Medication Adherence: Taking Special Measures

Guido R. Zanni, PhD
Published Online: Monday, November 12, 2012
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Foster a therapeutic partnership by understanding patients' reasons for nonadherence.
Medication adherence—defined as patients taking medications as prescribed by health care providers—optimizes health outcomes and decreases health costs.1 “Medication compliance” is a term that is no longer widely used, because it suggests that patients are passive participants following orders. Adherence, on the other hand, connotes that patients are active participants in the therapeutic alliance.

Several categories comprise medication nonadherence: delaying or failing to fill prescriptions; cutting dosages or reducing the frequency of administration; taking incorrect doses or taking them at the wrong time; using outdated or improperly stored medications; improperly using administration devices (eg, inhalers); and taking medications with prohibited foods or other medications.2 Failing to fill a prescription, omitting doses, or delaying doses are the most common deviations from medication regimens.1

What is acceptable adherence? Many researchers use an 80% adherence rate, whereas others use 95%. Acceptable adherence rates vary by disease. When treating HIV, for example, maximum clinical outcomes are achieved with 95% adherence; adherence less than 85% is linked to HIV drug resistance.3 Also, studies demonstrate that many clinical outcomes continue to improve when adherence exceeds 80%.4

Nonadherence is linked to disease worsening, increased mortality, and increased health costs. Adherence is especially problematic for chronic conditions (Sidebar1,3-10).5

Measuring Adherence

Both direct and indirect methods are used to measure adherence. Direct methods include observation, serum drug concentration, and biochemical assays. Although direct methods offer increased accuracy, they are often impractical and costly to use. Indirect methods of measuring adherence include pharmacy refill records, patient self-reports, clinical response, and electronic monitors.4,8 Pill counts, self-reports, and prescription refills are the most common methods employed, but studies demonstrate that these overestimate adherence.4,8

Counseling

Although studies report that 40% to 50% of patients are nonadherent, only 8% acknowledge nonadherence.9 The ability of physicians to recognize adherence is poor, leaving others, especially pharmacists, with the responsibility of counseling on the importance of adherence.1,11 Effective counseling begins with understanding nonadherence’s multi-faceted causes, which include1,4,5:
  • Management of complex/multiple medications
  • Inability to understand regimen
  • Forgetting to take medication (most common cause)
  • Unpleasant side effects and poor tolerability
  • Depression
  • Poor provider-patient relationship
  • No discernible impact on patients’ asymptomatic conditions
  • Prescription cost
Patient fears of side effects are potent contributors to nonadherence. For example, a Harris poll found that 94% of patients discontinued a medication after experiencing a side effect.12 No single effective strategy exists to improve adherence; multiple interventions work best, especially self-monitoring, simplified dosing, and direct pharmacy involvement (Table1,3,4,13-15 ).9



Technology to the Rescue

Forgetfulness is a frequent cause of nonadherence by patients. To improve adherence, providers have turned to technology-based interventions to remind patients to take their medication. Technology-based reminders, including e-mails, timed telephone calls, text messages, and electronic reminder devices that produce audio or visual cues, have positive effects, especially when combined with counseling.16

Recently, the FDA approved a sensor that can be embedded in a pill, which relays data when stomach fluid activates the device, sending signals to a remote device, allowing for more accurate information on adherence.17 In terms of more commonly used forms of technology, text message reminders are especially effective.6,18 Despite the boost these interventions offer, adherence declines with the withdrawal of reminders.19

Final Thought

Up to 76% of adults view pharmacists positively as specialized providers with medication management expertise; yet only 25% have regular conversations with their pharmacists.20 As credible specialists, pharmacists should take every opportunity to stress the importance of adherence and its impact on clinical outcomes.


Dr. Zanni is a psychologist and health-systems consultant based in Alexandria, Virginia

 
References

1. Osterberg L, Blaschke T. Adherence to medication. N Engl J Med. 2005;353:487-497.
2. Fischer MA, Stedman MR, Lii J, et al. Primary medication non-adherence: analysis of 195,930 electronic prescriptions. J Gen Intern Med. 2010;25:284-290.
3. Would Health Organization. Adherence to long-term therapies: evidence for action. http://apps.who.int/medicinedocs/pdf/s4883e/s4883e.pdf. Published 2003. Accessed September 10, 2012.
4. Ho PM, Bryson CL, Rumsfeld JS. Medication adherence: its importance in cardiovascular outcomes. Circulation. 2009;119:3028-3035.             
5. Bosworth H; Duke University Medical Center, National Consumers League. Medication adherence: making the case for increased awareness. http://scriptyourfuture.org/wp-content/themes/cons/m/Script_Your_Future_Briefing_Paper.pdf. Accessed September 14, 2012.
6. Linn AJ, Vervloet M, van Dijk L, et al. Effects of eHealth interventions on medication adherence: a systematic review of the literature. J Med Internet Res. 2011;13:e103.
7. Cutler DM, Everett W. Thinking outside the pillbox--medication adherence as a priority for health care reform. N Engl J Med. 2010;362:1553-1555.
8. Hiligsmann M, Boonen A, Rabenda V, Reginster JY. The importance of integrating medication adherence into pharmacoeconomic analyses: the example of osteoporosis. Expert Rev Pharmacoecon Outcomes Res. 2012;12:159-166.
9. Zanni G. Counseling for improved medication adherence. Pharmacy Times. 2011;77(9):66-69.
10. Bruce JM, Lynch SG. Multiple sclerosis: MS treatment adherence--how to keep
patients on medication? Nat Rev Neurol. 2011;7(8):421-422.
11. Meddings J, Kerr EA, Heisler M, Hofer TP. Physician assessments of medication adherence and decisions to intensify medications for patients with uncontrolled blood pressure: still no better than a coin toss. BMC Health Serv Res. 2012;12:270.
12. 1.Harris Interactive. Large numbers of people are not very confident in their own knowledge and the safety of prescription medications and this often leads to non-adherence. Healthcare News. April 18, 2007;1-5. www.harrisinteractive.com/NEWS/allnewsbydate.asp?NewsID=1206. Accessed September 14, 2011.
13. Elstad E, Carpenter DM, Devellis RF, Blalock SJ. Patient decision making in the face of conflicting medication information. Int J Qual Stud Health Well-being. 2012;7:1-11.
14. Dupclay L, Eaddy M, Jackson J, Raju A, Shim A. Real-world impact of reminder packaging on antihypertensive treatment adherence and persistence. Patient Prefer Adherence. 2012;6:499-507.
15. Sewell K, Andreae S, Luke E, Safford MM. Perceptions of and barriers to use of generic medications in a rural African American population, Alabama, 2011. Prev Chronic Dis. 2012;9:E142.
16. Saberi P, Johnson MO. Technology-based self-care methods of improving antiretroviral adherence: a systematic review. PLoS One. 2011;6(11):e27533.
17. Dey E. A pill that treats and tells. Reuters News. www.reuters.com. Accessed August 27, 2012.
18. Vervloet M, Linn AJ, van Weert JC, et al. The effectiveness of interventions using electronic reminders to improve adherence to chronic medication: a systematic review of the literature. J Am Med Inform Assoc. 2012;19:696-704.
19. Christakis DA, Garrison MM, Lozano P, et al. Improving parental adherence with asthma treatment guidelines: a randomized controlled trial of an interactive website. Acad Pediatr. 2012;12:302-311.
20. RxAlly. New survey finds more U.S. adults trust the Internet than trust their pharmacist to help with health care decisions. www.harrisinteractive.com/vault/2012_RxAlly_InternetVsPharmacists.pdf. Accessed October 12, 2012.
 






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