Time-Varying Proteinuria and Progression of IgA Nephropathy: A Cohort Study.

RATIONALE & OBJECTIVE: Proteinuria is a surrogate end point for predicting long-term kidney outcomes in IgA nephropathy (IgAN) with levels<1g/day identified as a therapeutic target. However, this threshold has not been sufficiently studied. We quantified the associations of progression of IgAN with various levels of proteinuria. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: 1,530 patients with IgAN and at least 12 months of follow-up at Peking University First Hospital. EXPOSURE: Proteinuria levels updated over time (time-varying proteinuria, TVP). OUTCOME: A composite kidney outcome of a 50% reduction in the estimated glomerular filtration rate or end-stage kidney disease. ANALYTICAL APPROACH: Marginal structural models. RESULTS: After a median follow-up period of 43.5 (IQR, 27.2-72.8) months, 254 patients (16.6%) developed the composite kidney outcome. A graded association was observed between TVP and composite kidney outcomes with higher risk among those with proteinuria of≥0.5g/day. Compared with TVP<0.3g/day, the HRs for proteinuria levels of 0.3 to<0.5g/day, 0.5 to<1.0g/day, 1.0 to<2.0g/day, and≥2.0g/day were 2.22 (95% CI, 0.88-5.58), 4.04 (95% CI, 1.93-8.46), 8.46 (95% CI, 3.80-18.83), and 38.00 (95% CI, 17.62-81.95), respectively. The trend was more pronounced in patients with baseline proteinuria of≥1.0g/day, among whom a higher risk was observed with TVP of 0.3 to<0.5g/day compared with TVP<0.3g/day (HR, 3.26 [95% CI, 1.07-9.92], P=0.04). However, in patients with baseline proteinuria levels of<1g/day, the risk of composite kidney outcome only began to increase when TVP was≥1.0g/day (HR, 3.25 [95% CI, 1.06-9.90]). LIMITATIONS: Single-center observational study, selection bias, and unmeasured confounders. CONCLUSIONS: This study showed that patients with IgAN and proteinuria levels of>0.5g/day, have an elevated risk of kidney failure especially among patients with proteinuria levels≥1.0g/day before initiating treatment. These data may serve to inform the selection of proteinuria targets in the treatment of IgAN. PLAIN-LANGUAGE SUMMARY: The presence of proteinuria has often been considered a surrogate end point and a possible therapeutic target in clinical trials in IgA nephropathy (IgAN). Some guidelines recommend a reduction in proteinuria to<1g/day as a treatment goal based on the results of previous longitudinal studies. However, these findings may have been biased because they did not properly adjust for time-dependent confounders. Using marginal structural models to appropriately account for these confounding influences, we observed that patients with IgAN and proteinuria levels≥0.5g/day have an elevated risk of kidney failure, especially among patients who had proteinuria levels of≥1.0g/day before initiating treatment. These data may serve to inform the selection of proteinuria targets in the treatment of IgAN.

MTMR3 risk alleles enhance Toll Like Receptor 9-induced IgA immunity in IgA nephropathy.

Multiple genome-wide association studies (GWASs) have reproducibly identified the MTMR3/HORMAD2/LIF/OSM locus to be associated with IgA nephropathy (IgAN). However, the causal variant(s), implicated gene(s), and altered mechanisms remain poorly understood. Here, we performed fine-mapping analyses based on GWAS datasets encompassing 2762 IgAN cases and 5803 control individuals, and identified rs4823074 as the candidate causal variant that intersects the MTMR3 promoter in B-lymphoblastoid cells. Mendelian randomization studies suggested the risk allele may modulate disease susceptibility by affecting serum IgA levels through increased MTMR3 expression. Consistently, elevated MTMR3 expression in peripheral blood mononuclear cells was observed in patients with IgAN. Further mechanistic studies in vitro demonstrated that MTMR3 increased IgA production dependent upon its phosphatidylinositol 3-phosphate binding domain. Moreover, our study provided the in vivo functional evidence that Mtmr3-/- mice exhibited defective Toll Like Receptor 9-induced IgA production, glomerular IgA deposition, as well as mesangial cell proliferation. RNA-seq and pathway analyses showed that MTMR3 deficiency resulted in an impaired intestinal immune network for IgA production. Thus, our results support the role of MTMR3 in IgAN pathogenesis by enhancing Toll Like Receptor 9-induced IgA immunity.

