Immunosuppressive agents for treating IgA nephropathy

Efficacy and safety of tacrolimus-based treatment for non-rapidly progressive IgA nephropathy

In this study, we aimed to evaluate the efficacy and safety of tacrolimus-based treatment for immunoglobulin A nephropathy (IgAN). We retrospectively reviewed 127 adult patients with primary IgAN with 24 h urine total protein quantity (24 h UTP) ≥ 1 g and serum creatinine ≤3 mg/dL. All patients were divided into tacrolimus (TAC) and control (non-TAC) groups according to the treatment strategy. Proteinuria remission, remission rate, and adverse events were compared between the two groups. Among the 127 patients, 61 received TAC-based treatment and 66 received non-TAC treatment. TAC group exhibited a more rapid decline in proteinuria than the non-TAC group at 3, 9, and 12 months (p = 0.049, 0.001, and 0.018, respectively). Remission rates at 1, 3, 6, 9, and 12 months were 41.0, 68.9, 80.3, 90.2, and 88.5%, respectively, in the TAC group. These rates were higher than those in the control group at 3, 9, and 12 months (p = 0.030, 0.008, and 0.026, respectively). Complete remission rates at 1, 3, 6, 9, and 12 months were 6.56, 19.7, 37.7, 54.1, and 62.3%, respectively, in the TAC group. These rates were higher than those in the control group at 9 and 12 months (p = 0.013 and 0.008, respectively). The estimated mean time to complete remission was significantly shorter in the TAC group than in the control group (p = 0.028). TAC did not increase the incidence of adverse events. In conclusion, TAC accelerated proteinuria remission in patients with non-rapidly progressive IgAN with no increased risk of adverse events. Further prospective randomized controlled trials are necessary to validate our findings.

Immunosuppressive agents for treating IgA nephropathy

BACKGROUND

IgA nephropathy is the most common glomerulonephritis world-wide. IgA nephropathy causes end-stage kidney disease (ESKD) in 15% to 20% of affected patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a Cochrane review first published in 2003 and updated in 2015.

OBJECTIVES

To determine the benefits and harms of immunosuppression strategies for the treatment of IgA nephropathy.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 9 September 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgA nephropathy in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risk of bias and extracted data. Estimates of treatment effect were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Risks of bias were assessed using the Cochrane tool. Evidence certainty was evaluated using GRADE methodology.

MAIN RESULTS

Fifty-eight studies involving 3933 randomised participants were included. Six studies involving children were eligible. Disease characteristics (kidney function and level of proteinuria) were heterogeneous across studies. Studies evaluating steroid therapy generally included patients with protein excretion of 1 g/day or more. Risk of bias within the included studies was generally high or unclear for many of the assessed methodological domains. In patients with IgA nephropathy and proteinuria > 1 g/day, steroid therapy given for generally two to four months with a tapering course probably prevents the progression to ESKD compared to placebo or standard care (8 studies; 741 participants: RR 0.39, 95% CI 0.23 to 0.65; moderate certainty evidence). Steroid therapy may induce complete remission (4 studies, 305 participants: RR 1.76, 95% CI 1.03 to 3.01; low certainty evidence), prevent doubling of serum creatinine (SCr) (7 studies, 404 participants: RR 0.43, 95% CI 0.29 to 0.65; low certainty evidence), and may lower urinary protein excretion (10 studies, 705 participants: MD -0.58 g/24 h, 95% CI -0.84 to -0.33;low certainty evidence). Steroid therapy had uncertain effects on glomerular filtration rate (GFR), death, infection and malignancy. The risk of adverse events with steroid therapy was uncertain due to heterogeneity in the type of steroid treatment used and the rarity of events. Cytotoxic agents (azathioprine (AZA) or cyclophosphamide (CPA) alone or with concomitant steroid therapy had uncertain effects on ESKD (7 studies, 463 participants: RR 0.63, 95% CI 0.33 to 1.20; low certainty evidence), complete remission (5 studies; 381 participants: RR 1.47, 95% CI 0.94 to 2.30; very low certainty evidence), GFR (any measure), and protein excretion. Doubling of serum creatinine was not reported. Mycophenolate mofetil (MMF) had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, infection, and malignancy. Death was not reported. Calcineurin inhibitors compared with placebo or standard care had uncertain effects on complete remission, SCr, GFR, protein excretion, infection, and malignancy. ESKD and death were not reported. Mizoribine administered with renin-angiotensin system inhibitor treatment had uncertain effects on progression to ESKD, complete remission, GFR, protein excretion, infection, and malignancy. Death and SCr were not reported. Leflunomide followed by a tapering course with oral prednisone compared to prednisone had uncertain effects on the progression to ESKD, complete remission, doubling of SCr, GFR, protein excretion, and infection. Death and malignancy were not reported. Effects of other immunosuppressive regimens (including steroid plus non-immunosuppressive agents or mTOR inhibitors) were inconclusive primarily due to insufficient data from the individual studies in low or very low certainty evidence. The effects of treatments on death, malignancy, reduction in GFR at least of 25% and adverse events were very uncertain. Subgroup analyses to determine the impact of specific patient characteristics such as ethnicity or disease severity on treatment effectiveness were not possible.

