24 March 2018
Int J Med Sci 2014; 11(9):897-904. doi:10.7150/ijms.9026
Comparison of the Antialbuminuric Effects of Benidipine and Hydrochlorothiazide in Renin-Angiotensin System (RAS) Inhibitor-Treated Hypertensive Patients with Albuminuria: the COSMO-CKD (
|Age (years)||59.5 ± 11.5||58.4 ± 12.1||0.380**|
|BMI (kg/m2)||26.07 ± 5.44||25.83 ± 4.48||0.654**|
|Systolic BP (mmHg)||144.4 ± 12.5||143.7 ± 12.5||0.641**|
|Diastolic BP (mmHg)||83.6 ± 8.9||84.5 ±9.0||0.332**|
|Pulse rate (bpm)||75.8 ± 10.8||76.5 ± 10.7||0.513**|
|Serum total cholesterol (mg/dl)||200.4 ± 35.3||200.8 ± 36.9||0.919**|
|Serum LDL cholesterol (mg/dl)||117.8 ± 35.4||114.7 ± 32.2||0.403**|
|Serum HDL cholesterol (mg/dl)||56.8 ± 15.9||55.3 ± 15.1||0.371**|
|Serum triglycerides (mg/dl)||182.4 ± 143.4||193.1 ± 145.0||0.493**|
|Blood sugar (mg/dl)||141.5 ± 53.0||140.5 ± 54.5||0.864**|
|Hemoglobin A1c (%)||6.37 ± 1.16||6.22 ± 1.12||0.226**|
|AST (IU/l)||25.7 ± 14.1||24.8 ± 10.9||0.510**|
|ALT (IU/l)||25.4 ± 17.5||25.5 ± 21.2||0.962**|
|γ-GTP (IU/l)||39.7 ± 33.7||47.8 ± 52.3||0.088**|
|Serum sodium (mEq/l)||140.5 ± 2.7||140.2 ± 2.5||0.286**|
|Serum potassium (mEq/l)||4.36 ± 0.40||4.36 ± 0.48||1.000**|
ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BMI, body mass index; BP, blood pressure; γ-GTP, gamma-glutamyl transpeptidase; HDL, high density lipoprotein; LDL, low density lipoprotein.
* Fisher's exact test, ** t-test.
Changes in the urinary albumin/creatinine ratio (UACR). a) The decrease in UACR was greater in the hydrochlorothiazide group than in the benidipine group, as indicated by the endpoint/baseline ratio of the UACR for each drug. Data (black and white circles) are given as the mean ± the standard deviation (SD). LOCF, last observation carried forward. * The endpoint/baseline ratio of the UACR for each drug is given as the mean (95% confidence interval). b) The endpoint/baseline data are given as the ratio of the benidipine arm/hydrochlorothiazide arm (mean and 95% confidence interval). The non-inferiority of benidipine was not demonstrated.(Click on the image to enlarge.)
Serum creatinine levels were similar at baseline (0.961 (0.919, 1.005) mg/dl, benidipine; 0.967 (0.922, 1.014) mg/dl, hydrochlorothiazide) and at the LOCF (1.039 (0.986, 1.096) mg/dl, benidipine; 1.054 (0.998, 1.114) mg/dl, hydrochlorothiazide). However, serum creatinine levels were slightly and similarly increased by both treatments (Figure 3a). By contrast, eGFR values were also similar at baseline (57.91 (55.31, 60.64) ml/min/1.73m2, benidipine; 57.01 (54.05, 54.05) ml/min/1.73m2, hydrochlorothiazide) and at the LOCF (52.81 (49.94, 55.84) ml/min/1.73m2, benidipine; 51.55 (43.36, 54.95) ml/min/1.73m2, hydrochlorothiazide) (Figure 3b), but the eGFR values were slightly and similarly decreased.
Table 2 shows that the distribution of CKD stages, as assessed by the eGFR, was largely comparable between baseline and the LOCF for both drug groups. CKD staging was also similar between the two groups at each time point. However, a marked increase (from 1.2 (0.1, 4.2)% at baseline to 10.1 (6.0, 15.7)% at the LOCF) was observed in the number of stage 4 patients after hydrochlorothiazide treatment. At the same time point, the number of stage 4 patients in the benidipine group increased from 1.2 (0.1, 4.2)% at the baseline to 5.3 (2.4, 9.8)% at the LOCF.