Discontinuation of Renin-Angiotensin System Inhibitors and Clinical Outcomes in Chronic Kidney Disease: A Systemic Review and Meta-Analysis.

BACKGROUND: Discontinuation of renin-angiotensin system (RAS) inhibitors is common in patients with chronic kidney disease (CKD), and the potential danger has been reported in several studies. However, a comprehensive analysis has not been conducted. OBJECTIVES: This study sought to evaluate the effects of discontinuation of RAS inhibitors in CKD. METHOD: Relevant studies up to November 30, 2022, were identified in the PubMed, Embase, Web of Science, and Cochrane Library databases. Efficacy outcomes included the composite of all-cause mortality, cardiovascular events, and end-stage kidney disease (ESKD). Results were combined using a random-effects or fixed-effects model, and sensitivity analysis used the leave-one-out method. RESULTS: Six observational studies and one randomized clinical trial including 244,979 patients met the inclusion criteria. Pooled data demonstrated that discontinuation of RAS inhibitors was associated with an increased risk of all-cause mortality (HR 1.42, 95% CI 1.23-1.63), cardiovascular event risk (HR 1.25, 95% CI 1.17-1.22), and ESKD (HR 1.23, 95% CI 1.02-1.49). In sensitivity analyses, the risk for ESKD was reduced. Subgroup analysis showed that the risk of mortality was more pronounced in patients with eGFR above 30 mL/min/m2 and in patients with hyperkalemia-related discontinuation. In contrast, patients with eGFR below 30 mL/min/m2 were at great risk of cardiovascular events. CONCLUSIONS: The discontinuation of RAS inhibitors in patients with CKD was associated with a significantly increased risk of all-cause mortality and cardiovascular events. These data suggest that RAS inhibitors should be continued in CKD if the clinical situation allows.

Intensive blood pressure control and the progression of IgA nephropathy: a cohort study using marginal structural models.

BACKGROUND: In chronic kidney disease, current guidelines recommend systolic blood pressure (SBP) below 120 mmHg. However, the renoprotective effect of intensive blood-pressure (BP) lowering on immunoglobulin A nephropathy (IgAN) remains undetermined. We aimed to determine the effect of intensive BP control on the progression of IgAN. METHODS: At Peking University First Hospital, 1530 patients with IgAN were enrolled. An examination of the relationship between baseline and time-updated BP and composite kidney outcomes, defined as development of end-stage kidney disease (ESKD) or a 30% decline in estimated glomerular filtration rate (eGFR), was conducted. Baseline and time-updated BPs were modeled using multivariate causal hazards models and marginal structural models (MSMs). RESULTS: In a median follow-up of 43.5 (interquartile range 27.2, 72.7) months, 367 (24.0%) patients experienced the composite kidney outcomes. No significant associations were found between baseline BP and the composite outcomes. Using MSMs with time-updated SBP for analysis, a U-shaped association was found. In reference to SBP 110-119 mmHg, hazard ratios (95% confidence intervals) for the SBP categories <110, 120-129, 130-139 and ≥140 mmHg were 1.48 (1.02-2.17), 1.13 (0.80-1.60), 2.21 (1.54-3.16) and 2.91 (1.94-4.35), respectively. The trend was more prominent in patients with proteinuria ≥1 g/day and eGFR ≥60 mL/min/1.73 m2. After analyzing time-updated diastolic BP, no similar trend was observed. CONCLUSIONS: In patients with IgAN, intensive BP control during the treatment period may retard the kidney disease progression, but the potential risk of hypotension still needs to be considered.

Corticosteroids in the treatment of IgA nephropathy: lessons from the TESTING trial.

