Albuminuria-reducing effect of angiotensin II receptor blocker plus hydrochlorothiazide combination therapy in renal transplant recipients.

In recent years, the combined use of angiotensin II receptor blockers (ARBs) and low-dose diuretics has become clinically possible. Moreover, the GUARD and J-CORE studies have confirmed that the addition of low-dose diuretics to renin-angiotensin system inhibitors reduces albuminuria. In this study, we investigated the clinical effects of a combination drug containing an ARB and a low-dose diuretic in renal transplant recipients. A total of 13 renal transplant recipients who were receiving the maximum dose of the ARB and presenting with microalbuminuria [urine albumin-creatinine ratio (ACR) of 30-300 mg/g-Cre] were converted to a single pill combination drug containing the same amount of the ARB and 12.5 mg of hydrochlorothiazide (HCTZ) and an intervention study of a crossover trial design was conducted. The clinical parameters were measured at baseline, 3 months after ARB/HCTZ conversion and 3 months after reverting to the ARB and the resulting data were compared. Serum creatinine (S-Cre) and uric acid (UA) levels at 3 months after conversion were significantly higher than those at baseline. The levels of the estimated glomerular filtration rate (eGFR) and ACR at 3 months were significantly lower than those at baseline. S-Cre and UA levels at 3 months after reversion were significantly lower than those at 3 months after conversion. The eGFR and levels of ACR and UA at 3 months after ARB reversion were significantly higher than those at 3 months after conversion. The results of this preliminary study suggest that the combination drug containing an ARB and low-dose diuretic was effective for reducing microalbuminuria in renal transplant recipients. In the future, larger cohort studies are needed to confirm these findings.