**3. Determinants of non-adherence**

**2. Medical adherence taxonomy**

28 Gerontology

difficult to draw conclusions.

first and the last dose of medicine [19–21].

behavior that involves three critical steps (**Figure 2**).

science, pharmacometrics and health economics [19].

practice [22].

adherence to medication [22].

"Drugs don't work in patients who don't take them" is the often-cited statement of Surgeon General of the United States C. Everett Koop (1985). Non-adherence is the major problem for pharmacotherapy in ambulatory patients. It is more prevalent than would be expected. It is highly associated with increased morbidity and mortality, and is an aspect that until recently was neglected. Despite its importance and all the efforts that have been made to understand it, non-adherence is still misunderstood. This behavior, in addition to the direct effects on the patient, since it compromises the preservation and the quality of her/his life, also has economic consequences. Therefore, in recent years, therapeutic adherence has been extensively studied from pharmacological, behavioral, economical perspectives [17]. Despite all the studies, the lack of uniformity in the methods of analysis and the absence of a universal taxonomy/ terminology are a major obstacle when making/analyzing systematic reviews, as it makes it

*Compliance, adherence, concordance* and *persistence* are the four widely used terms that have been used interchangeably. *Adherence* and *compliance*, the mostly used terms have different connotations in the patient's attitude regarding medication. *Compliance* comes from the Latin word *complire*, meaning to fulfil a promise/to complete an action, implying that the patient has a passive role on the process. *Adherence* derives from the Latin word *adhaerere,* which means remain constant, keep close, having the patient agreed with the prescription [15, 18, 19]. Of the other two terms, *Concordance* implies that the patient and the professional healthcare came to an agreement about the treatment that the patient should follow, acknowledging that they may have different points of view, while *persistence* relates to the time interval between the

Given this heterogeneity, it was necessary to obtain a consensus on the terminology and taxonomy in the field of non-adherence. The ABC project (Ascertaining Barriers to Compliance) was created under the seventh Framework Program, and the main objective was to provide consensus taxonomy and terminology in non-adherence medication and to provide concise and adequate definitions that could serve the needs of both clinical research and medical

*Medication adherence* is defined as an active, cooperative and voluntary participation of the patient in following recommendations from a healthcare provider. This is a multifactorial

*Management of adherence* has a main purpose to increase the benefit to the patient, and minimize the risk of harm, caused by the medication. It encompasses healthcare systems, providers, patients and their family/friend's networks, and serves to monitor and support patient's

*Adherence-related sciences* include all the disciplines that study the causes and consequences of non-adherence, including medicine, nursing, sociology, biostatistics, pharmacy, behavioral Non-adherence to therapy is a public health problem in general, with a special focus on the elderly population. Non-adherence causes the patient outcome to be compromised, resulting in decreased effective disease control, increased risk of hospitalization and increased morbidity and mortality [23].

To improve the adherence, we must first understand the causes, predictors and determinants responsible for non-adherence. Many of them have been described so far [24]. According to WHO, there are five large sets of factors by which people are non-adherent (**Figure 3**) [25]:

the individual based on their beliefs about the consequences of adherence to therapy, when the patients recognize that they have a responsibility to their health and that their behaviour may

Adherence to Medication in Older Adults as a Way to Improve Health Outcomes and Reduce…

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bring benefits, which improves adherence [15].

**Figure 3.** Predictors of non-adherence to medication, modified from WHO [25].


The socioeconomic status is correlated with adherence to therapy. Of these factors, the professional situation, social support, housing conditions, distance to treatment, transportation and medication prices as well as social inequalities are the utmost importance. The existence of support provided either by the family or by friends has a very positive influence on adherence. The lack of involvement of family and friends leads to a state of social isolation, which is one of the determinants of non-adherence [26]. The professional situation is also important, since people with economic difficulties must set priorities in budget management, with food and housing being the first, often leaving the medication to second option [22].

The relationship between health professionals and patients is extremely important in adherence, since they play a critical role of technical and psychosocial support, giving the individual the basic skills to adhere to medication, developing beliefs about his/her ability to deliver on medications and on the benefits of therapy. However, the lack of knowledge and availability of health professionals, the overloading of health services, which translates into difficulties in access to consultations and the short duration of these, the lack of capacity of the system to promote psychoeducational programs, and the inexistence of follow-up mechanisms are some of the causes responsible for non-adherence [23]. Perhaps, there is a need to adapt the arrangements of the healthcare services to the needs of the growing number of old and very old persons.

The duration of, and the complexity of drug regimens may have consequences for adherence to therapy, since the longer and more difficult the treatment is, the greater the likelihood of discontinuation. Thus, it is necessary to develop simpler schemes, which require small changes in living habits, facilitating adherence. However, these are not the only characteristics on medication that lead to non-adherence. Side effects of some medications, including nausea, vomiting, fatigue and other metabolic changes as well as drug-drug interactions or adverse reactions to medications may also lead to treatment withdrawal [15, 23].

The cognitive and intellectual characteristics of the patients, as well as their personality and behaviour, and their knowledge of the disease and treatment and their motivation are the determinants related to the patient, which lead to non-adherence. To adhere, the patient must understand what is transmitted to him/her and understand the reason for the prescription.

Thus, it is important to focus on health literacy, understood as the ability of individuals to make healthy decisions based on the information provided. Since, adherence is a decision made by the individual based on their beliefs about the consequences of adherence to therapy, when the patients recognize that they have a responsibility to their health and that their behaviour may bring benefits, which improves adherence [15].