IgA nephropathy (IgAN), the most common form of primary glomerulonephritis, is mainly observed in young adults and children. Clinical and basic studies indicate the role of immunity in IgAN pathogenesis; however, corticosteroid therapy has been controversial in past decades. The TESTING study, initiated in 2012, is an international, multicenter, double-blinded, randomized, placebo-controlled trial that aimed to evaluate oral methylprednisolone's safety and long-term efficacy under conditions of optimized supportive treatment in patients with IgAN whose risk of progression is high. After a decade of effort, the successful completion of the TESTING study showed that a 6- to 9-month course of oral methylprednisolone is an effective regimen to protect kidney function in high-risk patients with IgAN, but also demonstrated safety concerns. Compared with the full-dose regimen, the reduced-dose regimen was reported to be beneficial, with successfully increased safety. Overall, the TESTING trial provided more data regarding the treatment dosage and safety of corticosteroids, a cost-effective therapy, in IgAN, which have important implications for pediatric patients with IgAN. With a deeper understanding of the disease pathogenesis of IgAN, ongoing studies of novel therapeutic regimens would help further optimize the benefit-risk ratio.

Comparison between hydroxychloroquine and systemic corticosteroids in IgA nephropathy: a two-year follow-up study.

BACKGROUND: Hydroxychloroquine (HCQ) is recommended as a treatment for IgA nephropathy (IgAN) to control proteinuria. The long-term effects of HCQ compared to systemic corticosteroid therapy remain unclear. METHODS: We conducted a retrospective case‒control study at Peking University First Hospital. Thirty-nine patients with IgAN who received HCQ for at least 24 months without corticosteroids (CSs) or other immunosuppressive agents were included. Thirty-nine matched patients who received systemic CS therapy were selected using propensity score matching. Clinical data over a 24-month period were compared. RESULTS: In the HCQ group, the level of proteinuria decreased from 1.72 [1.44, 2.35] to 0.97 [0.51, 1.37] g/d (-50.5 [-74.0, -3.4] %, P < 0.001) at 24 months. A significant decline in proteinuria was also found in the CS group, but no significant differences were found between the HCQ group and CS group in the levels of proteinuria (0.97 [0.51, 1.37] vs. 0.53 [0.25, 1.81] g/d, P = 0.707) and change rates (-50.5% [-74.0%, -3.4%] vs. -63.7% [-78.5%, -24.2%], P = 0.385) at 24 months. In addition, the decline rates of eGFR between the HCQ and CS groups were comparable (-7.9% [-16.1%, 5.8%] vs. -6.6% [-14.9%, 5.3%], P = 0.758). More adverse events were observed in the CS group. CONCLUSIONS: Long-term use of HCQ can maintain stable renal function with minimal side effects. In patients who cannot tolerate corticosteroids, HCQ might be an effective and safe supportive therapy for IgAN.

The efficacy and safety of hydroxychloroquine in pregnant patients with IgA nephropathy: A retrospective cohort study.

AIM: Hydroxychloroquine (HCQ) is used to control proteinuria in IgA Nephropathy (IgAN) However, its efficacy and safety in pregnant IgAN patients remains unknown. This study aimed to verify the safety of HCQ in pregnant IgAN patients and compare renal function and pregnancy outcomes with those of patients not treated with HCQ. METHODS: We retrospectively reviewed medical records of all pregnant IgAN patients and singleton gestations at Peking University First Hospital from 2003-2021. Patients who did and did not receive HCQ treatment during pregnancy were compared. RESULTS: We found no significant pre- or post-pregnancy differences in proteinuria or renal function between the two groups. However, the HCQ (+) group had higher proteinuria at the time of kidney biopsy (2.04 [1.26, 2.56] g/d vs. 0.80 [0.44, 1.11] g/d, P < .001); the proteinuria level at HCQ therapy initiation was also higher than that at the beginning of pregnancy (1.87 [1.30, 2.59] g/d vs. 1.08 [0.75, 1.50] g/d, P = .001). Despite no difference in preterm birth, birth weight, preeclampsia or postpartum haemorrhage, the proportion of patients with a previous history of spontaneous abortion was higher in the HCQ (+) group than in the HCQ (-) group (48.0% vs. 20.6%, P = .010). The eGFR (regression coefficient, 0.981; 95%CI 0.964-0.998) was a predictive factor for obstetrical complications. CONCLUSION: HCQ is safe for IgAN treatment during pregnancy with effective reduction of proteinuria. HCQ might also be helpful in patients with a history of spontaneous abortion.

