Non-immunosuppressive treatment for IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common primary glomerular disease, with approximately 20% to 40% of patients progressing to kidney failure within 25 years. Non-immunosuppressive treatment has become a mainstay in the management of IgAN by improving blood pressure (BP) management, decreasing proteinuria, and avoiding the risks of long-term immunosuppressive management. Due to the slowly progressive nature of the disease, clinical trials are often underpowered, and conflicting information about management with non-immunosuppressive treatment is common. This is an update of a Cochrane review, first published in 2011. OBJECTIVES: To assess the benefits and harms of non-immunosuppressive treatment for treating IgAN in adults and children. We aimed to examine all non-immunosuppressive therapies (e.g. anticoagulants, antihypertensives, dietary restriction and supplementation, tonsillectomy, and herbal medicines) in the management of IgAN. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to December 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using random-effects meta-analysis. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: This review includes 80 studies (4856 participants), of which 24 new studies (2018 participants) were included in this review update. The risk of bias within the included studies was mostly high or unclear for many of the assessed methodological domains, with poor reporting of important key clinical trial methods in most studies. Antihypertensive therapies were the most examined non-immunosuppressive therapy (37 studies, 1799 participants). Compared to placebo or no treatment, renin-angiotensin system (RAS) inhibition probably decreases proteinuria (3 studies, 199 participants: MD - 0.71 g/24 h, 95% CI -1.04 to -0.39; moderate certainty evidence) but may result in little or no difference to kidney failure or doubling of serum creatinine (SCr), or complete remission of proteinuria (low certainty evidence). Death, remission of haematuria, relapse of proteinuria or > 50% increase in SCr were not reported. Compared to symptomatic treatment, RAS inhibition (3 studies, 168 participants) probably decreases proteinuria (MD -1.16 g/24 h, 95% CI -1.52 to -0.81) and SCr (MD -9.37 µmol/L, 95% CI -71.95 to -6.80) and probably increases creatinine clearance (2 studies, 127 participants: MD 23.26 mL/min, 95% CI 10.40 to 36.12) (all moderate certainty evidence); however, the risk of kidney failure is uncertain (1 study, 34 participants: RR 0.20, 95% CI 0.01 to 3.88; very low certainty evidence). Death, remission of proteinuria or haematuria, or relapse of proteinuria were not reported. The risk of adverse events may be no different with RAS inhibition compared to either placebo or symptomatic treatment (low certainty evidence). In low certainty evidence, tonsillectomy in people with IgAN in addition to standard care may increase remission of proteinuria compared to standard care alone (2 studies, 143 participants: RR 1.90, 95% CI 1.45 to 2.47) and remission of microscopic haematuria (2 studies, 143 participants: RR 1.93, 95% CI 1.47 to 2.53) and may decrease relapse of proteinuria (1 study, 73 participants: RR 0.70, 95% CI 0.57 to 0.85) and relapse of haematuria (1 study, 72 participants: RR 0.70, 95% CI 0.51 to 0.98). Death, kidney failure and a > 50% increase in SCr were not reported. These trials have only been conducted in Japanese people with IgAN, and the findings' generalisability is unclear. Anticoagulant therapy, fish oil, and traditional Chinese medicines exhibited small benefits to kidney function in patients with IgAN when compared to placebo or no treatment. However, compared to standard care, the kidney function benefits are no longer evident. Antimalarial therapy compared to placebo in one study reported an increase in a > 50% reduction of proteinuria (53 participants: RR 3.13 g/24 h, 95% CI 1.17 to 8.36; low certainty evidence). Although, there was uncertainty regarding adverse events from this study due to very few events. AUTHORS' CONCLUSIONS: Available RCTs focused on a diverse range of interventions. They were few, small, and of insufficient duration to determine potential long-term benefits on important kidney and cardiovascular outcomes and harms of treatment. Antihypertensive agents appear to be the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The benefits of RAS inhibition appear to outweigh the harms in patients with IgAN. The certainty of the evidence of RCTs demonstrating a benefit of tonsillectomy to patients with Japanese patients with IgAN was low. In addition, these findings are inconsistent across observational studies in people with IgAN of other ethnicities; hence, tonsillectomy is not widely recommended, given the potential harm of therapy. The RCT evidence is insufficiently robust to demonstrate efficacy for the other non-immunosuppressive treatments evaluated here.