To improve the adherence, we must first understand the causes, predictors and determinants responsible for non-adherence. Many of them have been described so far [24]. According to WHO, there are five large sets of factors by which people are non-adherent (**Figure 3**) [25]:

The socioeconomic status is correlated with adherence to therapy. Of these factors, the professional situation, social support, housing conditions, distance to treatment, transportation and medication prices as well as social inequalities are the utmost importance. The existence of support provided either by the family or by friends has a very positive influence on adherence. The lack of involvement of family and friends leads to a state of social isolation, which is one of the determinants of non-adherence [26]. The professional situation is also important, since people with economic difficulties must set priorities in budget management, with food

The relationship between health professionals and patients is extremely important in adherence, since they play a critical role of technical and psychosocial support, giving the individual the basic skills to adhere to medication, developing beliefs about his/her ability to deliver on medications and on the benefits of therapy. However, the lack of knowledge and availability of health professionals, the overloading of health services, which translates into difficulties in access to consultations and the short duration of these, the lack of capacity of the system to promote psychoeducational programs, and the inexistence of follow-up mechanisms are some of the causes responsible for non-adherence [23]. Perhaps, there is a need to adapt the arrangements of the healthcare services to the needs of the growing number of old

The duration of, and the complexity of drug regimens may have consequences for adherence to therapy, since the longer and more difficult the treatment is, the greater the likelihood of discontinuation. Thus, it is necessary to develop simpler schemes, which require small changes in living habits, facilitating adherence. However, these are not the only characteristics on medication that lead to non-adherence. Side effects of some medications, including nausea, vomiting, fatigue and other metabolic changes as well as drug-drug interactions or adverse

The cognitive and intellectual characteristics of the patients, as well as their personality and behaviour, and their knowledge of the disease and treatment and their motivation are the determinants related to the patient, which lead to non-adherence. To adhere, the patient must understand what is transmitted to him/her and understand the reason for the prescription.

Thus, it is important to focus on health literacy, understood as the ability of individuals to make healthy decisions based on the information provided. Since, adherence is a decision made by

reactions to medications may also lead to treatment withdrawal [15, 23].

and housing being the first, often leaving the medication to second option [22].

• socioeconomic factors; • health system related;

• therapy related;

30 Gerontology

• patient related; and • condition related.

and very old persons.

**Figure 3.** Predictors of non-adherence to medication, modified from WHO [25].

The characteristics of the disease such as severity and the symptomatic/asymptomatic nature are factors related to the condition that affects adherence. It is considered that the severity of the disease and the disability that symptoms cause at physical, psychological and social levels are most frequently associated with non-adherence. Individuals with chronic asymptomatic diseases do not adhere to treatment frequently, since the absence of symptoms lower their motivation to take their drugs continuously. In addition, the existence of other concomitant diseases that are treated with various medications (i.e., polypharmacy) is also one of the major factors that contribute to non-adherence [17, 25, 27].

compared to US\$ 19,402 for adherent patients), mainly explained by the increase in hospital admissions (42% of the total value), in terms of higher frequency/duration compared to adherent

Adherence to Medication in Older Adults as a Way to Improve Health Outcomes and Reduce…

http://dx.doi.org/10.5772/intechopen.72070

Simoni-Watilla et al., in 2012, demonstrated that adherent patients with chronic obstructive pulmonary disease had higher costs related to prescription medications than non-adherent patients. However, these were cost-effective since the adherent patients have much lower costs than the non-adherent patients, in terms of hospitalizations and outpatient [33]. Halpern et al., in 2011, drew the same conclusions. Although pharmacy costs were higher in adherent

Ho et al., in 2006, evaluated the impact of non-adherence in Type 2 Diabetes. Higher HbA<sup>1</sup>

blood pressure and LDL cholesterol levels were recorded in non-adherent patients, leading to the increased risk of mortality and morbidity. The economic impact of non-adherence is continually increasing, resulting in long-term complications [35]. Dall et al., in 2010, estimated that \$ 218 billion per year (indirect costs spent for treating diabetes) spent in the USA. Although the cost of treating diabetes is high, representing approximately 7% of health spending, the return on this investment is enormous. Per year, non-insulin and non-antihyperglycemic drugs, insulin and oral hyperglycemic agents cost \$ 776, while avoidable hospitalizations cost \$ 886 per patient [36]. Tang et al., in 2008, found that arthritis adherent patients have higher costs in the pharmacy than non-adherent patients. However, costs related to outpatient, inpatient and laboratory services, related to non-adherence, exceed the amount spent in the pharmacy [37]. Pasma et al., in 2017, demonstrated that decreased adherence leads to an increase in healthcare costs (in anti-

In osteoporosis, poor adherence reduces the potential effectiveness of the drug, resulting in decreased health outcomes and incurring heavy costs. Hiligsmann et al., in 2009 evaluated the economic outcome of non-adherence in osteoporosis patients. Non-adherent patients suffer from more fractures than adherent patients, leading to higher healthcare spending, in com-

In general, all adherent patients have higher drug costs for obvious reasons. However, in the long run, they incur lower expenses than the non-adherent patients, since visits to the emergency rooms, inpatient and outpatient are decreased [40]. One of the reasons that lead the elderly to non-adherence is the high price of medicines. For pensioners with poor retirement, they must manage the budget to pay for basic needs, being in the medicines no longer a priority [41]. One of the ways to overcome this problem is to increase support for the elderly in the purchase of medicines or to reduce their taxes. Although this will mean higher expenses initially,

To improve adherence to therapy in the elderly, there are many questions that need to be addressed and deserve all the attention, once they are the basis for deciding what course to

c,

33

patients, non-adherent patients incurred higher total expenditures [34].

TNF therapies, synthetic DMARDs and rheumatology outpatients) [38].

parison to the costs associated with medication adherence [39].

it will pay off in the long-term [42].

take (**Figure 4**) [43].

**5. Interventions to promote adherence**

patients [32].