CKD stages due to the eGFR at baseline and at the LOCF.
|N||%||95% CI||n||%||95% CI|
|Stage 1||9||5.3||2.4, 9.8||16||9.5||5.5, 15.0||0.150|
|Stage 2||78||45.6||38.0, 53.4||61||36.3||29.0, 44.1||0.098|
|Stage 3||82||48.0||40.3, 55.7||89||53.0||45.1, 60.7||0.386|
|Stage 4||2||1.2||0.1, 4.2||2||1.2||0.1, 4.2||1.000|
|Stage 5||0||0.0||0.0, 2.1||0||0.0||0.0, 2.2||-|
|Stage 1||7||4.1||1.7, 8.3||12||7.1||3.7, 12.1||0.246|
|Stage 2||66||38.6||31.3, 46.3||50||29.8||23.0, 37.3||0.109|
|Stage 3||88||51.5||43.7, 59.2||88||52.4||44.5, 60.1||0.914|
|Stage 4||9||5.3||2.4, 9.8||17||10.1||6.0, 15.7||0.105|
|Stage 5||1||0.6||0.0, 3.2||1||0.6||0.0, 3.3||1.000|
CI, confidence interval; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; LOCF, last observation carried forward.
* Fisher's exact test.
BUN values were similar between the two drugs at baseline (17.57 (16.85, 18.32) mg/dl, benidipine; 17.28 (16.49, 18.11) mg/dl, hydrochlorothiazide) and at the LOCF (18.14 (17.31, 19.01) mg/dl, benidipine; 18.84 (17.84, 19.89) mg/dl, hydrochlorothiazide). However, although BUN levels did not appreciably change over the course of the study in the benidipine group (endpoint/baseline ratio, 1.02 (0.98, 1.07)), they were slightly albeit significantly increased in the hydrochlorothiazide group (1.09 (1.05, 1.13)). Hence, the non-inferiority of benidipine was demonstrated in terms of BUN content (benidipine arm/hydrochlorothiazide arm, 0.98 (0.89, 1.00)).
Urinary L-FABP values were also comparable between the two drug groups at baseline (15.20 (12.92, 17.88) μg/g, benidipine; 13.94 (11.70, 16.60) μg/g, hydrochlorothiazide) and at the LOCF (18.67 (15.47, 22.53) μg/g, benidipine; 13.44 (11.22, 16.11) μg/g, hydrochlorothiazide). L-FABP levels showed a slight but significant increase in the benidipine group (endpoint/baseline ration, 1.27 (1.10, 1.46)), but not in the hydrochlorothiazide group (endpoint/baseline ratio, 0.98 (0.84, 1.13)). The non-inferiority of benidipine was not suggested (benidipine arm/hydrochlorothiazide arm, 1.30 (1.06, 1.59)).
Systolic and diastolic BP readings showed similar baseline values between the two drug groups. The systolic BP was 144.4 (142.5, 146.2) mmHg for benidipine and 143.7 (141.9, 145.6) mmHg for hydrochlorothiazide, and the diastolic BP was 83.6 (82.2, 84.9) mmHg for benidipine and 84.5 (83.1, 85.9) mmHg for hydrochlorothiazide, respectively. Systolic and diastolic BP both decreased with drug treatment, and their decrements were similar between the two groups (Figure 4).
Changes in serum creatinine (a) and estimated glomerular filtration rate (eGFR) (b). Data (black and white circles) are given as the mean ± the standard deviation (SD). LOCF, last observation carried forward. * The endpoint/baseline ratios for benidipine and hydrochlorothiazide are each given as the mean (95% confidence interval).(Click on the image to enlarge.)
Changes in systolic and diastolic blood pressure (BP). Data are given as the mean ± the standard deviation (SD). LOCF, last observation carried forward. * Changes in the BP from the baseline to the endpoint are shown as the mean (95% confidence interval).(Click on the image to enlarge.)
Adverse events occurred in 65 of 176 patients (36.9%) in the benidipine group and 74 of 170 patients (43.5%) in the hydrochlorothiazide group. Severe adverse events included one case of vitreous hemorrhage with aggravation of diabetic retinopathy and one case of cerebral bleeding in the benidipine group, and one case each of arteriosclerotic obliteration, gangrene of right third toe, and cerebral infarction with death in the hydrochlorothiazide group. There were no patients in whom renal events occurred, serious or otherwise.
The present study failed to demonstrate the non-inferiority of the antialbuminuric effect of benidipine versus hydrochlorothiazide in RAS inhibitor-treated hypertensive patients with macroalbuminuria. The effect of benidipine appeared to be rather inferior to that of hydrochlorothiazide in terms of UACR (Figure 2b), even though the previous studies report that benidipine decreases urinary albumin/protein more efficaciously in patients with a wide range of CKD stages than other CCBs, such as amlodipine [9-11]. Therefore, although we did not directly compare antialbuminuric actions between benidipine and amlodipine, the current investigation together with the previous data [9-11] suggest that the potency of benidipine to decrease urinary albumin might be intermediate between the less effective CCBs and the more effective thiazide diuretics.
