Should All Hypertensive Dialysis Patients Receive a Blocker of the Renin-Angiotensin System?

Effect of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on cardiovascular outcomes in dialysis patients: a systematic review and meta-analysis

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) and/or angiotensin receptor blockers (ARBs) are recommended by guidelines as first-line antihypertensive therapies in the general population or in patients with earlier stages of kidney disease. However, the cardioprotective benefit of these agents among patients on dialysis remains uncertain.

METHODS

We searched the MEDLINE, PubMed and Cochrane databases from inception through February 2022 to identify randomized controlled trials (RCTs) comparing the efficacy of ACEIs/ARBs relative to placebo or no add-on treatment in patients receiving dialysis. RCTs were eligible if they assessed fatal or non-fatal cardiovascular events as a primary efficacy endpoint.

RESULTS

We identified five RCTs involving 1582 dialysis patients. Compared with placebo or no add-on treatment, the use of ACEIs/ARBs was not associated with a significantly lower risk of cardiovascular events {risk ratio [RR] 0.79 [95% confidence interval (CI) 0.57-1.11]}. Furthermore, there was no benefit in cardiovascular mortality [RR 0.82 (95% CI 0.59-1.14)] and all-cause mortality [RR 0.86 (95% CI 0.64-1.15)]. These results were consistent when the included RCTs were stratified by subgroups, including hypertension, ethnicity, sample size, duration of follow-up and quality.

CONCLUSION

The present meta-analysis showed that among patients on dialysis, the use of ACEIs/ARBs is not associated with a significantly lower risk of cardiovascular events and all-cause mortality as compared with placebo or no add-on treatment.

Effect of amlodipine versus bisoprolol in hypertensive patients on maintenance hemodialysis: A randomized controlled trial

BACKGROUND

Left ventricular hypertrophy and asymmetric dimethylarginine (ADMA) are surrogate markers of cardiovascular disease (CVD) in the dialysis population. This study aimed to evaluate the effect of a calcium channel blocker-based antihypertensive regimen compared to a beta-blocker-based antihypertensive regimen on left ventricular mass index (LVMI) and ADMA levels in hypertensive patients on hemodialysis (HD).

METHODS

This was a parallel-design, open-label, single-center randomized controlled trial on 46 hypertensive patients on maintenance HD, with no history of CVD. Patients were randomly assigned to receive amlodipine 10 mg/d (n = 23) or bisoprolol 10 mg/d (n = 23). Office-based blood pressure (BP) was targeted to ≤ 140/ 90 mm Hg. The outcome was the change in LVMI and ADMA from baseline to 6 months.

RESULTS

Baseline demographic and clinical characteristics did not vary between groups. After 6 months of treatment, amlodipine-based therapy induced a greater reduction in LVMI from baseline than bisoprolol-based treatment (35 ± 34.2 vs 9.8 ± 35.9 gm/m2; P = .017). A similar reduction in the mean BP occurred with treatment in both groups. ADMA concentration decreased significantly from baseline in the amlodipine group (0.75 ± 0.73 to 0.65 ± 0.67 nmol/mL; P = .001), but increased nonsignificantly in the bisoprolol group (0.64 ± 0.61 to 0.78 ± 0.64 nmol/mL; P = .052).

CONCLUSION

This study showed that compared to a bisoprolol-based regimen, an amlodipine-based antihypertensive regimen resulted in a significantly greater reduction in LVMI and ADMA levels from baseline in hypertensive patients on HD despite similar BP reduction in both groups. These findings support the re-evaluation of amlodipine as a potential first-line antihypertensive treatment in patients on HD without previous CVD.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT04085562, registered September 2019.

Comparative Effectiveness of Renin-Angiotensin System Antagonists in Maintenance Dialysis Patients

BACKGROUND/AIMS

Whether angiotensin converting enzyme inhibitors (ACE) and angiotensin receptor blockers (ARB) are differentially associated with reductions in cardiovascular events and mortality in patients receiving maintenance dialysis is uncertain. We compared outcomes between ACE and ARB users among hypertensive, maintenance dialysis patients.

METHODS

National retrospective cohort study of hypertensive, Medicare-Medicaid eligible patients initiating chronic dialysis between 1/1/2000 to 12/31/2005. The exposure of interest was new use of either an ACEI or ARB. Outcomes were all-cause mortality (ACM) and combined cardiovascular hospitalization or death (CV-endpoint). Cox proportion hazards models were used to compare the effect of ACEI vs ARB use on ACM and, separately, CV-endpoint.

RESULTS

ACM models were based on 3,555 ACEI and 1,442 ARB new users, while CV-endpoint models included 3,289 ACEI and 1,346 ARB new users. After statistical adjustments, ACEI users had higher hazard ratios for ACM (AHR = 1.22, 99% CI 1.05-1.42) and CV-endpoint (AHR = 1.12, 99% CI 0.99-1.27).

CONCLUSIONS

Patients initiating maintenance dialysis who received an ACEI faced an increased risk for mortality and a trend towards an increased risk for CV-endpoints when compared to patients who received an ARB. Validation of these results in a rigorous clinical trial is warranted.

Impact of use of angiotensin II receptor blocker on all-cause mortality in hemodialysis patients: prospective cohort study using a propensity-score analysis

BACKGROUND

It is controversial whether treatment with an angiotensin II receptor blocker (ARB) or a calcium channel blocker (CCB) improves prognosis of hemodialysis (HD) patients.

