The impact of pharmacogenetic-informed care on medication adherence and psychological factors associated with adherence: A narrative review.

Improvement in medication adherence is often proposed as a potential advantage of pharmacogenetic-guided prescribing over a traditional one-size-fits-all approach. This paper provides a review of the published literature and presents the findings of studies that measure adherence to medication as an outcome of pharmacogenetic-informed care, or that measure the impact of pharmacogenetic-informed care on psychological factors that are associated with medication adherence. Adherence-related psychological factors are mapped to the Theoretical Domains Framework (TDF) to provide insight into how participants interact with pharmacogenetic-informed care as an intervention and to consider this in the context of medication adherence. A total of 23 studies were included, with 10 quantitative studies measuring medication adherence outcomes associated with pharmacogenetic-informed care. Five of these studies found a statistically significant improvement in adherence in the pharmacogenetic-tested group, two reported a small but non-significant trend, and three showed no difference. Additionally, 13 studies examined the impact of pharmacogenetic-informed care on psychological factors related to adherence. These factors were mapped to 10 TDF domains: knowledge (8 studies); social/professional role and identity (1); beliefs about capabilities (2); optimism (4); beliefs about consequences (10); intentions (5); goals (1); memory, attention and decision processes (7); social influences (4); and emotion (8). The findings suggest that although the evidence for pharmacogenetic-informed care improving medication adherence is mixed and limited, pharmacogenetic-informed care appears to positively influence psychological factors that may support adherence. These include improving knowledge, supporting decision-making and generally being perceived as a positive experience by patients.