Patient Medication Adherence

 

MEDICATION ADHERENCE

Definition

The World Health Organization defines medication adherence as:
“The extent to which a person’s behavior in taking medication corresponds with the agreed recommendations from a healthcare provider.”

Key Concepts

Adherence vs Compliance

• Compliance: Passive following of doctor’s orders
• Adherence: Active, agreed participation between patient and healthcare provider

Concordance

• A modern concept emphasizing shared decision-making between patient and prescriber

Types of Medication Non-Adherence

1. Primary Non-Adherence

• Patient does not fill or obtain the prescription

2. Secondary Non-Adherence

Occurs when the patient gets the medication but does not use it properly.

a) Intentional Non-Adherence

• Patient knowingly deviates from instructions
• Examples:
• Taking fewer/more doses
• Stopping medication when symptoms improve
• Using medication with contraindicated foods/drugs
• Improper use of devices (e.g., inhalers)

b) Unintentional Non-Adherence

• Patient unintentionally fails to follow regimen
• Causes:
• Forgetfulness
• Misunderstanding instructions
• Cognitive impairment

Classification Based on Extent of Adherence

Category	Definition
Adherent	Takes > 80% of prescribed doses
Partially adherent	Takes 70–80% of doses
Non-adherent	Takes < 70% of doses

Intelligent Non-Adherence

• Term coined by Weintraub
• Patient stops medication due to adverse effects (e.g., nausea, vomiting, gastric irritation)
• If condition improves after stopping → termed intelligent non-adherence

Clinical Situations Requiring High Adherence

• Metabolic disorders
• e.g., Insulin (Diabetes), Thyroxine deficiency
• Chronic diseases
• Hypertension
• Diabetes mellitus
• Required to prevent complications and disease progression

Important Concept

👉 “Drugs do not work if patients do not take them.” — Everett C. Koop

Quick Revision Tips (Exam-Oriented)

• 2 Types: Primary & Secondary
• Secondary → 2 Types: Intentional + Unintentional
• Cut-offs:

o   80% = Adherent

• 70–80% = Partial
• <70% = Non-adherence

3.     Diseases requiring constant plasma drug levels

• e.g., Epilepsy (to prevent breakthrough seizures)

4.     Chronic infectious diseases of public health importance

• Tuberculosis
• Hepatitis
• HIV infection

Required Level of Adherence

·        > 90% adherence is generally required for optimal therapeutic outcomes

·        In HIV infection:

• < 90–95% adherence →
• Increased viral replication
• Poor clinical outcomes
• Development of drug-resistant strains

·        In hypertension:

• High adherence (>90%) →
• Reduced ischemic heart disease
• Reduced stroke mortality

Consequences of Medication Non-Adherence

Impact on Patient & Healthcare System

• Poor health outcomes
• Increased hospital visits and healthcare utilization
• Higher healthcare costs

Disease-Specific Impact

·        Chronic diseases affected:

• Hypertension
• Diabetes mellitus
• Ischemic heart disease
• Asthma

·        Leads to:

• Treatment failure
• Disease recurrence
• Complications

Example: Tuberculosis

• Caused by Mycobacterium tuberculosis
• Non-adherence leads to:
• Delayed sputum conversion
• 5–6× higher relapse rates
• Development of drug-resistant TB strains

Quality of Life

• Non-adherence → ↓ Quality of life
• Good adherence → ↑ Improved quality of life

Factors Affecting Medication Adherence

(According to World Health Organization)

1. Social & Economic Factors

• Low health literacy
• Lack of social support
• Unstable living conditions
• Busy schedules
• Poor access to healthcare/pharmacy
• High cost of medications
• Cultural beliefs and misconceptions

2. Healthcare System Factors

• Poor patient–provider relationship
• Inadequate communication
• Lack of patient education
• No proper follow-up
• Poor continuity of care

3. Condition-Related Factors

• Symptom improvement → patient stops drugs
• Depression → lack of interest
• Psychiatric illness → forgetfulness

4. Therapy-Related Factors

• Complex regimens
• Special techniques (inhalers, injections)
• Long duration
• Frequent changes in therapy
• No immediate benefit
• Side effects
• Lifestyle restrictions

5. Patient-Related Factors

• Sensory impairment (vision/hearing)
• Cognitive impairment
• Poor mobility
• Swallowing difficulty
• Lack of knowledge
• Fear of adverse effects
• Stress, anxiety, anger
• Low motivation

Formula for Medication Adherence

%Adherence = Total no. of Actual doses the patient has consumed since last appointment  ×100

 /Total number of calculated doses to be consumed  

Role of Pharmacist in Improving Adherence

Key Responsibilities

• Identify barriers to adherence
• Provide patient counseling
• Educate about disease and medication benefits
• Address fear of adverse effects
• Improve patient confidence and motivation
• Help integrate medication into daily routine

Important Insight

• Many patients lack belief in medication benefits
• Doctors often prescribe without detailed counseling
• Pharmacists bridge this gap through effective communication

Key Points (Exam Revision)

• >90% adherence needed for best outcomes
• Non-adherence → treatment failure + resistance
• TB & HIV → high public health impact
• 5 major factors affect adherence (WHO classification)
• Pharmacist = key role in counseling & behavior change