Objectiveto determine the proportion of patients aged 75 years or older with chronic kidney disease and an estimated glomerular filtration rate <60 mL/min/1.73 m2, for whom at least one medication-related treatment modification was proposed following the structured review.MethodsA single-centre, uncontrolled longitudinal study evaluating a structured medication review and the subsequent implementation of proposed treatment modifications was conducted in patients aged 75 years or older with an estimated glomerular filtration rate below 60 mL/min/1.73 m2. Data was obtained from laboratory systems, medical records, and electronic prescribing. Chronic medication was reviewed using a structured therapeutic appropriateness guide according to renal function. Sociodemographic variables, comorbidity, polypharmacy, need for intervention, and changes made after the treatment modifications were analysed.ResultsAmong the 1,937 patients aged ≥75 years registered at the primary care centre, 178 met the study eligibility criteria based on a recorded eGFR <60 mL/min/1.73 m2. Mean age was 86.2 years, 69.6% were women, and 88.7% were exposed to polypharmacy. At least one medication-related treatment modification was proposed for 111 patients (62.4%), with 215 individual modifications proposed overall. The therapeutic groups with the greatest need for intervention were analgesics and non-steroidal anti-inflammatory drugs, oral antidiabetic agents, and antihypertensive drugs. At follow-up, corresponding prescription changes were observed for 114 of the 215 proposed modifications (53.0%). At the patient level, at least one corresponding prescription change was observed in 64 of the 111 patients for whom one or more modifications had been proposed (57.7%).ConclusionThe structured medication review identified a substantial number of potential medication-related problems and proposed treatment modifications in older patients with reduced renal function. Approximately half of the proposed modifications were observed in the electronic prescription at follow-up. However, because the study lacked a control group, the extent to which these changes were attributable to the structured review cannot be determined.