Adherence: The Furnace Filter Analogy
If you ask furnace repairmen todescribe the greatest frustration ofthe trade, you will hear a familiarstory. Even though the repairmenremind people and offer ways for themto remember, most people fail to cleanor replace their furnace filters monthly.If people do remember, they may notdo the job correctly or well. That problemsounds similar to a problem thathealth care providers face every day:medication and treatment adherence.Consider these facts:
More than 29% of adults have hypertension(HTN)1,2 and are at increasedrisk for adverse outcomes. Althougheffective treatment reduces risk,3,4most patients with HTN have poorlycontrolled blood pressure,5,6 and up to70% of patients are nonadherent withprescription medication.1,7-9
Among diabetics treated with sulfonylureas,adherence is estimated tobe as low as 10% to 50%.10
Among HIV-infected people, high-leveladherence (in the range of 90% to95% of doses taken correctly) is necessaryto prevent viral resistance and toimprove immunologic, virologic, andclinical outcomes. Regardless, adherenceoften is reported to be less than70%.11
Most pharmacists know some of thefactors that increase the risk of nonadherence:
- Increasing numbers of drugs anddoses
- Difficult administration routes ortiming
- Silent or symptomless diseases
- Cost of medications
- Intolerable side effects
In the past, health care clinicianshave used patient self-report, clinicianimpression, pill counts, pharmacologictracers, and electronic measurementdevices to assess adherence. Examinationof pharmacy claims data is arecent method that allows access toaggregate data on medication dosingand refill patterns. The new buzzwordis medication possession ratio(MPR),12,13 which now is used frequentlyas an adherence measure.10,12-25 (seesidebar).
Poor medication adherence is differentfrom poor furnace filter maintenancein that furnace repairmen do nothave aggregated statistics about nonadherenceas pharmacists do. Ultimately,statistics do not create changein and of themselves, and direct-careclinicians have to intervene. Medicationadherence and furnace filtermaintenance are similar in that accessand cost can be barriers, and culturalbeliefs or misinformation also may beimportant.
Hypertensive patients, for example,often indicate that they become nonadherentbecause they believe thatthey are cured (46%), or they perceivethat their prescribing clinician directedthem to stop (25%).26 Patients may forgetto take medications, misunderstandwhen or how to take them, takeextra doses to treat stubborn symptoms,or consciously decide to stoptaking medications.27 Clinicians may beignorant of these problems and mayinterpret unidentified nonadherence aspoor drug effectiveness.
Communication technique is key toimproving adherence, especially communicationthat employs a patient-centeredapproach that allows patientsto participate in shared decision making.28-31 Unfortunately, physicians rarelyengage patients in decision making:often they just inform patients of theneed for medication.30 They also areunlikely to question patients aboutmedication-taking behaviors.32
Clinicians cannot expect to changepatient behaviors without first knowingcurrent medication-taking behaviors.Asking questions is the cornerstone ofthe approach, and most communicationexperts recommend using directand information-intensive approachesto assessing adherence.33 Despite decades of education directed at healthcare providers to improve communication,providers frequently use inappropriatestructure, temporality, content,and style when asking patients aboutadherence.34
The structure of a question eitherpromotes or inhibits the amount andkind of information sharing frompatients. Patients will respond toclosed-ended questions with a simpleyes or no, rarely venturing any additionalinformation. Declarative questions(eg, "You take your medication,right?") also squelch patients' propensityto volunteer extensive information.Patients are not being intentionally dishonest;instead they engage in thehuman tendency to be agreeable. (Mylast furnace repairperson used to say,"You change your filter monthly, right?"Of course, I agreed.)
Switching to a subtly interrogative,open-ended question approach thatuses question strings allows collaborationand also permits patients to verbalizeconcerns and beliefs. Pharmacistscan say, "Tell me how you takethis prescription," and then help thepatient see how to improve. The resultshould improve adherence.34
Providers also need to simplify theircommunication. Asking about medicationsby pharmaceutical or tradenames can confuse some patients.Describing tablet or capsule color andsize can prompt better responses,especially for patients with low healthliteracy.35,36 Confrontational communicationstyles will tend to make patientsdefensive and will erode potentialprovider-patient therapeutic alliances(eg, "Didn't I tell you to take it in themorning on an empty stomach?").37,38Providers who insist on communicationthat transfers information to thepatient rather than exchanges informationcollaboratively miss an opportunityto improve adherence.39-41
In addition to communication barriers,patients' beliefs about medication alsomay contribute to problems with communicatingabout medication taking.42Demographics such as age, gender, race,intelligence, level of education, maritalstatus, and social status generally do notcontribute to or affect adherence. Elders' adherence problems usually arerelated more closely to the medicationregimen's characteristics than to ageitself. Limited access to health care,financial problems, and lack of socialsupport can undermine adherence.43
My furnace repairperson cajoled meinto being more adherent to my furnacemaintenance schedule. He pointedout barriers (poor location, dirtyjob); factors that increased my risk ofpoor outcome (multiple animals in thehouse); and the inevitable outcome if Ifailed to adhere (costly furnacerepairs). He taught me ways to remember(put a note in with my bills payable,ask for help from family members).Then, he stuck out his hand to shakeand said, "Promise you'll do better." Weestablished an informal "contract," andmy adherence is better.
Try a similar approach when youcounsel patients about improvingadherence, but realize that the patientswith whom you can expect to see thebest return on investment are thosethat are mildly to moderately nonadherent.Do not expect to changepatients who are completely nonadherentinto adherence stars. Nevertheless,do not let a counseling opportunitypass you by. It may very well bethe one that may promote some positivechange.
Ms. Wick is a senior clinical researchpharmacist at the National CancerInstitute, National Institutes ofHealth, Bethesda, Md. The viewsexpressed are those of the authorand not those of any governmentagency.
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