Adherence: A Concept Analysis
Tiffany Bruno

Adherence: A Concept Analysis The concept of adherence to medication regimens has been an ongoing area of study across medicine, psychology, nursing and pharmacology. First, I think it is important to clarify the difference between compliance and adherence. The term “adherence” implies a more collaborative active role between the patients and their providers whereas compliance implies a passive role to health-care on the part of the patient (Carpenter 2005). The word adhere originated in the 15th century from the Latin “’ad-“ (to) + “haerere” (to stick)” (The American Heritage College Dictionary, 1993, p. 16). Adhere is defined as “to stick fast; remain attached” and/or “to be a devoted follower or supporter” (The American Heritage College Dictionary, 1993, p. 16). Adherence, then, is the “process or condition of adhering” or the “faithful attachment; devotion” (The American Heritage College Dictionary, 1993, p. 16). As a nurse practitioner, it is vitally important that we equip our patients with the proper information and instructions regarding treatment regimens to increase adherence and improve patient outcomes. As a nurse practitioner in the area of oncology, medication adherence to chemotherapy and targeted therapy agents, the need for a thorough understanding of adherence, is heightened due to the complexity surrounding the physiological implications of cancer and the pharmacokinetics of the treatment. Not only do the oral chemotherapy/targeted therapy medications have increased number and severity of side effects, they are likely to have more drug interactions and rigid, precise instructions. Most people understand the importance of taking chemotherapy/targeted therapy drugs as prescribed because of the fear that the word ‘cancer’ evokes. To better understand how to increase medication adherence, an unambiguous definition of adherence, as well as antecedents, criteria, and consequences need to be identified.
Review of Literature
Nursing
Schaffer & Yoon (2001) describe medication adherence as a collaborative, interactive patient-provider relationship. Medication adherence is the degree of consistency between the prescribed regimen and the patient's actual dosing history (Schaffer & Yoon, 2001). Medication adherence is important as it provides not only a better clinical outcome for the patient, but has been shown to reduce healthcare costs associated with unnecessary hospitalization and emergency room visits (Schaffer & Yoon, 2001). Several characteristics of medication adherence were identified in the article (Schaffer & Yoon, 2001). First, patients with a clear understanding of the purpose of the drug and how to properly take the drug were more likely to adhere (Schaffer & Yoon, 2001). Second, medication adherence increased when the patients believed in the medication’s efficacy and had confidence in his/her ability to adhere to the regimen as prescribed (Schaffer & Yoon, 2001). Financial constraints, such as lack of insurance or low income, also negatively affect adherence (Schaffer & Yoon, 2001). Patients that experience adverse effects; are in the early stage of treatment; and busy, middle-aged adults are less likely to adhere to a treatment regimen (Schaffer & Yoon, 2001). It is necessary that the clinician allows the patient to openly discuss concerns or raise questions regarding the medication or condition, share treatment goals and anticipate barriers to adherence while equipping the patient with tools to overcome the obstacles related to adherence (Schaffer & Yoon, 2001). Schaffer and Yoon (2001) also point out that regimens with two or more doses per day have lower rates of adherence. Strategies such as establishing a good provider-patient relationship to increase emotional rapport, positive conversation and clearly informing the patient of the medication and condition will increase adherence (Schaffer & Yoon, 2001). A study done by Van Camp, Huybrechts, Van Rompaey and Elseviers (2011) evaluated the relationship of adherence to phosphate binders for chronic dialysis patients. Psychological factors such as anxiety about potential side effects or adverse events, perceived benefits of taking the medication and confidence in taking the medication were the main barriers of adhering to the regimen (Van Camp, et al., 2011). The Medication Event Monitoring System (MEMS) was used to measure patient adherence to phosphate binders over the 17 weeks (Van Camp, et al., 2011). The MEMS devise is able to capture the date and time the medication pill box was opened and presumed that the phosphate binder was taken (Van Camp, et. al., 2011). Electronically monitoring medication adherence has shown to be effective as the patient is aware of the intervention, hence more likely to adhere because of the monitoring (Van Camp et al., 2011). The increased adherence based on the MEMS microchip was confirmed by the decrease in the patient’s calcium and phosphate levels (Van Camp, et al., 2011). Nurse-led education and counseling was shown to increase adherence to phosphate binders, but larger sample size and longevity studies are needed to substantiate the correlation (Van Camp, et al., 2011). Buchmann (1997) studied how the relationship between self-efficacy and social power affects adherence. The author used the terms adherence and compliance interchangeably, yet provided a definition that distinguished the two concepts (Buchmann, 1997). “Compliance is a willingness to follow or consent to the wishes of another person, whereas adherence is the action of sticking to, supporting or following a person or an idea” (Buchmann, 1997, p. 132). It was assumed