Background and importance Complex medication regimens (MR) are associated with worse treatment adherence. The Medication Regimen Complexity Index (MRCI) is a validated tool used to quantify complexity of MR and it is the sum of the score in three sections: dosage forms (A), dosing frequency (B) and additional directions (C).

Aim and objectives To assess the relative MR complexity among solid organ transplant patients (SOT; kidney, heart, lung and liver) in a tertiary hospital through the validated MRCI Spanish version.

Material and methods Transplant patients who collected medication in the Hospital Pharmacy between January and March 2021 were selected. A total of 40 patients (10 per transplant) were chosen randomly through Excel, and a macro with a template of MCRI was created. The qualitative variables were age, sex and type of transplant; the quantitative ones were months from transplant, the total amount of medications, sections A, B, C and total MRCI. All prescribed medications documented in medical records at the hospital ambulatory clinics and the electronic medication list were included. Patients were excluded if they were followed up in other hospitals, had died or MR dosage or frequency was missed/unclear. Subgroup analysis was made to assess MRCI among the type of transplants through ANOVA. All data analysis was made with SPSS version 23, with a <0.05 significance level and a confidence interval of 95%.

Results Sample median age was 56.6±14.7 years (95% CI 51.9 to 61.3), a 40% (16/40) were women, median of time from trasplant was 92.7±69.9 months (95% CI 70.4 to 115.0) and number of medications 11.1±4.6 (95% CI 9.6 to 12.6). Subgroup median MCRI were 23.3±10.2 (kidney; 95% CI 16.0 to 30.5), 46.2±12.8 (lung; 95% CI 37.1 to 55.3), 28.5±11.1 (heart; 95% CI 20.6 to 36.4) and 18.7±5.4 (liver; 95% CI 14.8 to 22.5). Section B was the greatest contributor to MCRI (16.6±8.2; 95% CI 14.0 to 19.2), followed by C (6.6±4.3; 95% CI 5.2 to 7.9) and A (5.7±3.7; 95% CI 4.5 to 6.9). Tukey test showed a statistically significant MCRI in lung transplant with p<0.001 when compared to kidney and liver transplants, and p=0.002 compared to heart transplant.

Conclusion and relevance The medication regiment of our sample was more complex in lung patients than in any other SOT, therefore these patients could benefit more from pharmaceutical interventions. Further studies with larger samples are required to confirm differences among kidney, liver and heart transplants.

Conflict of Interest No conflict of interest