Interaction between GALNT12 and C1GALT1 Associates with Galactose-Deficient IgA1 and IgA Nephropathy.

BACKGROUND: Galactose-deficient IgA1 plays a key role in the pathogenesis of IgA nephropathy, the most common primary GN worldwide. Although serum levels of galactose-deficient IgA1 have a strong genetic component, the genetic link between this molecule and IgA nephropathy has not yet been clearly established. METHODS: To identify novel loci associated with galactose-deficient IgA1, we performed a quantitative genome-wide association study for serum galactose-deficient IgA1 levels, on the basis of two different genome-wide association study panels conducted in 1127 patients with IgA nephropathy. To test genetic associations with susceptibility to IgA nephropathy, we also enrolled 2352 patients with biopsy-diagnosed IgA nephropathy and 2632 healthy controls. Peripheral blood samples from 59 patients and 27 healthy controls were also collected for gene expression analysis. RESULTS: We discovered two loci, in C1GALT1 and GALNT12, that achieved genome-wide significance, explaining about 3.7% and 3.4% of variance in serum galactose-deficient IgA1 levels, respectively. We confirmed the previously reported association of C1GALT1 with serum galactose-deficient IgA1 levels, but with a different lead single-nucleotide polymorphism (rs10238682; ß=0.26, P=1.20×10-9); the locus we identified at GALNT12 (rs7856182; ß=0.73, P=2.38×10-9) was novel. Of more interest, we found that GALNT12 exhibits genetic interactions with C1GALT1 in both galactose-deficient IgA1 levels (P=1.40×10-2) and disease risk (P=6.55×10-3). GALNT12 mRNA expression in patients with IgA nephropathy was significantly lower compared with healthy controls. CONCLUSIONS: Our data identify GALNT12 as a novel gene associated with galactose-deficient IgA1 and suggest novel genetic interactions. These findings support a key role of genetically conferred dysregulation of galactose-deficient IgA1 in the development of IgA nephropathy.

Persistent Hematuria and Kidney Disease Progression in IgA Nephropathy: A Cohort Study.

RATIONALE & OBJECTIVE: Hematuria is the most typical presentation of immunoglobulin A nephropathy (IgAN); however, its role in disease progression is still controversial. This study aimed to evaluate the association of hematuria and progression of IgAN. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: A cohort of 1,333 patients with IgAN treated at a Chinese referral hospital with a median follow-up of 45 months. PREDICTORS: Microhematuria was evaluated in fresh urine using a fully automated urine particle analyzer (automated method) and urine sediment examination by a skilled examiner (manual method). Hematuria was characterized as a time-varying attribute; namely, average hematuria level was calculated for every 6-month period for each patient during follow-up. Remission was defined as average red blood cell count ≤5/high-power field (manual method) or ≤28 red blood cells/µL (automated method) during the first 6 months of follow-up. OUTCOMES: Composite event of 50% decline in estimated glomerular filtration rate or development of kidney failure. ANALYTICAL APPROACH: Multivariable cause-specific hazards models to analyze the relationship between hematuria and the composite kidney disease progression event. RESULTS: Time-varying hematuria during follow-up was an independent risk factor for the composite kidney disease progression event (HR, 1.46; 95% CI, 1.13-1.87; P = 0.003). Hematuria remission during the 6 months after diagnosis was associated with a significantly lower rate of the composite kidney disease progression event (HR, 0.41; 95% CI, 0.28-0.61; P < 0.001). A significant interaction was detected between remission of proteinuria and remission of hematuria during the first 6 months (P < 0.001). The association between remission of hematuria and kidney disease progression was detectable (HR, 0.46; 95% CI, 0.32-0.68) within the subpopulation with persistent proteinuria (protein excretion > 1.0 g/d during the first 6 months), but not among patients whose proteinuria had remitted (HR, 0.64; 95% CI, 0.31-1.29; P = 0.2). The 2 techniques for hematuria evaluation were strongly and significantly linearly correlated (r = 0.948; P < 0.001), and results using these 2 methods were consistent. LIMITATIONS: A single-center retrospective study. Proportional hazards regression incorporating time-varying covariates may create time-varying confounding. The predictive value of reductions in hematuria was not directly evaluated. CONCLUSIONS: Level of hematuria was independently associated with kidney disease progression, whereas hematuria remission was associated with improved kidney outcomes in IgAN among patients with persistent proteinuria. Additionally, to monitor IgAN progression, automated methods to evaluate hematuria hold promise as a replacement for manual evaluation of urinary sediment.

