A Systematic Review of Barriers to Medication Adherence in the Elderly: Looking Beyond Cost and Regimen Complexity

doi:10.1016/j.amjopharm.2011.02.004

The American Journal of Geriatric Pharmacotherapy

Volume 9, Issue 1, February 2011, Pages 11-23

https://doi.org/10.1016/j.amjopharm.2011.02.004 Get rights and content

Abstract

Background

Medication nonadherence is a common problem among the elderly.

Objective

To conduct a systematic review of the published literature describing potential nonfinancial barriers to medication adherence among the elderly.

Methods

The PubMed and PsychINFO databases were searched for articles published in English between January 1998 and January 2010 that (1) described “predictors,” “facilitators,” or “determinants” of medication adherence or that (2) examined the “relationship” between a specific barrier and adherence for elderly patients (ie, ≥65 years of age) in the United States. A manual search of the reference lists of identified articles and the authors' files and recent review articles was conducted. The search included articles that (1) reviewed specific barriers to medication adherence and did not solely describe nonmodifiable predictors of adherence (eg, demographics, marital status), (2) were not interventions designed to address adherence, (3) defined adherence or compliance and specified its method of measurement, and (4) involved US participants only. Nonsystematic reviews were excluded, as were studies that focused specifically on people who were homeless or substance abusers, or patients with psychotic disorders, tuberculosis, or HIV infection, because of the unique circumstances that surround medication adherence for each of these populations.

Results

Nine studies met inclusion criteria for this review. Four studies used pharmacy records or claims data to assess adherence, 2 studies used pill count or electronic monitoring, and 3 studies used other methods to assess adherence. Substantial heterogeneity existed among the populations studied as well as among the measures of adherence, barriers addressed, and significant findings. Some potential barriers (ie, factors associated with nonadherence) were identified from the studies, including patient-related factors such as disease-related knowledge, health literacy, and cognitive function; drug-related factors such as adverse effects and polypharmacy; and other factors including the patient-provider relationship and various logistical barriers to obtaining medications. None of the reviewed studies examined primary nonadherence or nonpersistence.

Conclusion

Medication nonadherence in the elderly is not well described in the literature, despite being a major cause of morbidity, and thus it is difficult to draw a systematic conclusion on potential barriers based on the current literature. Future research should focus on standardizing medication adherence measurements among the elderly to gain a better understanding of this important issue.

Introduction

Medications are frequently used in the elderly to improve quality of life, extend life-expectancy, and cure or mitigate disease. It is clear, however, that the elderly often fail to adhere to prescribed medications, which can lead to unwelcome clinical and economic consequences.1, 2, 3

For a variety of reasons, patients do not adhere to their prescribed medication regimens. One conceptual model of barriers to adherence describes patient, prescriber, and health care system factors.⁴ Others have developed more detailed conceptual models specific to the elderly.2, 3, 5 Each model highlights the fact that the medication use process is affected by many factors in older adults, including drug- and patient-related issues, such as patient representations of their illness, cognitive function, medication side effects, and patient-prescriber relationships. Furthermore, because older adults often suffer from multiple comorbid conditions and thus use more medications than their younger counterparts, medication nonadherence can have drastic deleterious health effects on the elderly.² Therefore, finding potential areas for interventions to help improve this process should be a top priority of health care providers.

Most modifiable barriers that hinder an older adult from adequately adhering to prescribed medications are not clearly described in the literature, with the exception of cost, which is well described.6, 7, 8, 9, 10, 11 Prior reviews of medication adherence in the elderly cite inconsistencies across studies and draw few solid conclusions; in addition, these reviews contain many dated studies, and some include patients <65 years of age.1, 2, 12

Given this background and the objective to identify barriers to adherence specific to patients in the United States, a systematic review of the published literature was conducted that described potential nonfinancial barriers to medication adherence among patients ≥65 years.

Section snippets

Data Sources

The PubMed and PsychINFO databases were searched, covering the period from January 1998 to January 2010, limiting the field to English-language publications, and omitting the publication types of “letters,” “editorials,” and “comments.” The year 1998 was used as the baseline year for the search because a previous review of medication adherence in the elderly was published using the years 1962 to 1997.¹ The search strategy utilized both MeSH and non-MeSH terms, as outlined in Figure 1.

Eligibility Criteria

The search

Results

Nine articles that met inclusion criteria in this systematic review were included. Details from the studies in this review, including study sample, disease studied, method of assessing adherence, barriers discussed, and findings, are summarized in Table I. Four studies used pharmacy records or claims data to assess adherence, 2 studies used pill count or electronic monitoring, and 3 studies used other methods to assess adherence. The 9 articles included in this review varied in their methods of

Discussion

There are no known prior systematic reviews of the nonfinancial barriers to medication adherence among the US elderly (ie, aged ≥65 years). This search found only 9 studies that met the inclusion criteria, and each one studied a different population or disease or used a different assessment of medication adherence, making a clear synthesis of the literature extremely difficult. Studies of adherence have been burdened by heterogeneity for decades,26, 27, 28 and recent literature seems to be no

Conclusions

This systematic review found a large amount of heterogeneity in the methods used to define, assess, and measure medication adherence in the elderly; thus, it is not possible to make systematic conclusions. However, several potentially modifiable barriers to medication adherence were identified. The current state of the literature regarding modifiable barriers to medication adherence among older adults is limited and suggests a great need for well-designed studies and a consistently measured

Acknowledgments

This study was supported by an Agency for Healthcare Research and Quality grant (T32 HS00046-14), a National Institute of Aging Grant (T32 AG021885), and Mehlman Vogel Castagnetti. Dr. Gellad is additionally supported by a VA HSR&D Career Development Award. The authors would like to thank Joseph T. Hanlon, PharmD, MS, for his assistance with earlier drafts of this manuscript.

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Review articleA Systematic Review of Barriers to Medication Adherence in the Elderly: Looking Beyond Cost and Regimen Complexity

Abstract

Background

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Data Sources

Eligibility Criteria

Results

Discussion

Conclusions

Acknowledgments

Clin Ther

Am J Geriatr Pharmacother

Clin Ther

Clin Ther

Clin Ther

Am J Geriatr Pharmacother

Value Health

Medication non-adherence in the elderly: How big is the problem?

Drugs Aging

Adherence to medication

N Engl J Med

Medication adherence and aging

The effects of prescription drug cost sharing: A review of the evidence

Am J Manag Care

Cost-related medication nonadherence among elderly and disabled medicare beneficiaries: A national survey 1 year before the medicare drug benefit

Arch Intern Med

Prescription drug cost sharing: Associations with medication and medical utilization and spending and health

JAMA

Patients at-risk for cost-related medication nonadherence: A review of the literature

J Gen Intern Med

Race/ethnicity and nonadherence to prescription medications among seniors: Results of a national study

J Gen Intern Med

Medicare prescription drug benefit progress report: Findings from a 2006 national survey of seniors

Health Aff (Millwood)

Review article
A Systematic Review of Barriers to Medication Adherence in the Elderly: Looking Beyond Cost and Regimen Complexity