Dual trajectories of polypharmacy and medication regimen complexity index in people living with HIV in Spain.

Background: Polypharmacy, using 6 or more medications, may increase the risk of high medication regimen complexity index (MRCI). We aimed to identify the interrelationship between trajectories of polypharmacy and MRCI.

Methods: People living with HIV (PLWH) (aged ≥18) were included in from 2010 to 2021. Group-based trajectory modeling (GBTM) was used to identify polypharmacy trajectories and the complexity index of the medication regimen and the dual GBTM to identify their interrelationship.

Results: In total, 789 participants who met the eligibility criteria were included in the study, with a median age of 47 years. GBTM analysis was used to reveal latent polypharmacy trajectories among PLWH. The findings disclosed four distinctive trajectories, with the majority (50.8%) of the PLWH falling into the 'low increasing' trajectory. Furthermore, GBTM identified 2 trajectories characterized by high MRCI, and a substantial proportion (80.2%) was assigned to the 'slightly increasing low' trajectory group. The study revealed that younger age (<50 years) was a significant predictor of membership in the 'consistently low' trajectory, while male gender was associated with the groups of 'low increasing' and 'moderately decreasing' polypharmacy trajectory.

Conclusions: GBTM failed to discern a discernible interrelationship between polypharmacy and the high MRCI. It is imperative to undertake future studies within this research domain, considering potential effect modifiers, notably the specific type of concomitant drug. This approach is crucial due to the outcomes induced by both polypharmacy and the magnitude of the pharmacotherapeutic complexity in PLWH.