Introduction: Hypertension has been identified as one of the commonest modifiable determinants for chronic kidney disease progression. A variety of antihypertensive drugs are available and their effect on kidney function has been investigated by a large number of randomized controlled trials. Observational studies, although scarcely been used, outpatient can reflect everyday practice, where drug exposures vary over time, and may provide an alternative for detecting longitudinal changes in kidney function.
Materials and methods: We applied mixed model repeated measures analysis to investigate the effect of antihypertensive drug categories and their combinations on kidney function change over time in a cohort of 779 patients with essential hypertension, using the data from a Greek hypertension outpatient clinic. Antihypertensive drugs were grouped in 5 categories. Their effect was evaluated and their combinations with and without renin-angiotensin-system inhibitors (RASI) to each other. In addition, the combination of RASI with calcium channel blockers (CCBs) was studied.
Results: Diuretics, RASI, CCBs, and beta-blockers had a significant renoprotective and blood pressure lowering effect. Combinations with RASI had a smaller beneficial effect on kidney function compared to CCBs (0.75 mL/min/1.73 m2 per year of drug use versus 0.97 mL/min/1.73 m2). There was no additional effect when combining RASI with CCBs. However, the lowering effect on systolic blood pressure was greater (-0.83 mm Hg per year of drug use, P < .001).
Conclusions: RASI were found to have a smaller, although significant, renoprotective effect. There was no additional effect on kidney function when combining RASI with CCBs.