that the thought or cognition (compliance) leads to the action (adherence) (Buchman, 1997). The stronger the patient perceives his/her ability to accomplish a task, such as following a medication regimen, the more likely the patient will successfully adhere to a medication regimen (Buchmann, 1997). Carpenter (2005) researched the correlation of perceived threat in adherence. Adherence is differentiated from compliance in that with adherence, the patient is actively involved in the treatment regimen; whereas, with compliance, the patient plays a more passive role regarding healthcare decisions (Carpenter, 2005). The author explains that perceived threat (the patient’s anticipation of harm, loss of control or interference with basic needs) will negatively affect adherence to a treatment regimen. To increase adherence by decreasing the patient’s perceived threat, the nurse can provide education on the disease and treatment. This will enable the patient to be more rational and better able to understand the need for the treatment and that the benefits outweigh the risks (Carpenter, 2005). Chummun and Bolan (2013) conducted a literature review regarding how patient beliefs affect adherence to medication regimens. Adherence was identified “as the extent to which a person’s medication-taking behavior corresponds with the agreed recommendations of a healthcare provider” (Chummun & Bolan, 2013, p. 270). Of the six studies reviewed, the main beliefs identified as barriers to medication adherence are “necessity of the medication, misconceptions about the medication [and the] benefits and side effects of the medication” (Chummun & Bolan, 2013, p. 274). The analysis also articulates the importance of identifying the nonadherence as either intentional or unintentional so that the appropriate actions can be taken to improve adherence (Chummun & Bolan, 2013). Intentional nonadherence occurs when the patient makes an active decision to not take a medication whereas unintentional nonadherence occurs when the patient forgets to take a medication, doesn’t understand medication instructions, or cannot afford to pay for the medication (Chummun & Bolan, 2013). The literature review of adherence in the discipline of nursing identified the following antecedents: self-efficacy, financial situation, provider influence, perception of adverse effects, knowledge, insurance, simple and clear regimen instructions, perceived value and outcome expectation of treatment adherence. Criteria for adherence include agreement, therapeutic alliance, and acceptance. Consequences to adherence are decreased healthcare costs, reduced mortality and improved quality of life.
Pharmacology
Of the numerous methods to measure medication adherence, researchers have failed to develop a gold standard (Vermeire, Hearnshaw, Van Royen & Denekens, 2001). This also leads to the inability to accurately measure adherence (Vermeire et al., 2001). The method of direct measurement in detection of chemical metabolite in urine or blood is expensive, unfeasible and cannot be used for all medications (Vermeire et al., 2001). Indirect measurements such as interviews, prescription filling dates, pill counts are used more frequently to asses adherence (Vermeire et al., 2001). The most precise method of measurement is that of the MEMS which uses microprocessor technology to monitor the frequency, date and time of when the medication box was opened (Vermeire et al., 2001). Vermeire et al., (2001) identifies poor communication, unresolved patient concerns, fear of side effects, patient beliefs regarding health and illness, patient “ignorance about important issues, such as the nature of the disease and the nature of the treatments and” effectiveness are barriers to adherence (p. 336). Adherence research should be focused on the patient’s beliefs regarding medication-taking behavior (Vermeire et al., 2001). Hughes (2004) explored adherence in the elderly population. Adherence is the patient’s willingness to agree with the prescriber’s recommendation. The author points out that the majority of research done has had vague definitions of adherence (Hughes, 2004). Some barriers to adherence were identified as poor cognitive ability, complex administration regimens, difficult medication packaging, multiple morbities, polypharmacy and lack of social support (Hughes, 2004). Pharmacists can play an active role in increasing adherence by collaboratively working with physicians and nurses in educating the patient about the medication (Hughes, 2004). Akerblad, Bengtsson, Ekselius and von Knorring (2003) identified adherence as the active participation of the patient and the clinician in forming a therapeutic alliance. Akerblad et al., (2003) conducted a study in which 1000 patient’s diagnosed with depression and started on selective serotonin reuptake inhibitor were monitored by questioning, detecting serum levels of sertraline and desmethylsertraline, and a composite index. The patient’s also received extensive educational counseling and materials when started on the medication (Akerblad et al., 2003). Those patient’s that did not complete the questioning, did not keep appointments and/or the patient’s serum drug levels were low were labeled as nonadherent (Akerblad et al., 2003). The findings confirmed that patient education is crucial in increasing medication adherence (Akerblad et al., 2003). The antecedents related to adherence in the pharmacology discipline are education, cognitive ability and social support. Criteria found were agreement and devotion. Consequences identified in the literature include empowerment, patient satisfaction and improved patient outcomes.