AUTHORS' CONCLUSIONS

In moderate certainty evidence, corticosteroid therapy probably prevents decline in GFR or doubling of SCr in adults and children with IgA nephropathy and proteinuria. Evidence for treatment effects of immunosuppressive agents on death, infection, and malignancy is generally sparse or low-quality. Steroid therapy has uncertain adverse effects due to a paucity of studies. Available studies are few, small, have high risk of bias and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible due to a lack of studies. There is no evidence that other immunosuppressive agents including CPA, AZA, or MMF improve clinical outcomes in IgA nephropathy.

Immunosuppressive agents for treating IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is the most common glomerulonephritis world-wide and a cause of end-stage kidney disease (ESKD) in 15% to 20% of patients within 10 years and in 30% to 40% of patients within 20 years from the onset of disease. This is an update of a review first published in 2003.

OBJECTIVES

To determine the benefits and harms of immunosuppression for the treatment of IgAN.

SEARCH METHODS

For this review update we searched the Specialised Register to 19 February 2015 through contact with the Trials Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of treatment for IgAN in adults and children and that compared immunosuppressive agents with placebo, no treatment, or other immunosuppressive or non-immunosuppressive agents.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study risk of bias and extracted data for population characteristics, interventions and outcomes including mortality, infection, hospitalisation, ESKD requiring renal replacement therapy (dialysis or kidney transplantation), doubling of serum creatinine, remission of proteinuria, and end of treatment urinary protein excretion, serum creatinine, and glomerular filtration rate.Estimates of treatment effect and hazards were summarised using random effects meta-analysis. Treatment effects were expressed as relative risk (RR) and 95% confidence intervals (95% CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included 32 studies comprising 1781 participants. Risk of bias within the included studies was generally high: 22 studies (69%) did not describe the method used to generate the randomisation sequence; 24 (75%) did not describe the methods used to conceal allocation; performance bias was not reported or high in 30 studies (94%); detection bias was unclear in 31 studies (97%); attrition bias was low in 14 studies (44%), unclear in eight (25%) and high in 12 studies (38%); reporting bias was low in 21 studies (67%) and high in 10 studies (31%); and four studies received industry funding or were terminated early (13%).Steroids lowered risks of progression to ESKD (6 studies, 341 participants: RR 0.44, 95% CI 0.25 to 0.80), and doubling of serum creatinine (6 studies, 341 participants: RR 0.45, 95% CI 0.29 to 0.69), lowered urinary protein excretion (6 studies, 263 participants: MD -0.49 g/24 h, 95% CI -0.72 to -0.25); and preserved glomerular filtration rate (4 studies, 138 participants: MD 17.87 mL/min/1.73 m(2), 95% CI 4.93 to 30.82) compared to no treatment or placebo. Combining steroids plus renin-angiotensin-system (RAS) inhibitors lowered the risk of progression to ESKD (2 studies, 160 participants: RR 0.16, 95% CI 0.04 to 0.59) and reduced urinary protein excretion (1 study, 38 participants: MD -0.20 g/24 h, 95% CI -0.26 to -0.14) compared with RAS inhibitors or steroids alone. Cytotoxic agents (azathioprine) plus steroid regimens plus dipyridamole increased remission of proteinuria (1 study, 78 participants: RR 1.24, 95% CI 1.01 to 1.52) compared to steroids alone but had uncertain effects on other outcomes.Mycophenolate mofetil plus RAS inhibitors lowered the risk of progression to ESKD (1 study, 40 participants: RR 0.22, 95% CI 0.05 to 0.90), improved remission of proteinuria (1 study, 40 participants: RR 2.67, 95% CI 1.32 to 5.39) and reduced urinary protein excretion (1 study, 40 participants: MD -1.26 g/24 h, 95% CI -1.46 to -1.06). Effects of other immunosuppressive regimens (including cyclosporin, leflunomide) were inconclusive primarily due to insufficient data from the individual studies. Subgroup analyses to determine the impact of patient characteristics on treatment effectiveness were not possible.

