Measurement of medication adherence

MEASUREMENT OF MEDICATION
ADHERENCE
BY: Dr. Vishwas A T L
Assistant Professor
Dept. of Pharmacy Practice
Bharathi College of Pharmacy
Bharathinagara - 571422

CONTENTS
Definitions
Epidemiology
Ways to encourage adherence
Methods for assessment
Role of pharmacist
Conclusion
References

DEFINITIONS
Medication adherence is defined by the World
Health Organization as "the degree to which the person's
behavior corresponds with the agreed recommendations
from a health care provider.
Compliance is the extent to which a patient’s
behavior matches the prescriber’s advice. Compliance
implies patient obedience to the physician’s authority.

EPIDEMIOLOGY
Nonadherence can account for up to 50% of treatment
failures, around 125,000 deaths and up to 25% of
hospitalizations each year in the United States according to a
report in the Annals of Internal Medicine. Typically, adherence
rates of 80% or more are needed for optimal therapeutic
efficacy.
The report estimates that non-adherence costs the U.S.
healthcare system between $100 billion and $289 billion
annually.
According to the Annals of Internal Medicine, 20 to
30 percent of prescription medications are never filled, and
approximately 50 percent of medications for chronic disease
are not taken as prescribed.

Formula for calculation of medication adherence
Percentage adherence =
Total number of actual dose of patient has consumed
last appointment
_________________________________ 100
Total number of calculated dose to be consumed

Ways to Encourage Medication Adherence
 Addressing prescription cost concerns. The patients,
doctors, and pharmacists need to have frank discussions
about any challenges a patient may have affording a specific
course of treatment.
 Improving patient education
 Patients need to understand why they are taking a particular
medication, how they are supposed to take it, and what will
happen if they will stop treatment.
 Exploring creative solutions
 One study in South Africa used text reminders and
“treatment partners” to help encourage medical adherence in
the treatment of serious mental conditions.

METHODS TO MEASURE ADHERENCE
Methods for measuring medication adherence can be
categorized into two basic types:
 Direct measurement.
 Indirect measurement.

DIRECT METHODS
 Direct observed therapy
 Measurement of the level of a drug or its metabolite
in blood or urine
 Detection or measurement of a biological marker
added to the drug formulation in the blood.

Directly Observed Therapy
 It is most accurate method.
 Patients can hide pills in the mouth and then discard
them.
 This method takes place in the presence of
interviewer.

Measurement of the level of a drug or its
Metabolite in Blood or Urine
 Biological assays measure the concentration of a drug,
its metabolites, or tracer compounds in the blood or urine of
a patient. These measures are intrusive and often costly to
administer.
 Patients who know that they will be tested may consciously
take medication that they had been skipping so, the tests will
not detect individuals who have been nonadherent.
 Drug or food interactions, physiological differences, dosing
schedules, and the half-life of the drugs may influence the
results.

Measurement of a Biological Marker
 This method was not suitable for all the medications.
 For instance riboflavin, a biological marker in which
simply nonquantitative for detection. Additionally,
drug-drug interactions and drug-food interactions can
hinder the assay’s accuracy.
 It is difficult to collect the samples.

INDIRECT METHODS
 Patient Interviews
 Patient self reports
 Pill counts, prescription refills
 Assessment of patient’s clinical response, electronic
medication monitors
 Measurement of physiologic markers
 Patient diaries

Patient Interviews
 Interviewing patients by clinicians is generally an easy-to-
use, low-cost subjective method to assess patient’s
adherence.
 Patients can be asked to estimate their own medication-
taking behavior, namely, which percentage of dose that
they may miss within a designated period or the frequency
that they are unable to follow the medication regimen.
 Alternatively, questions can also be based on patient’s
knowledge on the personal prescribed regimen, including
drugs’ name, schedule, and indications.

Patient Self Reports
 Self-reported measures, such as diaries and
questionnaires, are fairly simple to administer. However,
because some patients may be resistant to periodically
answering a series of questions or entering their
medication administration information in a diary on a
regular basis, this may present an obstacle to the
enrollment process.
 Although diaries are less influenced by recall bias,
they have been used as an intervention to improve
adherence.

Pill Counts
 Counting the number of pills remaining in a patient's
supply and calculating the number of pills that the
patient has taken since filling the prescription is the
easiest method for calculating patient medication
adherence.
 This method is simple, it has many disadvantages that
the patients can switch medicines between bottles and
may even discard pills before hospital visits in order to
appear to be following the regimen. Hence, this is not
an ideal measure of adherence.