Variation in complement factor H affects complement activation in immunoglobulin A vasculitis with nephritis.

BACKGROUND: Immunoglobulin A (IgA) vasculitis with nephritis (IgAVN) and IgA nephropathy (IgAN) are widely considered as related diseases. Considerable evidences support the notion of involvement of complement activation in both IgAVN and IgAN. Our previous studies identified a genetic variant in complement factor H (CFH), rs6677604, as an IgAN-susceptible variant by genome-wide association study, and further confirmed its linkage to CFHR3-1Δ and proved its influence on complement activation and thereby on IgAN susceptibility. AIM: To explore the role of rs6677604 in complement activation of IgAVN. METHODS: In this study, we enrolled 632 patients with IgAVN, 1178 patients with IgAN and 902 healthy controls. The genotype of rs6677604 was measured by TaqMan allele discrimination assays or was extracted from genome-wide association study data. RESULTS: The frequency of the rs6677604-A allele was significantly higher in IgAVN than in IgAN. However, no significant differences were observed between IgAVN and the controls. Higher complement factor H (FH) levels were observed in IgAVN than IgAN, and positive correlation between circulating FH and C3 levels was present in IgAVN. In both IgAVN and IgAN, rs6677604-A was associated with less intensity of glomerular C3 deposits. In agreement with the higher frequency of rs6677604-A in IgAVN, the glomerular C3 deposits of patients with IgAVN were less intense than those in IgAN. CONCLUSION: Our findings suggest that genetic variation in CFH (rs6677604) is involved in the phenotype of complement activation in both IgAVN and IgAN. Moreover, rs6677604 might contribute to the difference of complement activation intensity between IgAVN and IgAN.

Effect of hydroxychloroquine in patients with IgA nephropathy with insufficient responses to immunosuppressive therapy: a retrospective case-control study.

BACKGROUND: Hydroxychloroquine (HCQ) is a well-known immunomodulator that was recently used in immunoglobulin A (IgA) nephropathy (IgAN) due to its antiproteinuric effects. We investigated the effects of HCQ in patients with IgAN whose proteinuria remained above 1 g/d after conventional immunosuppressive (IS) therapy. METHODS: This study was a retrospective case-control study. Twenty-six patients with IgAN who received HCQ and had insufficient responses to IS therapy (corticosteroid (CS) therapy with/without IS agents) were included. Twenty-six matched historical controls who received conventional IS therapy were selected using propensity score matching. The clinical data from 6 months were compared. RESULTS: Proteinuria at baseline was comparable between the "IS therapy plus HCQ" and "conventional IS therapy" groups (2.35 [interquartile range (IQR), 1.47, 2.98] vs. 2.35 [IQR, 1.54, 2.98] g/d, p = 0.920). A significant reduction in proteinuria was noted in IgAN patients with HCQ treatment (2.35 [IQR, 1.47, 2.98] vs. 1.10 [IQR, 0.85, 1.61] g/d, p = 0.002). The percent reduction in proteinuria at 6 months was similar between the two groups (- 39.81% [- 66.26, - 12.37] vs. -31.99% [- 67.08, - 9.14], p = 0.968). The cumulative frequency of patients with a 50% reduction in proteinuria during the study was also comparable between the two groups (53.8% vs. 57.7%, p = 0.780). No serious adverse events (SAEs) were observed during the study. CONCLUSIONS: Use of HCQ achieved has similar reduction in proteinuria compared to conventional IS therapy in patients with IgAN who had insufficient responses to IS therapy.

Effects of Hydroxychloroquine on Proteinuria in IgA Nephropathy: A Randomized Controlled Trial.