AUTHORS' CONCLUSIONS

The optimal management of IgAN remains uncertain although corticosteroid therapy may lower the risks of kidney disease progression and need for dialysis or transplantation. Evidence for treatment effects of immunosuppressive agents on mortality, infection, and cancer is generally sparse or low-quality and insufficient to guide clinical practice. Available RCTs are few, small, have high risk of bias - particularly selective reporting - and generally do not systematically identify treatment-related harms. Subgroup analyses to identify specific patient characteristics that might predict better response to therapy were not possible. Larger placebo-controlled studies of corticosteroid therapy or mycophenolate mofetil which are sufficiently powered to evaluate patient-relevant end points including adverse events and that examine the optimal duration of treatment are now required in populations with IgAN with a range of kidney function.

Screening with urinary dipsticks for reducing morbidity and mortality

BACKGROUND

Urinary dipsticks are sometimes used for screening asymptomatic people, and for case-finding among inpatients or outpatients who do not have genitourinary symptoms. Abnormalities identified on screening sometimes lead to additional investigations, which may identify serious disease, such as bladder cancer and chronic kidney disease (CKD). Urinary dipstick screening could improve prognoses due to earlier detection, but could also lead to unnecessary and potentially invasive follow-up testing and unnecessary treatment.

OBJECTIVES

We aimed to quantify the benefits and harms of screening with urinary dipsticks in general populations and patients in hospitals.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 8 September 2014 through contact with the Trials Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials and other study types that compared urinary dipstick screening with no dipstick screening were eligible for inclusion. We searched for studies that investigated the use of urinary dipsticks for detecting haemoglobin, protein, albumin, albumin-creatinine ratio, leukocytes, nitrite, or glucose, alone or in any combination, and in any setting. We planned to exclude studies conducted in patients with urinary disorders.

DATA COLLECTION AND ANALYSIS

It was planned that two authors would independently extract data from included studies and assess risk of bias using the Cochrane risk of bias tool. However, no studies met our inclusion criteria.

MAIN RESULTS

Literature searches to 8 September 2014 yielded 4298 records, of which 4249 were excluded following title and abstract assessment. There were 49 records (44 studies) eligible for full text assessment; of these 18 studies were not RCTs and 26 studies compared interventions or controls that were not relevant to this review. Thus, no studies were eligible for inclusion.

AUTHORS' CONCLUSIONS

We found no evidence to assess the benefits and harms of screening with urinary dipsticks, which remain unknown.

Comparison of effective impact among tonsillectomy alone, tonsillectomy combined with oral steroid and with steroid pulse therapy on long-term outcome of immunoglobulin A nephropathy

Background

To clarify the therapeutic impact of tonsillectomy and combined therapies of tonsillectomy plus steroid on the long-term prognosis of immunoglobulin A nephropathy (IgAN).

Methods

A retrospective study was conducted on 208 patients with IgAN between 1986 and 2009. According to the strategies for treatments, patients were divided into four groups: tonsillectomy and steroid pulse (TSP, n = 47), tonsillectomy and oral steroid (TOS, n = 33), tonsillectomy alone (T, n = 56), and N group (no particular therapy, n = 72). Multivariate analysis based on the Cox’s regression model was used to assess the relative risk of reaching the outcome of doubling creatinine based on the influence of baseline prognostic factors.

