Renal Sodium Handling in Relation to Environmental and Genetic Factors in Untreated Chinese

Comparison of two single-pill dual combination antihypertensive therapies in Chinese patients: a randomized, controlled trial

BACKGROUND

Current hypertension guidelines recommend combination of an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker with a calcium-channel blocker or thiazide diuretic as initial antihypertensive therapy in patients with monotherapy uncontrolled hypertension. However, to what extent these two different combinations are comparable in blood pressure (BP)-lowering efficacy and safety remains under investigation, especially in the Chinese population. We investigated the BP-lowering efficacy and safety of the amlodipine/benazepril and benazepril/hydrochlorothiazide dual therapies in Chinese patients.

METHODS

In a multi-center, randomized, actively controlled, parallel-group trial, we enrolled patients with stage 1 or 2 hypertension from July 2018 to June 2021 in 20 hospitals and community health centers across China. Of the 894 screened patients, 560 eligible patients were randomly assigned to amlodipine/benazepril 5/10 mg (n = 282) or benazepril/hydrochlorothiazide 10/12.5 mg (n = 278), with 213 and 212 patients, respectively, who completed the study and had a valid repeat ambulatory BP recording during follow-up and were included in the efficacy analysis. The primary outcome was the change from baseline to 24 weeks of treatment in 24-h ambulatory systolic BP. Adverse events including symptoms and clinically significant changes in physical examinations and laboratory findings were recorded for safety analysis.

RESULTS

In the efficacy analysis (n = 425), the primary outcome, 24-h ambulatory systolic BP reduction, was - 13.8 ± 1.2 mmHg in the amlodipine/benazepril group and - 12.3 ± 1.2 mmHg in the benazepril/hydrochlorothiazide group, with a between-group difference of - 1.51 (p = 0.36) mmHg. The between-group differences for major secondary outcomes were - 1.47 (p = 0.18) in 24-h diastolic BP, - 2.86 (p = 0.13) and - 2.74 (p = 0.03) in daytime systolic and diastolic BP, and - 0.45 (p = 0.82) and - 0.93 (p = 0.44) in nighttime systolic and diastolic BP. In the safety analysis (n = 560), the incidence rate of dry cough was significantly lower in the amlodipine/benazepril group than in the benazepril/hydrochlorothiazide group (5.3% vs 10.1%, p = 0.04).

CONCLUSIONS

The amlodipine/benazepril and benazepril/hydrochlorothiazide dual therapies were comparable in ambulatory systolic BP lowering. The former combination, compared with the latter, had a greater BP-lowering effect in the daytime and a lower incidence rate of dry cough.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03682692. Registered on 18 September 2018.

Seasonality in nighttime blood pressure and its associations with target organ damage

There is some evidence that nighttime blood pressure varies between seasons. In the present analysis, we investigated the seasonal variation in ambulatory nighttime blood pressure and its associations with target organ damage. In 1054 untreated patients referred for ambulatory blood pressure monitoring, we performed measurements of urinary albumin-to-creatinine ratio (ACR, n = 1044), carotid-femoral pulse wave velocity (cfPWV, n = 1020) and left ventricular mass index (LVMI, n = 622). Patients referred in spring (n = 337, 32.0%), summer (n = 210, 19.9%), autumn (n = 196, 18.6%) and winter (n = 311, 29.5%) had similar 24-h ambulatory systolic/diastolic blood pressure (P ≥ 0.25). However, both before and after adjustment for confounding factors, nighttime systolic/diastolic blood pressure differed significantly between seasons (P < 0.001), being highest in summer and lowest in winter (adjusted mean values 117.0/75.3 mm Hg vs. 111.4/71.1 mm Hg). After adjustment for confounding factors, nighttime systolic/diastolic blood pressure were significantly and positively associated with ACR, cfPWV and LVMI (P < 0.006). In season-specific analyses, statistical significance was reached for all the associations of nighttime blood pressure with target organ damage in summer (P ≤ 0.02), and for some of the associations in spring, autumn and winter. The association between nighttime systolic blood pressure and ACR was significantly stronger in patients examined in summer than those in winter (standardized β, 0.31 vs 0.11 mg/mmol, P for interaction = 0.03). In conclusion, there is indeed seasonality in nighttime blood pressure level, as well as in its association with renal injury in terms of urinary albumin excretion. Our study shows that there is indeed seasonal variability in nighttime blood pressure, highest in summer and lowest in winter, and its association with renal injury in terms of urinary albumin excretion varies between summer and winter as well.