METHODS

This study was designed as a multicenter prospective cohort study. HD patients (n = 1071) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data, kidney transplantation or retraction of consent during the follow-up period (n = 204) were excluded, and 867 patients contributed to analysis of mortality. Propensity score (PS) for use of ARB and that for CCB was calculated using a multiple logistic regression model.

RESULTS

ARB and CCB were prescribed in 45.6 and 54.7 % of patients at enrollment. During the 3-year follow-up period, all-cause mortality and cardiovascular mortality rates were 18.8 and 5.1 %, respectively. Kaplan-Meier curves showed that all-cause and cardiovascular mortality rates were lower in the ARB group than in the non-ARB group, though the mortality rates were similar in the CCB group and non-CCB group. In PS-stratified Cox regression analysis, ARB treatment was associated with 34 and 45 % reduction of all-cause death and cardiovascular death, respectively. In PS matching analysis, ARB treatment was associated with a significant reduction (46 % reduction) in the risk of all-cause death. A significant impact of CCB treatment on all-cause or cardiovascular mortality was not detected in PS analysis.

CONCLUSIONS

The use of an ARB, but not a CCB, is associated with reduced all-cause and cardiovascular mortalities in patients on HD.

Molecular regulation of the renin-angiotensin system in haemodialysis patients

BACKGROUND

Blockade of the renin-angiotensin system (RAS) exerts beneficial effects in patients with mild-to-moderate chronic kidney disease, yet evidence suggesting a similar benefit in haemodialysis (HD) patients is not available. Furthermore, knowledge of the effects of RAS blockade on systemic RAS components in HD patients is limited. Analysis of the quantity and dynamics of all known peripheral constituents of the RAS may yield important pathomechanistic information of a widespread therapeutic measure in HD patients.

METHODS

Fifty-two HD patients from the following groups were analysed cross-sectionally: patients without RAS blockade (n = 16), angiotensin-converting enzyme inhibitor (ACEi) users (n = 8), angiotensin receptor blocker (ARB) users (n = 11), patients on ACEi plus ARB (dual blockade, n = 8) and anephric patients (n = 9). Ten healthy volunteers served as controls. Angiotensin metabolites were quantified by mass spectrometry.

RESULTS

In general, HD patients showed a broad variability of RAS activity. Patients without RAS blockade displayed angiotensin metabolite patterns similar to healthy controls. ACEi therapy increased plasma Ang 1-10 and Ang 1-7 concentrations, whereas ARB treatment increased both Ang 1-8 and Ang 1-5, while suppressing Ang 1-7 to minimal levels. Dual RAS blockade resulted in high levels of Ang 1-10 and suppressed levels of other angiotensins. Anephric patients were completely devoid of detectable levels of circulating angiotensins.

CONCLUSION

In HD patients, the activity status of the systemic RAS is highly distorted with the emergence of crucial angiotensin metabolites upon distinct RAS blockade. The characterization of molecular RAS patterns associated with specific RAS interfering therapies may help to individualize future clinical studies and therapies.

Chronic renal disease progression: treatment strategies and potassium intake

Disordered potassium homeostasis is a common complication of chronic kidney disease and traditional management focuses on restricting potassium intake to avoid hyperkalemia. Permissive potassium intake carries the risk of hyperkalemia and hyperphosphatemia, and possibly may contribute to the development of uremic neuropathy. Excessive potassium restriction and removal by dialysis carries the risk of worsened chronic hypertension, intradialytic hypotension, renal fibrosis and cyst formation, and ventricular arrhythmias. Cohort studies have associated both hypokalemia and hyperkalemia with increased mortality in CKD. A single study of potassium intake in hemodialysis patients found increased intake associated with increased mortality despite adjustment for serum potassium concentration. We recommend avoiding mandatory potassium restriction in early chronic kidney disease. We endorse routine potassium restriction in advanced chronic kidney disease requiring hemodialysis and close monitoring of serum potassium concentration in any patients receiving renin-angiotensin-aldosterone system blockers.

Impact of race on cumulative exposure to antihypertensive medications in dialysis

BACKGROUND

Racial minorities typically have less exposure than non-minorities to antihypertensive medications across an array of cardiovascular conditions in the general population. However, cumulative exposure has not been investigated in dialysis patients.

METHODS

In a longitudinal analysis of 38,381 hypertensive dialysis patients, prescription drug data from Medicaid was linked to Medicare data contained in United States Renal Data System core data, creating a national cohort of dialysis patients dually eligible for Medicare and Medicaid services. The proportion of days covered (PDC) was calculated to determine cumulative exposure to angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), β-blockers, and calcium-channel blockers (CCDs). The factors associated with use of these medications were modeled through weighted linear regression, with derivation of the adjusted odds ratios (AORs) for exposure.

RESULTS

Relative to non-Hispanic Caucasians, African-American, Hispanic, or Other race/ethnicity were significantly associated with less exposure to β-blockers (AOR 0.56-0.69, P < 0.001 in each case) and CCBs (AOR 0.84-0.85, P < 0.001 in each case); African-American race and Hispanic ethnicity had AORs of 0.78 and 0.73 for ACEIs and ARBs, respectively (P < 0.001 in both cases). Collectively, the odds of exposure to each class of medication for minorities was about three-quarters of that for Caucasians.

CONCLUSIONS

Given that dually Medicare-and-Medicaid-eligible dialysis patients have insurance coverage for prescription medications as well as regular contact with health care providers, differences by race in exposure to antihypertensive medications should with time be minimal among patients who are candidates for these drugs. The causes of differences by race in exposure to antihypertensive medications over the course of time should be further examined.