Impact of clinical pharmacist interventions on drug-related problems in hospitalised patients with renal dysfunction: a quasi-experimental study

Patients with renal dysfunction are highly susceptible to drug-related problems (DRPs) due to altered pharmacokinetics and polypharmacy. Clinical pharmacists(CP) play a key role in optimising pharmacotherapy and preventing medication errors in this vulnerable population. To evaluate the prevalence of DRPs in patients with renal dysfunction and to compare the effectiveness of a stepwise clinical pharmacy model—transitioning from passive education (Phase 2) to active multidisciplinary integration (Phase 3)—in optimizing medication safety within a Turkish tertiary-care setting. This prospective, quasi-experimental study was conducted in the Internal Medicine Ward of a tertiary-care hospital in Istanbul, Türkiye, between November 2021–2022. The study included adult patients(≥ 18 years) with estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 and at least one medication requiring renal dose adjustment. Three consecutive study phases implemented: observation, education, and intervention. DRPs were identified and classified using the Pharmaceutical Care Network Europe (PCNE) V9.1 classification system. CP interventions were documented, and their acceptance and outcomes were evaluated. A total of 160 patients were included (mean age 74.5 ± 10.1 years). The prevalence of DRPs decreased progressively across the three phases (238, 195, and 169 DRPs, respectively). DRPs associated with renal dysfunction declined significantly from 61.0% to 38.0% of patients (p = 0.046). The most frequent categories were treatment safety (≈70%) and inappropriate drug selection or dosing. In the intervention phase, 47.3% of identified DRPs received active pharmacist interventions, of which 98.7% were accepted and 91.7% fully implemented. Our results demonstrates that while passively educating the medical team provides limited benefit, the active integration of CP into multidisciplinary care is essential for significantly reducing DRPs and improving medication safety in patients with renal dysfunction. The exceptionally high acceptance of these interventions underscores the critical value of real-time, collaborative pharmaceutical care in optimising renal pharmacotherapy.