The extent to which a person’s behavior – taking medication, following a diet, and/or executing lifestyle changes, corresponds with agreed recommendations from a health care provider.“Adherence” evokes more the idea of cooperation between the prescriber and his patient and less the connotation of the patient’s passive obedience to the physician’s instructions.
The length of time between initiation and the last dose which immediately precedes discontinuation.
Adherence related sciences represent a complex and rich field because of the fact that it operates across the boundaries between many disciplines: medicine, pharmacy, nursing, behavioral science, sociology, health economics, IT&C, service design, communication, etc1. We will focus on adherence to treatment regimens.
Adherence is a process composed of initiation, implementation and discontinuation. Initiation occurs when the patient takes the first dose of a prescribed medication. Implementation is the extent to which a patient’s actual dosing corresponds to the prescribed dosing regimen, from initiation until the last dose. Finally, discontinuation occurs when the patient stops taking the prescribed medication, for whatever reason(s). As a consequence, non adherence happens in the following situations or combinations thereof: late or non-initiation of the prescribed treatment, sub-optimal implementation of the dosing regimen or early discontinuation of the treatment, known as non-persistence1.
Adherence is an issue for virtually all treatment regimens and all disease conditions. It affects all social classes and cultures. Non-adherence to medication is reported in all geographies, no matter the level of economic development.
Average rates to different treatment regimens2
to medical appointment
Average adherence rates of 10 selected disease conditions2
Sleep disorders 65%
Pulmonary disease 69%
End-stage renal disease 70%
Skin disorders 77%
Seizures/brain disorders 78%
Average adherence rates to hypertensive medication in 5 European regions/countries3
Improving adherence will likely help create a win-win scenario among patients, professionals, payers and pharmaceutical companies.
Poor adherence to medication accounts for substantial worsening of disease, death and increased health care costs4.
It has serious negative consequences for patients, providers, sick funds, employers, pharma industry and society5.
Many studies demonstrated that poor adherence with a therapeutic regimen have a major impact on clinical outcomes and, as a consequence, on patients’ quality of life.
Non adherent patients to digoxin: 2 times more likely to die vs. adherent ones6
20% less hospitalization rates for adherent patients to inhaled corticosteroids7
Risk for diabetes related hospitalizations: 13% adherent vs. 22% non adherent8
Disease flare risk: 13% for adherent patients, 48% for non adherent ones9
The impact of non adherence on costs
The impact of non adherence to medication on health-care resource utilization (HCRU) and therefore costs are likely to work in two ways:
– The immediate and direct impact of poor compliance on medication acquisition costs. Adherence will increase these costs.
– The less immediate and indirect impact of poor adherence on subsequent overall HCRU associated with the condition being treated, as a result of affecting clinical effectiveness, and thus health outcomes.
Non-adherence is likely to reduce medicine acquisition costs but increase subsequent overall HCRU. For people who continue to obtain prescriptions but stockpiling their medicines, the impact is keeping the same level of acquisition and increasing the indirect costs10.
Improved adherence to medication produces substantial medical savings11
Roebuck et al. studied the relationship between medication adherence and the use and cost of health services in patients who had one or more of the following four chronic vascular conditions: congestive heart failure, hypertension, diabetes, and dyslipidemia.
This study shows that adherent patients spent significantly less than nonadherent patients, after combining the increase due to Rx pharmacy refills (in green on the graph) with the medical costs due to hospitalizations or emergency department visits (in purple on the graph).
Impact Of Medication Adherence In Chronic Vascular Disease On US Health Services Spending
(costs adherent vs. non adherent patients)
Annual per person savings due to adherence (in orange on the graph) amounted to $7,823 for congestive heart failure, $3,908 for hypertension, $3,757 for diabetes, and $1,259 for dyslipidemia.
Ascertaining barriers for compliance: policies for safe, effecctive, and cost effective use of medicines in Europe, Final report, june 2012
DiMatteo, Variations in Patients’ Adherence to Medical Recommendations, Med Care 2004;42: 200–209
Morrison et al., Predictors of Self-Reported Adherence to Antihypertensive Medicines: A Multinational, Cross-Sectional Survey, Value in Health. 18(2), 206-216
Osterberg, Adherence to medication, N Engl J Med 2005;353:487-97
Walid et al., A Review of Barriers to Medication Adherence: A Framework for Driving Policy Options, RAND Health report, 2009
Miura et al., Effect of digoxin noncompliance on hospitalization and mortality in patients with heart failure in long-term therapy: a prospective cohort study. Eur J Clin Pharmacol. 2001;57:77-83
Balkrishnan R, Christensen DB. Inhaled corticosteroid nonadherence and immediate avoidable medical events in older adults with chronic pulmonary ailments. J Asthma. 2000;37:511-517.
Sokol et al., Impact of medication adherence on hospitalization risk and healthcare cost, Med Care 2005;43:521-30.
Contreras-Yáñez et al., Inadequate therapy behavior is associated to disease flares in patients with rheumatoid arthritis who have achieved remission with disease-modifying antirheumatic drugs, Am J Med Sci. 2010 Oct;340(4):282-90
Hughes et al., Methods for Integrating Medication Compliance and Persistence in Pharmacoeconomic Evaluations., Value Health 2007;10:498-509
Roebuck et al., Medication Adherence Leads To Lower Health Care Use And Costs Despite Increased Drug Spending, HEALTH AFFAIRS 30, NO. 1 (2011): 91–99