Factors associated with medication non-adherence identified for PD

By Ingrid Grasmo, medwireNews Reporter

Depression and complex drug regimens are among the factors associated with non-adherence to medication in patients with Parkinson's disease (PD), show the findings of a systematic review.

Previous research has shown that as few as 10% of PD patients fully adhere to treatment regimens, which can result in substantial motor fluctuations and increased risk for worsening symptoms.

David Daley (University of East Anglia, Norwich, UK) and colleagues say identification of factors related to non-adherence to PD medications could allow healthcare professionals to identify at-risk patients and facilitate the development of targeted interventions.

"Targeted, patient-centered interventions should be investigated to establish if addressing factors in PD leads to greater adherence," say the researchers in Parkinsonism and Related Disorders.

Their analysis of six studies reporting data on medication non-adherence in a total of 772 individuals with idiopathic PD revealed 11 factors associated with medication non-adherence.

Patients included in the studies were aged on average 62 years, had a mean disease duration of 7.4 years, and took approximately six prescriptions daily (average of two anti-parkinsonian drugs with 4.6 daily doses).

Depression was shown to be the strongest factor associated with medication non-adherence in three studies (20-40% reported levels), followed by poor clinical control or quality of life (13-40%), and complex drug regimens (13-20%).

The researchers say the association between depression and non-adherence replicates findings in other chronic conditions and comment: "As depression affects up to 40% in PD, often presenting early, one sensible approach is to be watchful for depressive symptoms and consider targeted intervention which may prevent non-adherence from developing."

Although poor clinical control and quality of life were associated with poor medication adherence, the researchers note that it is more likely that non-adherence is the causative factor.

Other identified factors for poor medication adherence included younger age or longer disease duration, impaired cognition, poor knowledge of the condition and low educational status, risk behaviors such as novelty seeking and alcohol abuse, not living with a partner, low income, male gender, and maintaining employment.

The researchers say it is important for clinicians to acknowledge that the desire to maintain employment can drive patients to manipulate their dose in order to maintain performance. They recommend that physicians collaborate with patients through shared decision-making to maximize adherence.

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