Results

The mean observation periods were 53.8 months in the TSP group, 122.0 months in the TOS group, 102.9 months in the T group, and 84.6 months in the N group. During an observation period, serum creatinine levels doubled as follows: one in the TSP group (2.1 %), two in the TOS group (6.1 %), five in the T group (8.9 %), histological severity, and 22 in the N group (30.6 %). The Cox’s regression proportional hazard model showed that gender, age, histological activity, dialysis induction risk and therapy were associated with doubling creatinine levels. Hazard ratios (95 % CI) and (P value) in T, TOS, and TSP groups versus N were 0.314 (0.11–0.93, P = 0.037), 0.213 (0.04–1.10, P = 0.065), and 0.032 (0.00–0.28, P = 0.002), respectively.

Conclusion

A combination therapy of tonsillectomy and steroid pulse had the most significant therapeutic impact compared to other therapies.

Corticosteroid therapy in IgA nephropathy

The benefits and risks of steroids for the treatment of IgA nephropathy remain uncertain. We systematically searched MEDLINE, EMBASE, and the Cochrane Library for randomized, controlled trials of corticosteroid therapy for IgA nephropathy published between 1966 and March 2011. We identified nine relevant trials that included 536 patients who had urinary protein excretion >1 g/d and normal renal function. Forty-six (8.6%) of these patients developed a kidney failure event, defined as doubling of the serum creatinine/halving of the GFR or ESRD. Overall, steroid therapy was associated with a lower risk for kidney failure (relative risk, 0.32 [95% confidence interval [CI], 0.15-0.67]; P=0.002) and a reduction in proteinuria (weighted mean difference, -0.46 g/d [95% CI, -0.63 to -0.29 g/d]), with no evidence of heterogeneity in these outcomes. Subgroup analysis suggested that the dose modifies the effect of steroids for renal protection (P for heterogeneity=0.030): Relatively high-dose and short-term therapy (prednisone >30 mg/d or high-dose pulse intravenous methylprednisolone with duration ≤1 year) produced significant renal protection, whereas low-dose, long-term steroid use did not. Steroid therapy was associated with a 55% higher risk for adverse events. The quality of included studies was low, however, limiting the generalizability of the results. In conclusion, steroids appear to provide renal protection in patients with IgA nephropathy but increase the risk for adverse events. Reliably defining the efficacy and safety of steroids in IgA nephropathy requires a high-quality trial with a large sample size.

Cyclosporine A vs. methylprednisolone for Henoch-Schönlein nephritis: a randomized trial

Knowledge about how to treat severe Henoch-Schönlein nephritis (HSN) is scarce. The aim of our study is to compare cyclosporine A (CyA) and methylprednisolone pulses (MP) in the treatment of severe HSN. Out of 24 pediatric HSN patients with nephrotic-range proteinuria or crescentic HSN in kidney biopsy, seven were randomized to receive CyA for 12 months at an initial dose of 5 mg/kg and eight to receive 3 MP pulses of 30 mg/kg followed by prednisone for 4 months. The other nine patients received identical treatment without randomization. Kidney biopsies were performed at inclusion and after 2 years. The primary outcomes were the duration of proteinuria and hematuria, estimated glomerular filtration rate, and renal biopsy histology. All the 11 CyA-treated patients achieved resolution of nephrotic-range proteinuria within 3 months, while the MP-group response was slower, and in 6/13 was not achieved with the initial treatment. Additional immunosuppressive treatment was needed in none of the CyA-treated patients but in six patients treated with MP (difference in proportion 46%, p = 0.008). The 2-year control biopsies were similarly improved in both groups. After mean 6.1 years (2.2-10.4 years), 16 patients (eight CyA, eight MP) had no renal symptoms and six (three CyA, three MP) had persistent nephropathy but normal renal function. One MP-treated patient had reduced renal function and another had developed ESRD and received a renal transplant. CyA gave a 100% resolution of nephrotic-range proteinuria and a 100% renal survival rate without additional therapy after a mean follow-up of 6 years. Treatment of HSN with CyA is efficacious, safe and not inferior to MP.

