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

Effect of returning a pharmacogenetic result on the psychological determinants of adherence, analysed with the Theoretical Domains Framework.

Improved adherence is often put forward as a benefit of pharmacogenetics-guided prescribing, without that claim having been examined systematically. This narrative review brings together 23 studies measuring either adherence itself or the psychological factors associated with it, the latter mapped to the Theoretical Domains Framework. Among the ten quantitative studies assessing adherence, five report a statistically significant improvement in the tested group, two a small non-significant trend, and three no difference. The remaining thirteen studies cover ten domains of the framework, the most represented being beliefs about consequences (10 studies), knowledge (8), emotion (8) and memory, attention and decision processes (7). The authors conclude that evidence for an adherence gain remains mixed and limited, whereas the effect on psychological determinants — knowledge, decision support, a positive experience of testing — appears more consistent.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

Five positive studies out of ten, in a narrative review with no registered protocol and no risk-of-bias assessment, do not amount to a body of evidence: this is exactly the configuration in which publication bias produces an apparent majority. The value of this work is to remove adherence from the list of benefits one can promise in clinic when offering genotyping — the justification remains safety and efficacy, not treatment fidelity. One hypothesis deserves proper testing: if the test improves understanding and the experience of treatment without improving measured adherence, the adherence measure itself may be the problem.

Analysis by Dr Thibaut Benquey