Association between Big Five personality factors and medication adherence in the elderly

Abstract Introduction Adherence to medications can be associated with circumstances related to the patient, with the pathology, with cultural health beliefs, with habits, and with quality of life. Behavioral patterns can also directly influence a patient’s pharmacological adherence, since they are related to their perception and understanding of their own health status and of their drug and non-drug treatments. Objective To investigate the association between adherence to pharmacological treatment and personality factors, sociodemographic variables, and economic data in the elderly. Methods Cross-sectional descriptive study. The population studied were elderly people registered with the Family Health Strategy of Porto Alegre and enrolled on the Brain Aging Program (PENCE), from March 2013 to November 2015. Sociodemographic data, pharmacological adherence, and personality traits were evaluated. Exclusion criteria were incomplete data in the personality and pharmacological adherence assessments; cognitive impairment, evaluated using the instrument Mini-Mental State Examination (MMSE), or not having carried out this assessment. Results A total of 123 individuals were included with a mean age of 71.35±7.33 years, 58.6% of whom reported some level of non-adherence to their medication regime (low and moderate adherence). Elderly people with low adherence had significantly higher mean scores in the Neuroticism factor, while those with high adherence had significantly higher mean scores in the Agreeableness and Conscientiousness factors. Conclusion The study suggests that pharmacological adherence among the elderly is negatively associated with the Neuroticism personality trait, while the Agreeableness and Conscientiousness traits are positively associated.


Introduction
In Brazil, 85% of the elderly population have at least one chronic disease, and approximately 15% have multiple comorbidities, such as hypertension, diabetes, and cardiovascular problems. 1 This scenario results in the elderly using greater numbers of different medications, making the practice of polypharmacy common. 2 Use of various medications combined with therapeutic complexity can make adherence to treatment more difficult. High rates of non-adherence, which can exceed 80%, have been observed in the elderly when compared to the general population. 3 This non-adherence can have a detrimental influence on patient health status and may generate other complications, such as a reduced quality of life, greater risk of hospitalization, and increased health care costs. 1,3 Adherence to medications is associated with several circumstances related to the patient (cognitive function, impaired sight, lack of understanding, inability to administer different medications), with the pathology, with cultural health beliefs, with habits, and with quality of life, as well as with the relationship with the healthcare team. 4 It is important to point out that behavioral patterns can also directly influence patients' pharmacological adherence, as they are related to their perception and understanding of their own health status and drug and non-drug therapies. 3,5 Personality traits are enduring behavioral patterns that tend to be stable throughout life. They set the standards of behavior and interpersonal relationships. 6 9 The Neuroticism factor was also associated with poorer adherence to the medication program in elderly patients undergoing preventive treatment for dementia. 10 In order to improve therapeutic adherence, interventions could take personality traits and the reasons for adherence being less than ideal into consideration. 7 Therefore, the present study aimed to investigate associations between adherence to pharmacological treatment and five-factor model personality traits, sociodemographic variables, and economic data in the elderly.

Study design
The study design is cross-sectional and descriptive and this study is part of the umbrella project entitled the The NEO-FFI instrument was used to assess personality traits. 13 This instrument is a short version of the Revised NEO Personality Inventory, which has been translated into and validated for Portuguese. 14  The results for pharmacological adherence and personality traits were also analyzed, demonstrating that elderly people with low adherence had significantly higher mean scores for the Neuroticism factor, mainly when compared with the moderate subset (p = 0.015).
While those with high adherence had significantly higher mean scores for Agreeableness, especially when compared to the low subset (p = 0.024), and for Conscientiousness, in the comparisons high versus low adherence subsets (p = 0.016) and also moderate versus low subsets (p = 0.044) ( Table 2).

Discussion
The present study showed that most of the elderly participants were non-adherent to their drug treatments.
The literature similarly demonstrates that the elderly population has high rates of non-adherence. A study in Salto Grande (São Paulo, Brazil) revealed that 85.3% of elderly people did not adequately adhere to their prescribed drug treatments. 17 A study in Cuiabá (Mato Grosso, Brazil) found 80% of low adherence among the elderly. 5 Low adherence among geriatric patients is due to emergence of multiple chronic diseases developed over the course of the aging process, which make polypharmacy and self-medication practices more likely. These are associated with adverse reactions and pharmacological interactions. 1,18 Other factors are also related to low adherence to medications in the elderly, such as the complexity of administering dosing schedules, difficulty in swallowing, denial or fear of illnesses, forgetfulness problems, low self-esteem, interruption of treatment for alcohol consumption, low economic income, and educational level. 1,4,18 The literature shows that individuals with worse socioeconomic levels, represented by low income and low educational levels, have lower adherence to pharmacotherapy. 19 This is due to possible difficulties in understanding the treatment protocols and health guidelines, in addition to financial problems, which may interfere with access to medicines. 19 In the present study, this association was not evidenced due to the homogeneous profile of the population, which was

Conclusion
The present study suggests that adherence to pharmacological treatment in the elderly is negatively