Poor adherence to medical treatment severely compromises patient outcomes and increases patient mortality. According to the WHO, improving adherence to medical therapy for conditions of hypertension, hyperlipidemia, and diabetes would yield very substantial health and economic benefits. The multi-factorial causes of decreased compliance must be understood to improve medication adherence.
The WHO classifies these factors into five categories:
socioeconomic factors, factors associated with the health care team and system
in place, disease-related factors, therapy-related factors, and patient-related
factors. In broader terms, these factors fall into the categories of
patient-related factors, physician-related factors, and health system/team-building-related
factors.
Patient-Related Factors
• The most common reasons given by patients for not
taking their medications are forgetfulness (30%), other priorities (16%),
deciding to omit a dose (11%), lack of information (9%), and emotional reasons
(7%); 27% of patients give no reason.
• Several patient-related factors including; lack of
understanding of their disease, lack of involvement in the treatment
decision–making process and suboptimal medical literacy, contribute to
medication non-adherence.
• Factors that are associated negatively with
adherence include; increased complexity or duration of a medication regimen, side
effects, very old age, extreme poverty,
social isolation and psychiatric diagnoses, especially paranoia; a study
on adherence in HIV-positive individuals, which included these patient-level
factors, found that older HIV-positive patients with neurocognitive impairments
or drug problems were at an increased risk of suboptimal medication adherence
when compared to their younger counterparts.
• The risk of non-adherence is especially high when
multiple predisposing factors converge such as; cognitive impairment and the
use of numerous medications for multiple chronic conditions in the
elderly.
• Specific factors identified as barriers to
medication adherence among inner-city patients with low socioeconomic status
were high medication costs, lack of transportation, poor understanding of
medication instructions, and long wait times at the pharmacy. A lack of family
or social support is also predictive of non-adherence, as is poor mental health.
Table.1:
Patient's Understanding of Their Medication and Adherence
|
Medication
Knowledge |
Patients
Answering Correctly (%) |
|
Dose |
65.6 |
|
Frequency |
49.2 |
|
Indication |
19.7 |
Physician Related Factors
• Not only do physicians often fail to recognize
medication non-adherence in their patients, but they may also contribute to it
by prescribing complex drug regimens, failing to explain the benefits and
adverse effects of medication effectively, and inadequately considering the
financial burden to the patient.
• Ineffective communication between the primary care physician
and the patient with a chronic disease further
compromises the patient's understanding of his or her disease, its potential
complications, and the importance of medication adherence.
• Failing to elicit a history of alternative, herbal
or supplemental therapies from patients is another source of ineffective
communication.
• Communication among physicians is often insufficient
and may contribute to medication non-adherence. Direct communication between
hospitalists and primary care physicians occurs in less than 20% of
hospitalizations and discharge summaries are available at less than 34% of
first post-discharge visits.
• Inadequate communication between physicians,
hospitalists, primary care physicians, and consultants also contributes to medication
errors and potentially avoidable hospital readmissions.
Health System/Team Building-Related Factors
• Fragmented healthcare systems create barriers to
medication adherence by limiting the healthcare coordination and the patient’s
access to care.
• Prohibitive drug costs or copayments also contribute
to poor medication adherence.
• Health information technology is not widely
available, preventing physicians from easily accessing information from
different patient care-related venues, which in turn compromises patient care,
timely medication refills, and patient-physician communication.
• In an overtaxed healthcare system in which
clinicians see a large volume of patients without resources to meet individual
patient needs, the amount of time a clinician spends with patients may be
insufficient to properly assess and understand their medication-taking
behaviors.
• This lack of time may preclude engaging the patient
in a discussion on the importance of medication adherence and strategies to
achieve success.
The World Health Organization (WHO) breaks medication
adherence into 5 interacting dimensions. Below is a table showing some of the
possible reasons that contribute to poor adherence per each of the 5
interacting dimensions.
Table.2:
Possible Reasons That Contribute to Poor Adherence
