Background and importance Adherence to medication is crucial to achieve outcomes in health.

Aim and objectives To assess annual adherence to medications in the outpatient pharmacy during 2019.

Material and methods We selected all patients on chronic therapy in our outpatient pharmacy, and the medication possession rate (MPR) during 2019 was measured based on the pharmacy refill record.

To assess the relationship between variables and adherence, the non-parametric Wilcoxon signed rank test and the Kruskal–Wallis test were applied. A p value <0.05 was deemed to be statistically significant.

Results 131 patients on chronic treatment were selected. Mean age of the study group was 55.8 years (SD 16.9; range 17–92) and 51.2% were women. 51.2% of patients were on adalimumab, 7.6% baricitinib, 6.1% colistimetato and 4.6% etanercept, certolizumab and secukinumab. Patients were treated for rheumatic arthritis (34.4%), axial spondylitis (15.3%), psoriatic arthritis (14.5%) and Crohn’s disease (12.2%). For route of administration, the principal route was the subcutaneous route (76.3%), oral in 16.8% and inhalation in 6.9%. Mean MPR in the study population was 96.1% (SD 9.2%) and the median days to assess adherence was 289.2 (IQR_25–75 223–360). The number of patients with MPR <90% was 11 and only 7 patients had an adherence level <80%.

We indicated in the patient medical record any adherence problems in order to assess adherence and improve it at next visit or appointment. We found no relationship between adherence and gender (97.2% in women versus 94.9% in men, p=0.33) or age (p=0.81). Mean adherence regarding route of administration was 90.3% (SD 18.8%; n=9) for the inhalation route, 95.9% (SD 8.7%; n=100) for the subcutaneous route and 99.3% (SD 3%; n=22) for the oral route, with a statistical difference between them (p=0.0064). This difference was confirmed between the inhaled and oral routes (p=0.002) and subcutaneous and oral routes (p=0.004).

Conclusion and relevance The adherence level was high in our population and only 11 patients had an adherence level <90%. The route of drug administration appeared to be a determinant for adherence, especially for inhaled therapy.

Conflict of interest No conflict of interest