Supplementary Material for: Navigating Drug Related Problems (DRPs) in Hemodialysis (HD) Patients Across Dual Healthcare Systems: Bridging the Gaps for Optimal Medication Safety

ABSTRACT
Background: Drug-related problems (DRPs) are common in hemodialysis (HD) patients but the impact of different healthcare delivery models on DRP prevalence, characteristics and medication-related outcomes remains underexplored.

Objective: This study aimed to investigate and compare DRP prevalence and characteristics among HD patients across two healthcare settings.

Methods: This prospective cross-sectional study involved adult chronic HD patients from hospital-based (with pharmacist-led medication management program) and non-hospital-based (without) ambulatory centers. Patients on temporary HD or who had language barrier were excluded. Clinical characteristics and DRP data, identified through structured clinical review and classified using Pharmaceutical Care Network Europe (version 9.0), were analyzed using descriptive statistics, Mann-Whitney U, and chi-square tests.

Results: A total of 76 hospital-based and 149 non-hospital-based patients were recruited with significant differences between settings observed. Non-hospital-based patients showed a markedly higher DRP burden (n=145 [97.7%], 4.6 DRPs/patient) compared to hospital-based patients (n=42 [55.3%], 0.8 DRPs/patient). DRPs categorized as “Other” predominated the non-hospital-based group (n=345 [50.2%], z=+5.296, p< .001, Bonferroni-adjusted) and were driven by non-clinical factors such as patient-related, patient transfer-related, and work processes (z=+5.904), with the majority of the DRPs associated with antihypertensive agents (n=145, 21.0%). Conversely, treatment-effectiveness DRPs were significantly more prevalent than expected in the hospital-based group (n=45 [67.2%], z=+5.159, p<.001, Bonferroni-adjusted) and were primarily due to clinical factors such as drug selection, drug form, dose, and duration, that had direct effects on treatment (z=+5.904). Phosphate binders (n=21, 31.3%) were the most common medication class associated with DRPs in this group.

Conclusion: This study demonstrates that variations across healthcare settings, compounded by frequent transitions of care significantly influenced DRP prevalence and characteristics among the highly vulnerable HD patients. Structured support services such as pharmacist-led medication management program play a critical role in mitigating these risks and supporting patients through complex treatment pathways. These findings underscored the importance of addressing both system-level disparities and patient-level challenges, where future research should adopt mixed-method approaches to uncover the contextual drivers of DRPs and guide the development of sustainable, pharmacist-integrated care models that would improve medication safety across diverse dialysis settings.