Psychology
The issue of adherence in psychology is of particular importance as the pathology of psychological disorders interferes with rational routine tasks. Leclerc, Mansur and Brietzke (2013) analyzed the literature to identify the determinants of treatment adherence in bipolar disorder. Leclerc et al., 2013 defines treatment adherence as “the extent to which a patient follows the medical instructions of their health-care provider, and plays a key role in coming to an agreement about its own treatment” (p. 248). The functional status of a person with bipolar disorder is altered in the self-care, social, occupational and educational realms which interfere with treatment adherence (Leclerc et al., 2013). Patient-related factors associated with adherence include gender (women are more likely to adhere to treatment), marital status (single patients have lower adherence) and the absence of alcohol and/or drug use (Leclerc et al., 2013). Psychoeducation continues to be the most effective intervention to increase treatment adherence (Leclerc et al., 2013). Evers, Klusmann, Schwarzer and Heuser (2012) conducted a trial to study the relationship of intention and self-efficacy to adherence. The participants were randomly selected to be either a computer class or a physical activity class (Evers, Klusmann, Schwarzer and Heuser, 2012). The study found that women who developed coping plans (interventions to overcome certain obstacles in preventing their attendance to the class) had higher rates of adherence than those who did not develop a plan (Evers, Klusmann, Schwarzer and Heuser, 2012). Identifying possible barriers to adherence and developing a plan as to how to resolve the issue was shown to increase adherence (Evers, Klusmann, Schwarzer and Heuser, 2012). Self-efficacy was also shown to increase adherence (Evers, Klusmann, Schwarzer and Heuser, 2012). DiMatteo (2004) performed a meta-analysis regarding the relationship of social support and treatment adherence. The author defined adherence as the patient’s acceptance and ability to carry on with treatment recommendations (DiMatteo, 2004). Patient’s that are married, have close and healthy family relationships, and are living with someone, were shown to increase adherence (DiMatteo, 2004).
The discipline of psychology yielded the antecedents of adherence as social support, acceptance of disease, understanding the need for treatment and a plan to overcome potential obstacles. Criteria include cooperation and agreement. Consequences of adherence in psychology literature show a decrease in suicide rates, increased quality of life and improved morbidity.
Medicine
Thivat et al., (2013) recently conducted a study analyzing oral anticancer agent adherence in cancer patients. Patient’s adherence to either capecitabine or an aromatase inhibitor (anastrozole or letrozole) was monitored using the MEMS system which measures the date, time, frequency of when the pill bottle was accessed (Thivat et al., 2013). The MEMS microchip was analyzed when the patient came to the clinic for regular follow up visits (Thivat et al., 2013). Medication cost, regimen complexity and patient beliefs were identified as factors affecting adherence (Thivat et al., 2013). The authors also point out that food intake largely influences the absorption of capecitabine and lapatinib which present another aspect of adherence that is difficult to measure (Thivat et al., 2013). The study showed that further research is needed, patient education is a vital aspect of adherence and the MEMS system is a valid measurement method (Thivat et al., 2013). Ruddy et al. (2012) states “optimal adherence occurs when no doses are skipped, doubled, or taken at the wrong time or dosage” (p. 3075). The study evaluated adherence to oral chemotherapy regimen for older women with breast cancer (Ruddy et al., 2012). Medication calendars were used because MEMS caps were not available to measure adherence (Ruddy et al., 2012). Women with later stage disease had higher rates of adherence than those women who had early stage breast cancer (Ruddy et al., 2012). The study found that lower adherence was related to increased risk of cancer recurrence (Ruddy et al., 2012). Polypharmacy is also correlated to lower treatment adherence (Ruddy et al., 2012). Bottonari et al., (2012) examined adherence in patients with depression and HIV. Memory lapse, substance abusse, social support and coping style were associated with treatment adherence for patients with HIV (Bottonari et al., 2012). The following characteristics may be associated with depressed patients and low treatment adherence: forgetfulness, female, younger age, initial episode versus recurrent depression, low self-esteem and less educated patients (Bottonari et al., 2012). Interestingly, research has shown that the use of anitdepressants in HIV-infected patients has increased treatment adherence to antiretroviral medications (Bottonari et al., 2012). The study used self-report and chart reviews methods to evaluate medication adherence (Bottonari et al., 2012).
