S. Address Adherence to Therapy

objective

Identify causes of inadequate response to therapy following dose or stepwise titration.

background

Poor adherence can limit the effectiveness of lipid lowering therapies.  In asymptomatic conditions such as dyslipidemia, this can be especially problematic.  The selection of patients, close monitoring, and educational efforts of providers lead to a higher adherence to therapy in clinical trials.  In general practice, long-term adherence to drug therapy is estimated to be only 50 percent.  Adherence to drug therapy should be assessed in any individual taking medications before assuming that a lack of response is attributed to simple inadequacy of the chosen agent.  The NCEP ATP-III guidelines acknowledge the challenge in implementing and maintaining patient adherence to both lifestyle changes and pharmacotherapy regimens.

Factors associated with poor adherence to medication include:

• Number of drugs: Complexity, and frequency of drug administration
• Medication adverse effects: Particularly an issue for niacin and resins, although statins may cause myalgias and nonspecific gastrointestinal symptoms
• Incomplete patient education: Asymptomatic patients may not understand the benefit of medication or need for long-term therapy
• Cost and psychosocial factors: Patients may not be able to obtain medications.

Factors associated with poor adherence to diet and exercise include:

• Incomplete patient effort and self-motivation: Some patients are unable or unwilling to comply with strict dietary changes, such as a TLC diet, and a regular exercise regimen
• Suboptimal social support: Family and lifestyle may not be conducive to strict dietary changes.  Patients may not have access to exercise facilities or safe environment (e.g., safe neighborhood in which to walk)
• Incomplete patient education: Some patients may not have received adequate information because of missed visits or inadequate time for counseling
• Cost: Patients may perceive that dietary interventions increase costs, although this is generally not the case.  Patients unable to walk may not have access to other exercise options (swimming, stationary bike/machines, etc.)

recommendations

1. Adherence to therapy should be assessed at every visit, through history, pill count, and/or administrative records especially if therapeutic goals have not been reached.  [I]
2. Adherence to lipid-lowering medication regimens may be improved by a multi-pronged approach [I] including:

1. Evaluation of medication side effects
2. Simplifying medication regimens to incorporate patient preference
3. Addressing barriers for obtaining the medications (administrative, economic, etc.)
4. Coordination with other healthcare team members to improve monitoring of adherence with prescriptions of pharmacological and lifestyle modification
5. Patient and family education about their disease/treatment regimens
6. Evaluation for depression.
   
   

discussion

Numerous reasons for poor medication adherence have been suggested including long-term therapy, cognitive impairment, number of medications prescribed, frequency of administration, complexity of the drug regimen, cost of medications, side effects, and other factors such as acceptance of the disease, perceived severity, and satisfaction with healthcare providers, etc.(Eraker et al., 1984).  Adherence to medication regimens may also be impacted by patient and/or caregiver education on the disease and its management, education of the healthcare practitioner on patient communication, patient involvement in self-care, and health professional medication monitoring.

It is difficult to apply patterns of medication adherence to various diseases due to different belief models or motivating factors for adherence (e.g., acute life-threatening disease, symptomatic illness vs. asymptomatic condition).  For example, the use of statins in controlled studies such as the Heart Protection Study was high (85 percent) over multiple years (HPS, 2002).  In practice, two-year compliance may be as low as 40 percent in the elderly (Jackevicius et al., 2002; Benner et al., 2002).  Comorbidity of major depression and diabetes is associated with less physical activity, unhealthy diet, and lower adherence to oral hypoglycemic, anti-hypertensive, and lipid-lowering medications.  Adverse effects (more common in individuals on multiple agents), may also affect adherence.