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.

Antithrombotic drug therapy for IgA nephropathy: a meta analysis of randomized controlled trials

BACKGROUND

Antithrombotic agents, including antiplatelet agents, anticoagulants and thrombolysis agents, have been widely used in the management of immunoglobulin A (IgA) nephropathy in Chinese and Japanese populations. To systematically evaluate the effects of antithrombotic agents for IgA nephropathy.

METHODS

Data sources consisted of MEDLINE, EMBASE, the Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese Science and Technology Periodicals Databases (CNKI) and Japana Centra Revuo Medicina (http://www.jamas.gr.jp) up to April 5, 2011. The quality of the studies was evaluated from the intention to treat analysis and allocation concealment, as well as by the Jadad method. Meta-analyses were performed on the outcomes of proteinuria and renal function.

RESULTS

Six articles met the predetermined inclusion criteria. Antithrombotic agents showed statistically significant effects on proteinuria (p<0.0001) but not on the protection of renal function (p=0.07). The pooled risk ratio for proteinuria was 0.53, [95% confidence intervals (CI): 0.41-0.68; I(2)=0%] and for renal function it was 0.42 (95% CI 0.17-1.06; I(2)=72%). Subgroup analysis showed that dipyridamole was beneficial for proteinuria (p=0.0003) but had no significant effects on protecting renal function. Urokinase had statistically significant effects both on the reduction of proteinuria (p=0.0005) and protecting renal function (p<0.00001) when compared with the control group.

CONCLUSION

Antithrombotic agents had statistically significant effects on the reduction of proteinuria but not on the protection of renal function in patients with IgAN. Urokinase had statistically significant effects both on the reduction of proteinuria and on protecting renal function. Urokinase was shown to be a promising medication and should be investigated further.

Comparative effectiveness of medical interventions in adults versus children

OBJECTIVE

To estimate the comparative effectiveness of medical interventions in adults versus children.

STUDY DESIGN

We identified from the Cochrane Database of Systematic Reviews (Issue 1, 2007) meta-analyses with data on at least 1 adult and 1 pediatric randomized trial with binary primary efficacy outcome. For each meta-analysis, we calculated the summary odds ratio of the adult trials and the pediatric trials, respectively; the relative odds ratio (ROR) of the adult versus pediatric odds ratios per meta-analysis; and the summary ROR across all meta-analyses. ROR <1 means that the experimental intervention is more unfavorable in children than adults.

RESULTS

Across 128 eligible meta-analyses (1051 adult and 343 pediatric trials), the summary ROR did not show a statistically significant difference between adults and children (0.96; 95% confidence intervals, 0.86 to 1.08). However, in all meta-analyses except for 1, the individual ROR's 95% confidence intervals could not exclude a relative difference in efficacy over 20%. In two-thirds, the relative difference in observed point estimates exceeded 50%. Nine statistically significant discrepancies were identified; 4 of them were also clinically important.

CONCLUSIONS

Treatment effects are on average similar in adults and children, but available evidence leaves large uncertainty about their relative efficacy. Clinically important discrepancies may occur.

Meta-analysis of Tripterygium wilfordii Hook F in the immunosuppressive treatment of IgA nephropathy

OBJECTIVE

Numerous Chinese patients with IgA nephropathy (IgAN) have benefited from Tripterygium wilfordii Hook F (TwHF) from two decades ago. However, to date there is no systematic evaluation of this remedy for IgAN.

METHODS

We conducted a meta-analysis of all eligible randomized clinical trials (RCTs) to assess the effect of TwHF on IgAN for the first time. In August 2009 a systematic search was performed among eight electronic databases. Review Manager (RevMan) version 5.0 was used.