A systematic review and meta-analysis of mortality and kidney function in uranium-exposed individuals.

BACKGROUND: Humans are exposed to uranium (U) in a variety of applications. Both animal and observational human studies support an associated U nephrotoxicity. Few statistical syntheses of the human data have been performed and these analyses are limited in the types of exposures considered. OBJECTIVES: This study aims to evaluate the state of current evidence and to expand on existing meta-analyses by systematically evaluating kidney-associated causes of mortality in multiple U-exposed populations. This study also aims to evaluate the effect of U exposure on kidney function and biomarkers of kidney injury. METHODS: The published and grey literature were systematically reviewed for studies that reported Standardized Mortality Ratios (SMR) for kidney cancer, chronic nephritis/nephrosis, all-cause mortality, diabetes, all circulatory/heart disease, and/or ischemic heart disease in U-exposed humans. Studies that reported kidney biomarker measures for U-exposed versus control subjects were identified separately. RESULTS: 36 studies were included. The studies were parsed into subgroups based on setting of exposure. Analysis of kidney cancer and chronic nephritis/nephrosis mortality demonstrated an SMR of 0.93 (95CI: 0.82-1.05) and 0.82 (95CI: 0.70-0.96), respectively. The other clinical outcomes evaluated also demonstrated mortality deficits in exposed relative to unexposed individuals. Subgroup analyses demonstrated similar mortality deficits. Conversely, biomarker analyses suggested better kidney function in the controls, but none of these differences reached significance. DISCUSSION: Given that most of the included mortality studies were conducted in occupational populations, the mortality deficits observed in our analyses were likely due to the healthy-worker effect. Additionally, our analyses of kidney biomarkers were severely limited by low precision due to a low number of available studies and small study-size. Future work needs to evaluate the progression of chronic and to end-stage kidney disease in community-based populations to better assess the full impact of prolonged chronic U exposure on kidney outcomes.

Non-immunosuppressive treatment for IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common primary glomerular disease with approximately 30% to 40% of patients progressing to end-stage kidney disease (ESKD) within 20 years. The most common regimens include immunosuppressive agents, however the risks of long-term treatment often outweigh the potential benefits. Non-immunosuppressive options, including fish oils, anticoagulants, antihypertensive agents and tonsillectomy have also been examined but not reviewed systematically. OBJECTIVES: To assess the benefits and harms of non-immunosuppressive treatments for treating IgAN in adults and children. SEARCH STRATEGY: In July 2010 we searched the Cochrane Renal Group's specialised register, CENTRAL (in The Cochrane Library), MEDLINE (from 1966) and EMBASE (from 1980). We also searched reference lists of included studies, review articles and contacted local and international experts. SELECTION CRITERIA: Randomised controlled trials (RCTs) of non-immunosuppressive agents in adults and children with biopsy-proven IgAN were included. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed search results, extracted data and assessed study quality. Results were expressed as mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI) using a random-effects model. MAIN RESULTS: We included 56 studies (2838 participants). Antihypertensive agents were the most beneficial non-immunosuppressive intervention for IgAN. The antihypertensives examined were predominantly angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARB) or combinations of both, versus other antihypertensives and other agents. The benefits of antihypertensive agents, particularly inhibitors of the renin angiotensin system, appear to potentially outweigh the harms in patients with IgAN. The benefits are largely manifest as a reduction in proteinuria, a surrogate outcome. There is no evidence that treatment with any of the antihypertensive agents evaluated affect major renal and/or cardiovascular endpoints or long-term mortality risk beyond the benefit that arises from controlling hypertension in patients with IgAN. The RCT evidence is insufficiently robust to demonstrate efficacy for any of the other non-immunosuppressive therapies evaluated here. AUTHORS' CONCLUSIONS: IgAN remains a disease in search of adequately powered RCTs to reliably inform clinical practice. More and better evidence is needed to understand the magnitude of benefit and the possible risks of anti-hypertensive or more specifically of ACEi/ARB therapy alone or in combination and which specific types of patients with the IgAN might have the greatest potential for benefit. For other non-immunosuppressive therapies, where neither benefit nor significant harm has yet to be demonstrated, there remains some justification for further exploration of the potential benefits.