Denois, Poirson, Nourissat, Jacquinn, Guastalla, and Chauvin (2011) conducted a qualitative study to evaluate factors associated with poor adherence to oral chemotherapy medications. The patient’s perception and description of the oral chemotherapy treatment was the focus of the study (Denois et al., 2011). Non-adherence was due to misunderstanding the instructions whereas adherence was associated with social support from family and friends, as well as, using a calendar to track the medication cycles (Denois et al., 2011). Antecedents related to adherence include the patient’s perception of the illness and treatment; and active participation in the decision making process. Memory problems, substance abuse and lack of social support were strong antecedents of nonadherence. Criteria include commitment and cooperation. Consequences of adherence are decreased side effects and improved health outcomes.
Summary of Literature Review Adherence as reviewed across the disciplines of nursing, pharmacology, psychology and medicine provides consistent antecedents, criteria and consequences. More research needs to be done to identify interventions that will improve adherence. The concept of adherence is in great need of reliable and valid methods of measurement.
Selected Antecedents, Criteria and Consequences
Table 1
-------------------------------------------------
Antecedents, Criteria and Consequences to Bonding
-------------------------------------------------
________________________________________________________________________
-------------------------------------------------
Antecedents Criteria Consequences
Knowledge Agreement Improved health outcomes
Social Support Cooperation Empowerment
Perception of harm/adverse events Commitment Improved quality of life
Active participation therapeutic alliance Reduced mortality
Relationship with clinician Decreased healthcare costs
Socioeconomic Status
Rationale for Selection
Antecedents
Knowledge as an antecedent of adherence encompasses the importance that the patient has a clear understanding of the medical condition and the reason the medication is prescribed. Social supports includes marital status, support groups, close circle of friends and family. The antecedent of perception of harm/adverse events encompasses the extent to which the patient’s fear of disease, treatment or side effects influences adherence. Active participation of the patient in his/her healthcare regimen improves treatment adherence. A therapeutic relationship between the patient and provider fosters an environment in which the patient is able to comfortably express any concerns regarding treatment or side effects. If the patient articulates his/her concerns, the provider can assist in equipping the patient with the knowledge or tools to improve adherence. Socioeconomic status can influence the ability of the patient to get transportation to appointments or the pharmacy; lack of insurance and low income are likely to hinder treatment adherence.
Criteria
The criteria of adherence include agreement, cooperation, therapeutic alliance and commitment. The patient needs to agree to the recommendations for treatment provided by the clinician. Cooperation between the patient and healthcare provider is vital in developing a treatment plan. The presence of a therapeutic alliance between the patient and clinician will foster an open relationship to encourage communication and mutual understanding.
Consequences
The main consequences repeatedly identified in the literature include improved health outcomes, reduced mortality, improved quality of life, patient empowerment and decreased healthcare costs.
Personal Definitions of Adherence
Theoretical Definition
Adherence is a commitment and agreement between the patient and healthcare provider to build a therapeutic alliance regarding treatment goals.
Operational Definition Adherence is most accurately measured using the MEMS (Medication Event Monitoring System) (Vermeire et al., 2001 and Thivat et al., 2013). The MEMS device is able to track the date and time for each medication retrieval event (Thivat et al., 2013). MEMS, in concordance with patient report, a more realistic understanding of medication adherence could be obtained.
Summary
Adherence is an important concept related to the discipline of nursing. The nurse is at the front line of patient care. The knowledge and compassion vital to nursing provides a strong base to develop a therapeutic alliance with patients and deliver comprehensive education to patients to improve medication adherence. Currently, I work in an oncology clinic. The number of oral anticancer drugs is quickly increasing. Patient education is the most important aspect of medication adherence. For a patient to receive a cancer diagnosis and begin an oral anticancer agent in the same day is overwhelming and a bad time to provide education to the patient regarding a new medication. Initial and follow up teaching are very important, but the literature clearly established that an open, therapeutic, patient-provider relationship greatly increases adherence.

