Renin-Angiotensin System Blockers and the Risk of COVID-19-Related Mortality in Patients with Kidney Failure

COVID-19 and cardiovascular disease in patients with chronic kidney disease

Millions of people worldwide have chronic kidney disease (CKD). Affected patients are at high risk for cardiovascular (CV) disease for several reasons. Among various comorbidities, CKD is associated with the more severe forms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This is particularly true for patients receiving dialysis or for kidney recipients. From the start of the SARS-CoV-2 pandemic, several CV complications have been observed in affected subjects, spanning acute inflammatory manifestations, CV events, thrombotic episodes and arrythmias. Several pathogenetic mechanisms have been hypothesized, including direct cytopathic viral effects on the myocardium, endothelial damage and hypercoagulability. This spectrum of disease can occur during the acute phase of the infection, but also months after recovery. This review is focussed on the CV complications of coronavirus disease 2019 (COVID-19) with particular interest in their implications for the CKD population.

Renin-Angiotensin Aldosterone System Inhibitors and COVID-19: A Systematic Review and Meta-Analysis Revealing Critical Bias Across a Body of Observational Research

Background

Renin‐angiotensin aldosterone system (RAAS) inhibitor—COVID‐19 studies, observational in design, appear to use biased methods that can distort the interaction between RAAS inhibitor use and COVID‐19 risk. This study assessed the extent of bias in that research and reevaluated RAAS inhibitor—COVID‐19 associations in studies without critical risk of bias.

Methods and Results

Searches were performed in MEDLINE, EMBASE, and CINAHL databases (December 1, 2019 to October 21, 2021) identifying studies that compared the risk of infection and/or severe COVID‐19 outcomes between those using or not using RAAS inhibitors (ie, angiotensin‐converting enzyme inhibitors or angiotensin II type‐I receptor blockers). Weighted hazard ratios (HR) and 95% CIs were extracted and pooled in fixed‐effects meta‐analyses, only from studies without critical risk of bias that assessed severe COVID‐19 outcomes. Of 169 relevant studies, 164 had critical risks of bias and were excluded. Ultimately, only two studies presented data relevant to the meta‐analysis. In 1 351 633 people with uncomplicated hypertension using a RAAS inhibitor, calcium channel blocker, or thiazide diuretic in monotherapy, the risk of hospitalization (angiotensin‐converting enzyme inhibitor: HR, 0.76; 95% CI, 0.66–0.87; P<0.001; angiotensin II type‐I receptor blockers: HR, 0.86; 95% CI, 0.77–0.97; P=0.015) and intubation or death (angiotensin‐converting enzyme inhibitor: HR, 0.64; 95% CI, 0.48–0.85; P=0.002; angiotensin II type‐I receptor blockers: HR, 0.74; 95% CI, 0.58–0.95; P=0.019) with COVID‐19 was lower in those using a RAAS inhibitor. However, these protective effects are probably not clinically relevant.

Conclusions

This study reveals the critical risk of bias that exists across almost an entire body of COVID‐19 research, raising an important question: Were research methods and/or peer‐review processes temporarily weakened during the surge of COVID‐19 research or is this lack of rigor a systemic problem that also exists outside pandemic‐based research?

Registration

URL: www.crd.york.ac.uk/prospero/; Unique identifier: CRD42021237859.

COVID-19 in dialysis: clinical impact, immune response, prevention, and treatment

The COVID-19 pandemic has profound adverse effects on the population on dialysis. Patients requiring dialysis are at an increased risk of SARS-CoV-2 infection and mortality, and many have experienced psychological distress as well as delayed or suboptimal care. COVID-19 survivors have prolonged viral shedding, but generally develop a robust and long-lasting humoral immune response that correlates with initial disease severity. However, protection against reinfection is incomplete. A growing body of evidence reveals delayed and blunted immune responses to SARS-CoV-2 vaccination. Administration of a third dose within 1 to 2 months of prime-boost vaccination significantly increases antibody levels, in particular in patients with poor initial responses. Patients on dialysis have inferior immune responses to adenoviral vector vaccines than to mRNA vaccines. The immunogenicity of the mRNA-1273 vaccine is markedly better than that of the BNT162b2 vaccine, most likely by virtue of its higher mRNA content. Despite suboptimal immune responses in patients on dialysis, preliminary data suggest that vaccination partially protects against infection and severe disease requiring hospitalization. However, progressive waning of immunity and emergence of SARS-CoV-2 variants with a high potential of immune escape call for a booster dose in all patients on dialysis 4 to 6 months after prime-boost vaccination. Patients with persistent poor vaccine responses may be candidates for primary prophylaxis strategies. In the absence of specific data in patients on dialysis, therapeutic strategies in the event of established COVID-19 must be extrapolated from evidence obtained in the population not on dialysis. Neutralizing monoclonal antibodies may be an attractive option after a high-risk exposure or during the early course of infection.

The COVID-19 pandemic: progress in nephrology

Patients with kidney disease are particularly vulnerable to COVID-19. In 2021, key studies demonstrated the safety of renin–angiotensin blockade in patients with kidney failure and COVID-19, and provided new data on the therapeutic potential of soluble angiotensin-converting enzyme, COVID-19 vaccine responses and the long-term effects of COVID-19 on kidney function.

Renin–angiotensin system blockade is not associated with increased risk or severity of COVID-19 among patients with kidney failure3 . A truncated form of human soluble angiotensin-converting enzyme 2 (ACE2) protected kidney organoids from SARS-CoV-2 infection4 ; this protein might be a potential preventive or therapeutic agent for COVID-19. In patients with kidney failure, a third dose of the BNT162b2 COVID-19 vaccine was well tolerated and substantially increased anti-SARS-CoV-2 antibodies8 A proportion of patients (13–35%) experience a decline in estimated glomerular filtration rate in the long term following severe COVID-199 ; thus, COVID-19 should be an indication for kidney disease screening.

Renin-angiotensin system blockers during the COVID-19 pandemic: an update for patients with hypertension and chronic kidney disease

Hypertension and chronic kidney disease (CKD) are among the most common comorbidities associated with coronavirus disease 2019 (COVID-19) severity and mortality risk. Renin–angiotensin system (RAS) blockers are cornerstones in the treatment of both hypertension and proteinuric CKD. In the early months of the COVID-19 pandemic, a hypothesis emerged suggesting that the use of RAS blockers may increase susceptibility for COVID-19 infection and disease severity in these populations. This hypothesis was based on the fact that angiotensin-converting enzyme 2 (ACE2), a counter regulatory component of the RAS, acts as the receptor for severe acute respiratory syndrome coronavirus 2 cell entry. Extrapolations from preliminary animal studies led to speculation that upregulation of ACE2 by RAS blockers may increase the risk of COVID-19-related adverse outcomes. However, these hypotheses were not supported by emerging evidence from observational and randomized clinical trials in humans, suggesting no such association. Herein we describe the physiological role of ACE2 as part of the RAS, discuss its central role in COVID-19 infection and present original and updated evidence from human studies on the association between RAS blockade and COVID-19 infection or related outcomes, with a particular focus on hypertension and CKD.