%) were reported in the 1990s (34,35,55). With regard to psychotropic use, a Finnish study conducted in the late 1990s found a prevalence of 37%

for community-dwelling persons aged 75 years and older (109). In US nursing homes two-fifths (65%) were using psychotropics in the mid-1990s (99). An Italian study conducted in the 2000s reported a prevalence of 17% for the use of psychotropics among a community-dwelling elderly population (101). In the US, half (46–49%) of those aged 65 years and older used CNS drugs in studies conducted in community-dwelling (43) or home care settings (90). Of elderly hospital patients and nursing home residents, 23–57% used CNS drugs

in the 2000s (49,70,87). In Australian nursing homes 54% were using psychotropics (40).

The most commonly used psychotropics are hypnotics and sedatives. According to Swedish population-based studies, 10–26% of elderly persons were using these drugs during the 1980s and 1990s (13,14,96,100,110). Over the same time period, lower prevalences (4–9%) were reported for US and British elderly populations (31,92,104). In the 2000s, the prevalence was 11% in Italy (101) and 17% in Sweden (14).

In Swedish nursing homes up to 55% of residents were found to be using hypnotics and sedatives (111). Of demented Australians, every fourth (28%) was a user of these drugs (112). For the use of anxiolytics 5–14% prevalences have been reported in studies of population-based samples and community-dwelling elderly since the 1980s (31,92,96,100). The most common class of anxiolytics is benzodiazepines, which were used by 17% of Irish community-dwelling elderly persons in the mid-1990s (113). Almost half (46%) of nursing home residents using five or more drugs concomitantly used anxiolytics (62). Also antidepressants are widely used, showing prevalences between 3% and 12% for population-based and community-dwelling elderly populations since the 1980s (14,31,64,92,94).

Analgesics and antipyretics

Analgesics and antipyretics have been one of the most commonly used drug groups over the decades (29,68,74,83,89,108,114). Studies from the 1970s (13,63,91,102,115-117) and 1980s (31,88,92,94,104,118) have consistently reported prevalences of 16–32% for the use of analgesics among community-dwelling and institutionalized elderly populations.

Slightly higher prevalences (28–57%) were reported in the 1990s (13,14,64,78,103). The prevalences remained high (47–72%) in studies conducted in the 2000s (13,40,111). The highest prevalence was observed among US home care patients (90) and the lowest among Indian hospital patients (49). A recent Finnish study showed that 45%

of those aged 75 years and older were using analgesics daily or on an as-needed basis (119). When analysing only those using five or more drugs, 21% were users of analgesics and antipyretics (62). Almost half (46%) of the nursing home residents having nine or more drugs in use

used analgesics (108). Overall, these prevalence comparisons between different studies need to be interpreted with caution, because some studies had information only on prescribed analgesics, whereas others had also included analgesics purchased as over-the-counter drugs.

Paracetamol and NSAIDs are the most commonly used analgesics (54,63,114,119). According to the population-based Sloane study, paracetamol is used by every third (30–39%) and ASA by every fifth (17–23%) elderly Americans aged 65 years and older (67,68). A higher prevalence for the use of paracetamol (48%) was observed among elderly Finnish persons aged 75 years and older (119). For the use of NSAIDs, prevalences of 5–15% have been reported during the 1980s and 1990s (33,54,58,100,110). Thereafter, prevalences of 20–30% have been reported (119-121). In a Swedish population-based study, every fifth (21%) of those using five or more drugs concomitantly had NSAIDs or other antirheumatic products in their regimen (62). A US study of community-dwelling elderly reported separately a prevalence of 25% for the use of prescription NSAIDs and 41% for the use of over-the-counter NSAIDs (122). For the use of opioids, quite consistent prevalences (4–14%) have been reported over decades for population-based samples and community-dwelling elderly persons (14,58,80,100,110, 119,121,122).

Drugs for alimentary tract and metabolism

Among community-dwelling elderly persons, 18–34% have been reported to use drugs for alimentary tract and metabolism in studies conducted during the 1990s (34,52,80,95). The corresponding prevalences for hospital patients and nursing home residents have been remarkably higher (84–90%) (40,49). The most frequently used drugs belonging to this therapeutic category are drugs for gastrointestinal (GI) problems, vitamins, mineral supplements and drug for diabetes mellitus (74,80,90).

GI drugs are used by 10–31% of population-based samples and community-dwelling elderly persons, showing no remarkable change over decades (43,53,88,93,94,101,117). For similarly defined populations, the proportion of those using laxatives (4–17%) has remained at the same level since the 1970s (14,30,85,96,97,117,123). Of elderly hospital patients, 21–27% are using laxatives (54,102,118).

Among nursing homes patients the prevalences have been between 60–70% (40,103,111). Another commonly used group of GI drugs is antacids and proton pump inhibitors (PPIs), most studies reporting that 4–17% of elderly persons use some drugs for acid-related disorders (14,33,58,64,80,116). According to a Swedish study, 30% of those with polypharmacy (five or more drugs) use drugs for acid-related disorders (62). A recent study of Austrian hospital patients found that 37% of those aged 75 years and older had PPIs in use (107).

The estimates on the use of vitamins and mineral supplements are rather inconsistent. Based on the recent Sloane study, 58% of elderly Americans aged 65 years and older are using some vitamins (68).

Italian studies from the 2000s revealed remarkable differences in the prevalence of vitamin use between community-dwelling (5%) (101) and hospitalized (45%) (121) elderly persons aged 65 years and older.

A recent study of Finnish nursing homes reported that 33% of the residents were receiving vitamin D supplementation and 28% calcium supplementation (124).

Blood and blood-forming organs

The use of drugs for blood and blood-forming organs has become common in the 1990s. Over this period the highest prevalences (23–

39%) for the use of these drugs were observed in Nordic studies of community-dwelling elderly persons (34,53,80). The corresponding prevalences were reported to be 6% for Italian (52) and 8% for elderly US populations (43). Studies conducted in US nursing homes found every fifth (18%) resident to be using drugs for blood and blood forming organs (99). Over a ten-year period from 1992 to 2002, the prevalence increased from 3% to 43% among those aged 77 years and older (14). Other studies conducted in the 2000s have found a prevalence of 46% for Australian nursing home residents (40) and 53%

for hospitalized elderly persons in India (49).

The observed increase in the use of drugs for blood and blood-forming organs during the past two decades is mostly due to increased use of antithrombotic agents as part of elderly persons’ medication.

Before the 1990s, the use of antithrombotics was rare, as only a couple of percent of elderly persons were using these drugs (13,79,92).

Thereafter, most studies have reported remarkably higher percentages

(16–43%) for the use of antithrombotics (13,14,40,103). Based on a recent study, antithrombotics were used by half (52%) of those having five or more drugs in use concomitantly (62).