Prescription Refills
 This method also allows for an evaluation of a large
number of patients over an extended period of time.
However, the adherence value obtained from refill data
does not produce any information on medication
consumption; rather, it solely provides assessment of
acquisition and possession of medication.
 It is assumed that patients administer the medication
between the day of dispensation and the day of the refill.
 Since this method is based on prescription refills of
prescriptions, it is better suited to study chronic rather
than short-term treatment.

Assessment of Patient’s Clinical Response
 The patients’ clinical response can be used as a surrogate
marker of adherence.
 Measurement of the clinical response can be performed during
regular visits to the health care provider and may already
constitute the standard of care for monitoring of the disease
being treated.
 While this method may allow the investigator to capture severe
nonadherence.

Electronic Medication Monitors
 Electronic drug monitors, including the medication event
monitoring system (MEMS), consist of specialized microchips
incorporated into medication bottles that catalogue every opening
of the bottle.
 MEMS offers a precise record of patients’ medication-taking
behavior provided that each bottle-opening truly represents a
single administration and that patients avoid transferring
medications into other containers. These systems are also
expensive and usually require regular downloading of information
directly from the microchip to the compatible software program.

 The Medication Event Monitoring System (MEMS)
manufactured by Aardex Corporation allows the assessment of
the number of pills missed during a period as well as adherence
to a dosing schedule.
MEMS Cream Tube MEMS Pills Bottle

Measurement of Physiologic Markers
• Biomarkers are quantitative measures that allow us to
diagnose and assess the disease process and monitor
response to treatment.
• Blood pressure is used to determine the risk of stroke. It
is also widely known that cholesterol values are a
biomarker and risk indicator for coronary and vascular
disease

Patient-Kept Diaries
 This is the only self-report tool that is consistently
documented with how the patient follows their prescribed
regimen. However, overestimation is very common and
an average of 30% surplus of diary entries has been
shown to occur when comparing with different results
from MEMS data.
 Authors also mentioned other factors that can
contribute to its unreliability, including the inability to
carry out the assessment if the patient does not return the
diary or the reported “false” increase in patient’s
adherence rate from monitoring phase to self-assessment
phase

Scaled Questionnaires
• Morisky et al. (1986) developed a 4-item scaled
questionnaire to assess adherence with antihypertensive
treatment. Thier scale demonstrated acceptable psychometric
properties.
• Li et al. (2005) developed four instruments to measure
antihypertensive medication adherence in a population of
Chinese immigrants in the US. Their measures are culturally
sensitive and demonstrate good reliability.
• The Hill-Bone Compliance to High Blood Pressure Therapy
Scale includes 14 items, 8 of which are directed at assessing
medication taking behavior in hypertensive patients (Hill et
al. 2000).

Morisky scale
It’s used for many different diseases such as hypertension,
hyperlipidemia, asthma, and HIV.
(Please tick Yes No)
1. Do you ever forget to take your (name of health
condition) medicine?
2. Do you ever have problems remembering to take your
(name of health condition) medication?
3. When you feel better, do you sometimes stop taking your
(name of health condition) medicine?
4. Sometimes if you feel worse when you take your (name
of health condition) medicine, do you stop taking it?

Scoring the Morisky Scale
Yes=0 and No=1
• Zero is the lowest level of medication adherence
• 4 is the highest level of medication adherence
Patients scoring 0 or 1 would benefit most
from pharmacist intervention
• Goal: Screen for those in which the pharmacist time
should be spent on enhancing adherence.

ROLE OF PHARMACIST
 Be friendly and approachable to patient.
 Improve patient education.
 Give clear explanation regarding drugs and disease.
 Check the patient understanding.
 Simplify the therapeutic regimen.
 Moniter the side effect.

CONCLUSION
Medication adherence is a complex public
health issue that demands continued progress to
overcome a multitude of patient, provider, and health
system barriers. Pharmacists can take a lead role in
delivering effective patient care services to improve
medication adherence and optimize patient outcomes.

REFERENCES
• P. Michael Ho, Chris L. Bryson and John S. Rumsfeld.
Medication Adherence. AHA journal. 2009; 119(23): 3028-
3035.
• Marie T. Brown and Jennifer K. Bussell. Medication
Adherence: WHO Cares?. Mayo Clin Proc. 2011 Apr; 86(4):
304–314.
• Beena Jimmy and Jimmy Jose. Patient Medication Adherence:
Measures in Daily Practice. Oman Med J. 2011 May; 26(3):
155–159.
• Charlotte A. Kenreigh and Linda Timm Wagner. Medication
Adherence: A Literature Review. Medscape. Oct 12, 2015.

Measurement of medication adherence

Measurement of medication adherence

More Related Content

What's hot

Similar to Measurement of medication adherence

Recently uploaded

Measurement of medication adherence