RATIONALE & OBJECTIVE: Despite optimization of renin-angiotensin-aldosterone system (RAAS) inhibition, patients with immunoglobulin A nephropathy (IgAN) and persistent proteinuria remain at risk for kidney failure. We evaluated the efficacy and safety of hydroxychloroquine (HCQ), an immunomodulator, when added to the treatment regimen of patients with IgAN. STUDY DESIGN: Double-blind, randomized, placebo-controlled, phase 2 clinical trial. SETTING & PARTICIPANTS: Participants had IgAN (proteinuria with protein excretion of 0.75-3.5g/d and estimated glomerular filtration rate>30mL/min/1.73m2) and were receiving optimized RAAS inhibitor therapy. INTERVENTIONS: Patients were randomly assigned 1:1 to receive daily oral HCQ or a placebo for 6 months. OUTCOMES: The primary outcome was percentage change in proteinuria between baseline and 6 months. RESULTS: 60 participants (mean estimated glomerular filtration rate, 53.8mL/min/1.73m2; median urine protein excretion, 1.7g/d) were recruited and randomly assigned to receive HCQ (n=30) or placebo (n=30). Percentage change in proteinuria at 6 months was significantly different between the HCQ group and the placebo group (-48.4% [IQR, -64.2%, -30.5%] vs 10.0% [IQR, -38.7%, 30.6%]; P<0.001, respectively). At 6 months, median proteinuria level was significantly lower in the HCQ group than in the placebo group (0.9 [IQR, 0.6, 1.0] g/d vs 1.9 [IQR, 0.9, 2.6] g/d; P=0.002, respectively). No serious adverse events were recorded during the study in either study group. LIMITATIONS: The short treatment period and lack of postwithdrawal observations limit conclusions about long-term renoprotective efficacy and safety. CONCLUSIONS: HCQ in addition to optimized RAAS inhibition significantly reduced proteinuria in patients with IgAN over 6 months without evidence of adverse events. These findings require confirmation in larger treatment trials. FUNDING: This study was supported by grants from a government entity, the Capital of Clinical Characteristics, and the Applied Research Fund. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT02942381.

Delayed diagnosis of acromegaly in a patient with focal segmental Glomerulosclerosis: a rare case report and literature review.

BACKGROUND: Experimental studies have demonstrated that hypersecretion of growth hormone (GH) is associated with development of glomerular sclerosis. However, clinical case of such condition is very rare. Here we presented a case of focal segmental glomerulosclerosis (FSGS) associated with acromegaly. CASE PRESENTATION: A 63-year-old man was diagnosed as nephrotic syndrome with minimal change disease for 2 years. Prednisone 1 mg/kg/day for 9 months led to no response. After admission, the second kidney biopsy indicated FSGS (NOS variant). On admission, his acromegalic features were noticed and he complained with a 20-year history of soft tissue swelling of hands and feet. Serum GH and insulin-like growth factor 1 (IGF-1) concentrations were both elevated significantly. An oral glucose tolerance test showed inadequate suppression of serum GH. The presence of a pituitary macroadenoma with a diameter of 1.4 cm by MRI confirmed the diagnosis of acromegaly. Then, the tumor was subtotally removed by trans-sphenoidal surgery. Partial remission of proteinuria was achieved 3 months after surgery and maintained during follow-up, with gradual reduce of corticosteroid. CONCLUSIONS: This rare case suggested that the hypersecretion of GH may participate, at least in part, in FSGS development and progression. Early diagnosis and treatment of acromegaly is beneficial.

Comparison of the effects of hydroxychloroquine and corticosteroid treatment on proteinuria in IgA nephropathy: a case-control study.