RESULTS

(i) Four eligible RCTs with 188 participants were included; (ii) The validities of included RCTs were generally acceptable; (iii) TwHF brought about a favorable increase in complete remission (CR) (RR 1.53, 95%CI 1.09 to 2.16, I(2)=12%) and total remission (TR) (RR 1.27, 95%CI 1.08 to 1.48, I(2)=0%) compared with non-TwHF treatment; and this result was further confirmed by intention-to-treat analysis; (iv) Exploiting subgroup meta-analysis, TwHF led to significantly greater improvements of IgAN with non-nephrotic proteinuria with regard to the increase of CR (RR 1.80, 95%CI 1.21 to 2.68, I(2)=0%) and TR (RR 1.32, 95%CI 1.11 to 1.57, I(2)=0%), and decrease of urinary proteinuria excretion (UPE) (MD -467.41 mg/24h, 95%CI -633.99 to -300.82, I(2)=0%). Meanwhile, the renal function was well preserved (MD -2.66 µmol/L, 95%CI -9.26 to 3.94, I(2)=0%). Conclusion Although the results of this meta-analysis should be interpreted with caution and warrant further investigation, TwHF was certainly a valuable and promising immunosuppressive remedy for IgAN, which was in accordance with the accruing evidence from numerous large clinical and experimental studies.

A scoring system to predict renal outcome in IgA nephropathy: a nationwide 10-year prospective cohort study

Background. Immunoglobulin A nephropathy (IgAN) is the most common form of glomerulonephritis, and a substantial number of patients succumb to end-stage renal disease (ESRD). However, prediction of the renal outcome in individual patients remains difficult. We have already published a scoring system using the data in a prospective cohort of IgAN patients followed up from 1995 to 2002.

Methods. The cohort was further followed up until 2005 in 97 clinical units in Japan. The data from 2283 patients were analysed by Cox regression to determine the predictors of ESRD in IgAN, and their β-coefficients were converted into scores to estimate ESRD risk within 10 years.

Results. During the follow-up (median, 87 months), 252 patients developed ESRD. Male sex, age less than 30 years, family histories of chronic renal failure and chronic glomerulonephritis, hypertension, proteinuria, mild haematuria, hypoalbuminaemia, low glomerular filtration rate and a high histological grade at initial renal biopsy were associated with the risk of ESRD in the multivariable analysis. A scoring system was framed to estimate the 10-year ESRD risk using eight variables significant in both univariable and multivariable models. This prognostic score accurately classified patients by risk: patients with estimates of 0–4.9, 5.0–19.9, 20.0–49.9 and 50.0–100% had an observed incidence of 1.7, 8.3, 36.7 and 85.5%, respectively. The corresponding area under the receiver-operating characteristic curve was 0.942 (95% confidence interval, 0.925–0.958).

Conclusion. This validated scoring system to quantitatively estimate ESRD risk during the 10-year follow-up of IgAN patients will serve as a useful prognostic tool in clinical practice.

A novel simpler histological classification for renal survival in IgA nephropathy: a retrospective study

BACKGROUND

Patients with immunoglobulin A (IgA) nephropathy may progress to end-stage renal disease (ESRD) within 10 to 20 years after renal biopsy. We evaluated factors associated with long-term renal survival by using a novel simplified histological classification.

STUDY DESIGN

Retrospective study.

SETTING & PARTICIPANTS

437 patients (296 men, 141 women) with IgA nephropathy seen at our single center from January 1971 to December 2006. Most patients received treatment with renin-angiotensin system inhibitors.

PREDICTORS

Baseline age, sex, presence of hematuria, presence of hypertension, serum creatinine level, urine protein at baseline, and 2 histological classifications.

OUTCOMES & MEASUREMENTS

Relationship of baseline factors to time to ESRD was evaluated by means of univariate and multivariate analysis with log-rank test and the Cox proportional hazard method.

RESULTS

In a mean follow-up of 107.6 months, 72 ESRD events occurred. The 5-, 10-, 15-, and 20-year renal survival rates after renal biopsy were 94.1%, 82.1%, 73.1%, and 60.3%, respectively. Independent baseline predictors of increased ESRD risk were microhematuria with absence of recurrent macrohematuria (adjusted hazard ratio [HR], 2.18; 95% confidence interval [CI], 1.30 to 3.65; P = 0.003), 1.0 mg/dL (88.4 mumol/L) higher serum creatinine level (HR, 1.50; 95% CI, 1.10 to 2.07; P = 0.013), proteinuria with 1.0 g/dL (10.0 g/L) greater protein (HR, 1.28; 95% CI, 1.07 to 1.52; P = 0.006), and grading of histological lesions. A 1-grade increase according to our 3-grade classification was associated with a nearly 6-fold ESRD risk increase (adjusted HR, 5.95; 95% CI, 3.54 to 10.01; P < 0.0001).

