Significant proportions of individuals with psoriasis who are prescribed self-administered systemic therapies report both intentional and nonintentional nonadherence with their treatment regimens, according to the results of the recent Investigating Medication Adherence in Psoriasis study published in the Journal of Investigative Dermatology.

Investigators in the study evaluated real-world levels of self-reported nonadherence with conventional and biologic systemic therapies for psoriasis, assessing the psychological and biomedical factors linked with nonadherence by means of multivariable analysis. Latent profile analysis was used to examine whether patients with psoriasis can be categorized into groups with similar medication beliefs and profiles.

When nonadherence is intentional, patients make a deliberate decision not to follow a prescribed medication regimen (eg, altering the dose, timing, or frequency of their systemic therapy). In contrast, when nonadherence is unintentional — for example, forgetting to use a prescribed medication — it is often associated with the strength of a patient’s routine or habit for taking his or her medication.

A total of 811 patients were enrolled in the study, with 35.3% (286 of 811) in the conventional cohort (includes methotrexate, cyclosporine, and acitretin, and fumaric acid esters) and 64.7% (525 of 811) in the biologic cohort (includes adalimumab, ustekinumab, and etanercept). Of the participants, 617 were using a self-administered systemic therapy. Overall, 22.9% of patients were classified as being nonadherent (12% intentional and 10.9% unintentional). Patients who were being treated with an oral conventional systemic agent were significantly more likely to be nonadherent to their medication compared with etanercept– or adalimumab-treated patients (29.2% vs 16.4%, respectively; P ≤.001).

Overall, all groups felt strongly about their need for therapy but differed in their levels of medication concerns. Group 1 (comprising 26.4% of the sample) reported the strongest concerns, followed by group 2 (61% of the sample) and group 3 (12.6% of the sample), which reported the weakest concerns.

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Weaker medication-taking routine or strength of habit was linked with unintentional nonadherence (odds ratio 0.92; 95% CI, 0.89-0.96; P <.05). Receiving a systemic therapy (OR 3.21; 95% CI, 1.54-6.67; P <.05), having strong medication concerns (OR 2.27; 95% CI, 1.16-4.47; P <.05), having weaker routine/habit for taking systemic therapy (OR 0.95; 95% CI, 0.920.98; P <.05), and a longer treatment duration (OR 1.04; 95% CI, 1.02-1.06; P <.05) were all factors significantly associated with intentional nonadherence.

The investigators concluded that medication beliefs and habit strength are modifiable targets for strategies to improve adherence among patients with psoriasis. This study highlights the need to evaluate medication adherence when determining which factors influence treatment response among this patient population.

Reference

Thorneloe RJ, Griffiths CEM, Emsley R, Ashcroft DM, Cordingley L; BADBIR and PSORT study groups. Intentional and unintentional medication non-adherence in psoriasis: the role of patients’ medication beliefs and habit strength [published online November 25, 2017]. J Invest Dermatol. doi: 10.1016/j.jid.2017.11.015