Benidipine and hydrochlorothiazide decreased the eGFR to a similar extent in the present COSMO-CKD trial, although its actions of both drugs on the kidney were fairly weak. On the other hand, amlodipine had a slightly but significantly lower propensity than hydrochlorothiazide to decrease the eGFR in the GUARD study . These results indirectly suggest that amlodipine, but not benidipine, exclusively dilates the afferent artery via L-type calcium channel blockade to increase glomerular pressure, as shown previously . Hence the blockade of T- and N-type calcium channels by benidipine, aside from its L-type calcium channel-blocking effects, may dilate both afferent and efferent arteries, leading to decreasing glomerular pressure, which might protect kidney. However, weaker antialbuminuric effect of benidipine than hydrochlorothiazide suggest that benidipine is less beneficial on the kidney, although both drugs did similarly reduce office systolic and diastolic BP.
Thus, thiazide diuretics may have a potent effect to decrease urinary albumin. Recently, the combination of losartan and hydrochlorothiazide decreased morning BP to a greater extent than high-dose losartan. The combination was also associated with a larger decrease in the UACR . Furthermore, the effects of the thiazide diuretic to ameliorate circadian BP (from a non-dipper pattern to a dipper pattern) and to suppress proteinuria have been demonstrated in RAS inhibitor-treated patients with immunoglobulin A nephropathy . Daytime salt retention is proposed to cancel the normal nighttime reduction in the BP; nighttime high BP accelerates pressure natriuresis to excrete sodium retained during the day. However, diuretics are thought to attenuate daytime sodium retention, resulting in reduced nighttime BP. Nonetheless, daytime and nighttime BP were not examined in the present study. At any rate, thiazide diuretics, which have a different mechanism of action from RAS inhibitors to decrease urinary albumin, may confer greater renoprotective in combination with RAS inhibitors than L-/T-/N-type CCBs such as benidipine, which has a similar renoprotective mechanism (efferent arteriole vasodilation) as RAS inhibitors.
Another recent study  demonstrated the non-inferiority of the antialbuminuric effect of azelnidipine, another so-called “renoprotective” CCB , compared with the thiazide diuretic, trichloromethiazide. Because several different mechanisms have been attributed to the “renoprotective” CCBs (e.g., T-type calcium channel blockade (benidipine), N-type calcium channel blockade (benidipine and cilnidipine), and sympatholytic effects (azelnidipine)), the extent of antialbuminuric action might be different among these agents.
In addition, the subjects of the present study and the above-mentioned study  showed different degrees of albuminuria; ≥ 300 mg/g and 30-600 mg/g, respectively. Recently, Ogawa et al. demonstrated that the antialbuminuric effects of ARB were weakened in patients with ≥1,000 mg/g of UACR . Thus, amelioration of glomerular microcirculation may not effectively decrease urinary albumin in CKD patients with the advanced renal dysfunction. Therefore, the non-inferiority of benidipine versus hydrochlorothiazide might be observed in RAS inhibitor-treated CKD patients with lower UACR values.
Another consideration is that the majority of the patients included in the present study had diabetes (Table 1). Macroalbuminuric patients with diabetes may have advanced diabetic vascular damage, which might also suppress the effectiveness of other “renoprotective” CCB . In addition, there are few reports that compare the antialbuminuric effects between so-called “renoprotective” CCB and thiazide diuretics. Moreover, future investigations are required to examine whether the antiproteinuric effect of benidipine and other “renoprotective” CCBs diuretic is non-inferior compared with thiazides in patients with microalbuminuria.
The present study has several limitations. First, UACR values in spot urine samples can vary with each measurement, even in the same patient with the same drug treatment. In this regard, measurement of urinary albumin excretion in samples collected over a 24-h period or repeated measurements of the first morning void sample may be more accurate than a spot sample. Second, sample size estimation was done in the absence of previous reports comparing the antialbuminuric effects of “renoprotective” CCBs and thiazide diuretics. For this reason, we cannot guarantee that the sample size was sufficient.
In conclusion, the COSMO-CKD trial failed to demonstrate the non-inferiority of the antialbuminuric effect of benidipine relative to hydrochlorothiazide. Several previous studies showed the renoprotective actions of benidipine in CKD patients with various stages of disease, as well as its potentially beneficial actions on glomerular microcirculation. Thus, the renoprotective effect of benidipine might be limited compared with more potent thiazide diuretics, but more pronounced than that of other CCBs. Further studies are required to clarify in the subset of CKD patients in which benidipine most effectively decreases urinary albumin content.
The COSMO-CKD trial was funded by the Kidney Foundation of Japan.
The first author (K.A.) is endowed by Daiichi-Sankyo, Co., Ltd. (Tokyo, Japan). The last author (T.F.) is endowed by Mochida Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Ltd., Kyowa Hakko Kirin Co., Ltd., MSD Co., Ltd., Toray Industries, Inc., and Terumo Cooperation (all in Tokyo, Japan).
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Corresponding author: Katsuyuki Ando, M.D. Department of Nephrology and Endocrinology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan. Telephone: +81-3-5800-9119, Fax: +81-3-5800-9119 E-mail: katsua-tkyac.jp