LIMITATIONS

Lack of adjustment for changes in treatment that may have occurred during the study period.

CONCLUSIONS

Renal damage progression in patients with IgA nephropathy was associated with microscopic hematuria at clinical onset, increased serum creatinine level, increased proteinuria, and grading of histological lesions. Our classification system appears simpler than other classifications and is associated with ESRD risk, which could help identify individual high-risk patients and stratify patients enrolled in randomized clinical trials into homogeneous groups.

Meta-analysis of antiplatelet therapy for IgA nephropathy

BACKGROUND

Antiplatelet agents have been widely used in the management of immunoglobulin A (IgA) nephropathy in the Japanese population. To systematically evaluate the effects of antiplatelet agents for IgA nephropathy, we conducted a meta-analysis of the published studies.

METHODS

Data sources consisted of MEDLINE, EMBASE, the Cochrane Library, Ityu-shi (Japanese medical database), and bibliographies from the studies. The quality of the studies was evaluated from the intention to treat analysis and allocation concealment, as well as by the Jadad method. Meta-analyses were performed on the outcomes of proteinuria and renal function.

RESULTS

Seven articles met the predetermined inclusion criteria. The use of antiplatelet agents showed statistically significant effects on proteinuria and renal function. The pooled risk ratio for proteinuria was 0.61 (95% confidence intervals (CI) 0.39-0.94) and for renal function it was 0.74 (95% CI 0.63-0.87).

CONCLUSIONS

Antiplatelet agents resulted in reduced proteinuria and protected renal function in patients with IgA nephropathy. However, studies of high-quality design were rare, and most studies assessed surrogate outcomes. More properly designed studies are needed to reach a definitive assessment of this matter.

Parallel Genotyping of 10,204 Single Nucleotide Polymorphisms to Screen for Susceptible Genes for IgA Nephropathy

Introduction: IgA nephritis (IgAN) is the most common glomerulonephritis worldwide. We aim to genotype SNPs (single nucleotide polymorphisms) genomewide in patients with IgAN to search for genetic clues to its aetiology. Materials and Methods: Genotyping for 10,204 SNPs genomewide was done with the Gene Chip Human Mapping 10K Microarray (Affymetrix). Twenty-eight patients with IgAN and 30 normal subjects were screened and analysed for differences in genotype frequency, allele frequency and heterozygosity reduction. Results: Among the most significantly associated SNPs, 48 SNPs were found mapping directly to the intron of 42 genes that localised in 13 somatic chromosomes and chromosome X. Genotype distribution of these SNPs did not deviate from the Hardy-Weinberg equilibrium in normal subjects. The most significantly associated gene, glial cells missing homolog 1 (GCM, 2 =13.05, P = 0.000) is a transcription factor mapped to 6p12.2. GCM1 reported decreased in placenta of patients with pre-eclampsia. The second gene, Tenascin-R (TNR, 2 = 9.85, P = 0.002) is a glycoprotein and extra-cellular matrix component mapped to 1q25.1. Tenascin-R was associated with motor coordination impairment and enhanced anxiety profile in deficient mice. Interestingly, Triadin (TRDN, 2 = 9.16, P = 0.01) is an integral membrane protein mapped to 6q22.31 within the IgAN1 locus. Triadin was shown to participate in cardiac myocyte arrhythemia. However, there is no published study of these genes in IgAN. Conclusion: Forty-two associated genes (particularly GCM1, TNR and TRDN) are identified as possible susceptibility or marker genes for IgAN. Knowledge of their mesangial expression and binding capacity for IgA-containing complexes may help elucidate the pathogenesis of IgAN. Key words: Glomerulonephritis, IgA nephritis