Evaluation of Dose Adjustment in Patients With Renal Impairment at Muhimbili National Hospital in Tanzania.

Background: The burden of renal diseases is increasing in developing countries like Tanzania. Drug accumulation exposes patients with renal impairment to drug toxicity that may lead to adverse drug reactions, poor adherence to treatment, and increased healthcare costs. There is limited information on the appropriateness of dosage regimen adjustment for patients with renal impairment, particularly in developing countries such as Tanzania. This study aimed to investigate the appropriateness of drug dosing in hospitalized patients with renal impairment in Tanzania. Methods: This was a retrospective cross-sectional study. It was conducted between November 2019 and April 2020 amongst hospitalized patients at Muhimbili National Hospital. All enrolled patients had serum creatinine levels ≥1.2 mg/dL and taking at least one drug requiring dosage regimen adjustment. Creatinine clearance was calculated from patient serum creatinine using the Cockcroft-Gault equation. Drug dosing appropriateness was determined by comparing the current practice with tertiary references. The relationship between the patient's baseline characteristics and the rate of dosage regimen adjustment was determined using the X² test. Univariate and multivariate logistic regression analysis evaluated the predictors of dosing adjustment. Results: Most of the enrolled patients, 269 (98.9%) had comorbidities. Of the medication orders included in the final analysis, 372 (27%) needed dosage regimen adjustment. Out of the 372 medication orders, not adjusted were 168 (45.2%), inappropriately adjusted 105 (28.2%), and appropriately adjusted were only 99 (26.6%). In this study, 212 (77.9%) patients received at least one drug with an incorrect dosage regimen. Females and those with level 4 renal impairment patients were more likely to have their doses appropriately adjusted compared to their counterparts. Conclusions: In this study, about three-quarters of the patients received at least one drug with an incorrect dosage regimen. Thus, appropriate measures such as the availability of national guidelines and clinical decision support systems for drug dosing adjustment in patients' renal impairment should be in place.