BACKGROUND: Hydroxychloroquine (HCQ), a well-known immunomodulator, has recently been found to be a promising and safe anti-proteinuric agent for treating IgA nephropathy (IgAN). We aimed to compare the efficacy and safety of HCQ and corticosteroid treatment in patients with IgAN. METHODS: This is a case-control study. Ninety-two patients with IgAN who received HCQ in addition to routine renin-angiotensin-aldosterone system inhibitors (RAASi) therapy were included. Ninety-two matched historical controls who received corticosteroids were selected by propensity score matching. The clinical data over 6 months were compared. RESULTS: Baseline proteinuria levels were comparable between the HCQ and corticosteroid groups (1.7 [1.2, 2.3] vs. 1.8 [1.3, 2.5] g/d, p = 0.96). The percentage reduction in proteinuria at 6 months was smaller in the HCQ group than in the corticosteroid group (- 48.5% [- 62.6, - 31.4] vs. -62.9% [- 81.1, - 34.9], p = 0.006). The time averaged proteinuria within the 6 months of observation was comparable for the HCQ and corticosteroid groups (1.1 [0.8, 1.5] vs. 1.1 [0.5, 1.8] g/d, p = 0.48). The cumulative frequency of patients with a 50% reduction in proteinuria during the study was also comparable between the two groups (52.2% vs. 62.0%, p = 0.25). However, six of the 92 (6.5%) patients suffered from severe adverse events (SAEs) in the corticosteroid group, while no SAEs were observed in the HCQ group (6.5% vs. 0%, p = 0.03). CONCLUSIONS: The antiproteinuric effect of HCQ might be slightly inferior to that of corticosteroids over 6 months in patients with IgAN who were deemed to be candidates for HCQ and not corticosteroids treatment. However, HCQ treatment was safer than corticosteroid treatment.

Prevalence and Disease Burden of Chronic Kidney Disease.

Chronic kidney disease (CKD) has been recognized as a leading public health problem worldwide. The global estimated prevalence of CKD is 13.4% (11.7-15.1%), and patients with end-stage kidney disease (ESKD) needing renal replacement therapy is estimated between 4.902 and 7.083 million. Through its effect on cardiovascular risk and ESKD, CKD directly affects the global burden of morbidity and mortality worldwide. The global increase in this disease is mainly driven by the increase in the prevalence of diabetes mellitus, hypertension, obesity, and aging. But in some regions, other causes such as infection, herbal and environmental toxins are still common. The large number of deaths for poor access to renal replacement therapy in developing countries, and also large increase of patients with ESKD in future, will produce substantial financial burden for even the most wealthy countries. Cost-effectiveness of preventive strategies to reduce the disease burden should be evaluated in relation to the local economic development and resource. Strategies reducing the cardiovascular risk in CKD still need further evaluation in large trials especially including patients with advanced kidney disease or end-stage kidney disease.

Circulating complement factor H-related protein 5 levels contribute to development and progression of IgA nephropathy.

IgA nephropathy (IgAN) is a disease associated with activation of the complement system. But the factors influencing complement activation in IgAN are not fully understood. Complement factor H (FH) is an essential negative regulator of complement C3 activation. Complement factor H-related protein (FHR)-5 shares high sequence similarity with factor H. However, unlike factor H, on binding to activated C3 it enables further activation to proceed. Previously, we reported the contribution of rare variants of the CFHR5 gene to IgAN susceptibility. Here we compared circulating levels of FHR-5 in 1126 patients with IgAN and regular follow-up with those of 153 unrelated healthy individuals to explore the relationship of FHR-5 levels with IgAN development and progression. Circulating FHR-5 levels were significantly elevated in patients with IgAN compared to healthy individuals (median 4.55 [interquartile range 3.58 to 5.85] µg/ml vs 3.19 [interquartile range 2.55 to 3.92] µg/ml). Higher circulating FHR-5 levels were associated with a lower estimated glomerular filtration rate, hypertension, and severe Oxford-T and Oxford-C scores. High FHR-5 levels were independently and significantly associated with a risk of developing either a 30% decline in the estimated glomerular filtration rate or end-stage renal disease (hazard ratio, per standard deviation increment of natural square root transformed FHR-5 of 1.226; 95% confidence interval: 1.106-1.359). Thus, the circulating FHR-5 level is an independent risk factor for IgAN progression.

Effects of Hydroxychloroquine on Proteinuria in Immunoglobulin A Nephropathy.

