Renal outcomes of diabetic patients treated with combination therapy of ACE inhibitors plus either thiazide diuretics or calcium channel blockers: comparative retrospective cohort study in Northwestern Ethiopia

OBJECTIVE: The study determined the comparative renal functions on patients with diabetes treated with ACE inhibitors (ACEIs) plus either thiazide diuretics or calcium channel blockers (CCBs) in Northwestern Ethiopia. DESIGN: Retrospective cohort study design was employed to collect the data from medical records of patients with diabetes followed for 1–5 years (N=404). SETTING: The medical records of patients in chronic diabetic follow-up clinics of the hospital. PARTICIPANTS: All the patients with diabetes medical records in Northwestern Ethiopian specialised hospital. MAIN OUTCOME MEASURES: Exposures were ACEIs plus thiazide diuretics or CCBs collected from March to June 2020. Outcomes were defined as declining in estimated glomerular filtration rate (eGFR) values by ≥30% from the baseline recorded from 2015 to 2019. Descriptive and analytical statistics were illustrated to compare the study groups. Kaplan-Meier with log- rank test was used to plot the survival analyses curve. Potential factors substantially associated to renal events were examined using cox proportional hazards model. RESULT: About 20% of patients developed renal events and significant numbers were from hydrochlorothiazide (HCT) users. The mean eGFR levels were significantly higher in patients on CCBs users over the follow-up years compared with HCT-based users. The CCBs users had an 18.8 mL/min/1.73 m(2) higher in eGFR levels at the end of the follow-up period than HCT users (p<0.001). HCT users had shorter survival probability overtime to develop the outcomes compared with CCBs users (p=0.003). The CCBs-based regimen prevented risks of declining in renal function by 56.4% than HCT (p=0.001). Hazards of declining in eGFR levels were 93% higher for the patients with initial systolic blood pressure (SBP) levels were more than 150 mm Hg (p=0.006). CONCLUSION: Compared with HCT, patients on CCBs had significantly prevented risks of renal events. However, both groups appeared with the same cardiovascular events. HCT-based regimen and higher initial SBP levels were significantly associated with eGFR reductions.