References
Akerblad, A., Bengtsson, F., Ekselius, L., & von Knorring, L. (2003). Effects of an educational compliance enhancement programme and therapeutic drug monitoring on treatment adherence in depressed patients managed by general practitioners. International Clinical Psychopharmacology, 18, 347-354.
Blackwell, B. (1979). Treatment adherence: a contemporary overview. Psychosomatics,
20(1), 27-35.
Bottonari, K. A., Tripathi, S. P., Fortney, J. C., Curran, G., Rimland, D., Rodriguez-
Barradas, M., & ... Pyne, J. M. (2012). Correlates of Antiretroviral and
Antidepressant Adherence Among Depressed HIV-Infected Patients. AIDS
Patient Care & Stds, 26, 265-273. doi:10.1089/apc.2011.0218
Buchmann, W. (1997). Adherence: a matter of self-efficacy and power. Journal Of
Advanced Nursing, 26, 132-137. doi:10.1046/j.1365-2648.1997.1997026132.x
Carpenter, R. (2005). Perceived threat in compliance and adherence research. Nursing
Inquiry, 12, 192-199. doi:10.1111/j.1440-1800.2005.00269.x
Chummun, H., & Bolan, D. (2013). How patient beliefs affect adherence to prescribed medication regimens. British Journal Of Nursing, 22, 270-276.
Denois, V., Poirson, J. J., Nourissat, A. A., Jacquinn, J. P., Guastalla, J. P., & Chauvin F.
F. (2011). Adherence with oral chemotherapy: results from a qualitative study of the behaviour and representations of patients and oncologists. European Journal
Of Cancer Care, 20, 520-527. doi:10.1111/j.1365-2354.2010.01212.x
DiMatteo, M. (2004). Social support and patient adherence to medical treatment: a meta- analysis. Health Psychology, 23, 207-218.
Evers, A., Klusmann, V., Schwarzer, R., & Heuser, I. (2012). Adherence to physical and mental activity interventions: Coping plans as a mediator and prior adherence as a moderator. British Journal Of Health Psychology, 17, 477-491. doi:10.1111/j.2044-8287.2011.02049.x Hughes, C. (2004). Medication non-adherence in the elderly: how big is the problem?.
Drugs & Aging, 21, 793-811.
Leclerc, E., Mansur, R. B., & Brietzke, E. (2013). Determinants of adherence to treatment in bipolar disorder: A comprehensive review. Journal Of Affective
Disorders. doi:10.1016/j.jad.2013.01.036
Ruddy, K., Pitcher, B., Archer, L., Cohen, H., Winer, E., Hudis, C., & ... Partridge, A.
(2012). Persistence, adherence, and toxicity with oral CMF in older women with early-stage breast cancer (Adherence Companion Study 60104 for CALGB
49907). Annals Of Oncology: Official Journal Of The European Society For Medical Oncology / ESMO, 23, 3075-3081. doi:10.1093/annonc/mds133
Schaffer, S., & Yoon, S. (2001). Evidence-based methods to enhance medication adherence. Nurse Practitioner, 26, 44-54.
The American Heritage College Dictionary (3rd ed.). (1993). Boston, MA: Houghton
Mifflin.
Thivat, E.E., Van Praagh, I.I., Belliere, A.A., Mouret-Reynier, M.A., Kwiatkowski, F.F.,
Durando, X.X., &...Chevrier, R.R. (2012). Adherence with Oral Oncologic
Treatment in Cancer Patients: Interest of an Adherence Score of All Dosing
Errors. Oncology, 84, 67-74. doi:10.1159/000342087
Van Camp Y.P., Huybrechts, S., Van Rompaey, B., & Elseviers, M. (2012). Nurse-led education and counselling to enhance adherence to phosphate binders. Journal Of
Clinical Nursing, 21, 1304-1313. doi:10.1111/j.1365-2702.2011.03967.x
Vermeire, E., Hearnshaw, H., Van Royen, P., & Denekens, J. (2001). Patient adherence to treatment: three decades of research. A comprehensive review. Journal Of Clinical Pharmacy & Therapeutics, 26, 331-342.