Clinic and ambulatory blood pressure in relation to the interaction between plasma advanced glycation end products and sodium dietary intake and renal handling

Advanced glycation end product (AGE) clearance may cause renal tubular injuries, such as changes in sodium reabsorption. We hypothesize that AGEs interact with sodium metabolism to influence blood pressure (BP). The study participants were outpatients who were suspected of having hypertension but had not been treated with antihypertensive medication. Clinic and ambulatory blood pressures were measured at baseline (n = 989) and during follow-up (median, 4.4 years, n = 293). Plasma AGE concentrations were measured by enzyme-linked immunosorbent assay. Twenty-four-hour urine was collected for measurements of creatinine, sodium and lithium. In a cross-sectional analysis (n = 989), subjects in the top quintile versus quintiles 1-4 of plasma AGE concentration had significantly (P ≤ 0.004) lower fractional excretion of lithium (18.3% vs. 21.6%) and fractional distal reabsorption rate of sodium (95.0% vs. 95.8%) but similar BP (P ≥ 0.25). However, there was an interaction between plasma AGE concentration and urinary sodium excretion in relation to diastolic BP (P ≤ 0.058). Only in participants with low urinary sodium chloride excretion (≤6 grams/day, n = 189), clinic (84.3 vs. 80.2 mmHg), 24-h (83.9 vs. 80.4 mmHg), daytime (87.8 vs. 84.8 mmHg) and nighttime (75.1 vs. 72.1 mmHg) diastolic BP at baseline were higher (P ≤ 0.05) in the top quintile than in quintiles 1-4 of plasma AGE concentration. In the longitudinal study (n = 383), similar trends were observed, with significant (P ≤ 0.05) differences in the increment in daytime diastolic BP (6.8 vs. -1.7 mmHg) and incidence of ambulatory and treated hypertension (hazard ratio 3.73) during follow-up. In conclusion, AGEs were associated with high BP, probably via enhanced proximal sodium handling and on low dietary sodium intake.

Independent relationships between renal mechanisms and systemic flow, but not resistance to flow in primary hypertension in Africa

AIMS

Whether renal mechanisms of hypertension primarily translate into increases in systemic vascular resistance (SVR) in all populations is uncertain. We determined whether renal mechanisms associate with either increases in SVR (and impedance to flow) or systemic flow in a community of African ancestry.

METHOD

In a South African community sampled across the full adult age range (n = 546), we assessed stroke volume (SV), peak aortic flow (Q), SVR, characteristic impedance (Zc) and total arterial compliance (TAC) from velocity and diameter measurements in the outflow tract (echocardiography) and central arterial pressures. Renal changes were determined from creatinine clearance (glomerular filtration rate, GFR) and fractional Na+ excretion (FeNa+) (derived from 24-h urine collections).

RESULTS

Independent of confounders (including MAP and pressures generated by the product of Q and Zc), SV (and hence cardiac output) (P < 0.0001) and Q (P < 0.01), but not SVR, Zc or TAC (P = 0.09-0.20) were independently associated with decreases in both GFR (index of nephron number) and FeNa+. Through an interactive effect (P < 0.0001), the impact of GFR on SV or Q was strongly determined by FeNa+ and vice versa. The relationship between the GFR-FeNa+ interaction and either SV or Q was noted in those above or below 50 years of age, although neither GFR, FeNa+ nor the interaction were independently associated with SVR, Zc or TAC at any age.

CONCLUSION

Across the full adult lifespan, in groups of African ancestry, renal mechanisms of hypertension translate into increases in systemic flow rather than into resistance or impedance to flow.