BACKGROUND: Hydroxychloroquine (HCQ) is a well-known immunomodulator that is useful as in the treatment for lupus because of its inhibitory effect on toll-like receptors and cytokines, which are speculated to play a role in the pathogenesis of Immunoglobulin A (IgA) nephropathy (IgAN). However, there was only one study that investigated the effect of HCQ on proteinuria in patients with IgAN. METHODS: Ninety patients with IgAN who received HCQ in addition to optimized dosage of renin-angiotensin-aldosterone system inhibitors (RAASi) were recruited for this study, and 90 matched historical controls who received RAASi alone were selected from our registry by the propensity score matching method. Their clinical data were compared at baseline and during follow-up till the termination of HCQ or addition of immunosuppressive agents. RESULTS: The median baseline proteinuria level of the 90 patients who received HCQ was comparable with the RAASi-alone group (1.5 [1.2, 2.1] vs. 1.5 [1.2, 1.9] g/day, p = 0.74). At 6 months post-study initiation, the median proteinuria level in the HCQ group was lower than that in the RAASi-alone group (0.8 [0.7, 1.2] vs. 1.2 [0.8, 1.8] g/day, p = 0.02). The percentage by which proteinuria was reduced in the HCQ group was significantly higher than that in the RAASi-alone group (-43% [-57, -12] vs. -19% [-46, 17], p = 0.01). No serious adverse effects were documented during treatment with HCQ. CONCLUSION: The addition of HCQ to RAASi resulted in a significant and safe reduction in proteinuria in patients with IgAN.

Uric Acid as a Predictor of Immunoglobulin A Nephropathy Progression: A Cohort Study of 1965 Cases.

BACKGROUND: The role of serum uric acid (SUA) level in the progression of Immunoglobulin A nephropathy (IgAN) remains controversial. METHODS: In a cohort of 1,965 cases with biopsy-proven IgAN, we examined the associations of SUA concentration with the primary outcome of a composite of all-cause mortality or kidney failure (defined as a reduction of estimated glomerular filtration rate [eGFR] by 40% from baseline, requirements for dialysis and transplantation), or the outcome of kidney failure alone, assessed using Cox and logistic regression models, respectively, with adjustment for confounders. RESULTS: At baseline, the mean age was 33.37 ± 11.07 years, eGFR was 101.30 ± 30.49 mL/min/1.73 m2, and mean uric acid level was 5.32 ± 1.76 mg/dL. During a median of 7-year follow-up, 317 cases reached the composite outcome of all-cause mortality (5 deaths) or kidney failure (36 cases of dialysis, 5 cases of renal transplantation, and 271 cases with reduction of eGFR by 40% from baseline). After adjustment for demographic and IgAN specific covariates and treatments, a higher quartile of uric acid was linearly associated with an increased risk of the primary outcome (highest versus lowest quartile, hazard ratio [HR] 2.39; 95% CI 1.52-3.75) and kidney failure (highest versus lowest quartile, HR 2.55; 95% CI 1.62-4.01) in the Cox proportional hazards regression models. In the continuous analysis, a 1 mg/dL greater uric acid level was associated with 16% increased risk of primary outcome (HR 1.16, 95% CI 1.07-1.25) and 17% increased risk of kidney failure (HR 1.17, 95% CI 1.08-1.27), respectively, in the fully adjusted model. The multivariate -logistic regression analyses for the sensitive analyses drew consistent results. In the subgroup analyses, significant interactions were detected that patients with mean arterial pressure (MAP) < 90 mm Hg or mesangial hypercellularity had a higher association of SUA with the incidence of the primary outcome than those with MAP ≥90 mm Hg or those without mesangial hypercellularity respectively. Hyperuricemia was not significantly associated with the risk of developing the primary outcome in elder patients (≥32 years old), patients with eGFR < 90 mL/min or with tubular atrophy/interstitial fibrosis. CONCLUSIONS: SUA level may be positively associated with the progression of IgAN. It was noticeable that the association of hyperuricemia with IgAN progression was less significant in patients with elder age, lower eGFR, or tubular atrophy/interstitial fibrosis, which may be due to some more confounders in association with the IgA progression in these patients. Future prospective studies are warranted to confirm these findings and to investigate the underlying mechanisms.