Heterogeneity of prognosis in adult IgA nephropathy, especially with mild proteinuria or mild histological features

The Effect of Hydroxychloroquine on Residual Proteinuria in Patients With Immunoglobulin A Nephropathy: A Retrospective Study Based on Propensity Score Matching

Background

There is insufficient evidence to support the use of hydroxychloroquine (HCQ) in Immunoglobulin A nephropathy (IgAN) patients with high residual proteinuria in spite of 6-month supportive treatment combined with corticosteroids (P) and/or immunosuppressives (IM). This study aims to explore the effect of HCQ on residual proteinuria in IgAN.

Materials and Methods

This is a retrospective study. IgAN patients who had residual proteinuria ≥0.3 g/24 h after 6-month treatment by renin-angiotensin system inhibitors (RASI) + P ± IM were included. Groups were divided based on the different regimens and then matched by the propensity score matching method. The primary outcome was defined as the cumulative frequency of residual proteinuria reduction ≥30%.

Results

RASI (n = 183), HCQ + RASI (n = 59), RASI + P ± IM (n = 145), and HCQ + RASI + P ± IM (n = 38) groups were included. HCQ + RASI group had a higher level of residual proteinuria and a worse renal function than those in the RASI group. The renal function was worse in the HCQ + RASI + P ± IM group than that in the control group, but residual proteinuria levels were similar. After matching, there were 40 patients in the first two groups and 29 patients in the latter two groups, respectively. The cumulative frequency of residual proteinuria reduction ≥30% in HCQ + RASI + P ± IM group was higher than that in control group (86.2% vs. 62.1%, χ2 = 6.397, p = 0.011). HCQ combination treatment was one of independent factors.

Conclusion

The addition of HCQ treatment can effectively reduce the residual proteinuria in IgAN patients previously treated with supportive treatment combined with P and IM treatment and the cumulative frequency of effective reduction of residual proteinuria can reach 86.2%.

The precise long-term outcomes of adult IgA nephropathy by mail questionnaires: Better renal survival compared to earlier cohort studies

The estimated 20-year renal survival rate of immunoglobulin A (IgA) nephropathy is approx. 60%, but it is difficult to determine the 'big picture' for IgA nephropathy because a biopsy is essential for its diagnosis. Here we attempted to determine the longer and more precise renal prognosis of IgA nephropathy. We examined 310 patients with primary IgA nephropathy. Using the patients' clinical records and histological reports from our hospital and other clinics, we surveyed their renal prognoses and treatments within 1 year post-biopsy, and we sent questionnaires to the patients who had stopped visiting any hospital. We set renal death as the primary endpoint and analyzed factors related to renal death. The total patient cohort was 267: 159 males, 108 females; average age at biopsy, 37.7 years; average estimated glomerular filtration rate (eGFR), 69.7 mL/min/1.73m2; urinary protein, 1.3 g/day. The mean follow-up duration was prolonged to 13.8±8.9 years (vs. 9.2±8.5 years using only medical records). The 10- and 20-year follow-up rates were 61.7% and 27.3%. The 10-, 20-year renal survival rates were 83.6% and 72.5%. Lower eGFR, hypertension, and smoking were revealed as factors independently related to renal death. To study survival of relatively benign diseases such as IgA nephropathy, longer survival rate was affected by many censoring cases. The results regarding the long-term renal prognoses of IgA nephropathy patients (including those with a mild phenotype) obtained by our analysis of a questionnaire sent to the patients provided more precise and longer-term prognoses compared to earlier studies.

A Systematic Review on Materno-Foetal Outcomes in Pregnant Women with IgA Nephropathy: A Case of "Late-Maternal" Preeclampsia?

Background: IgA nephropathy is the most common primary glomerulonephritis in pregnancy and shares with other immunologic diseases and kidney diseases a relationship with adverse maternal outcomes, whose entity and pattern is only partially quantified. Recent studies provide new information and a systematic review regarded progression of kidney disease. The discussion of the outcomes with respect to low-risk pregnancies may help to perfect the estimation of the risks, and to identify specific research needs. Methods: A search strategy was built on Medline, EMBASE and the Cochrane review for the period January 2000–April 2017, aimed at retrieving both case series (defined as with at least 6 pregnancies in women with IgA nephropathy) and case reports, to look into rare occurrences. All papers, with or without control groups, were selected if they reported on at least one pregnancy outcome, or on long-term kidney function. Search strategy, paper selection and data extraction were done in duplicate (PROSPERO N 42016042623). Meta-analysis of case series was performed with Metanalyst Beta 3.13. Case reports were analysed narratively. Results: The search retrieved 556 papers, of which 27 were included (13 series and 14 case-reports). The case series report on 581 women with 729 pregnancies. The analysis was performed in comparison to the available control groups: 562 non-pregnant controls were available for the analysis of progression of kidney disease. As for pregnancy related outcomes (preeclampsia (PE), pregnancy induced hypertension (PIH), preterm birth, small babies), we meta-analyzed the data with respect to the only series of low-risk pregnancies (1418 pregnancies). When compared with women who never got pregnant after diagnosis of IgA nephropathy, in the present meta-analysis pregnancy in women with IgA nephropathy was not associated with a higher risk of progression of kidney disease, possibly due to the overall preserved kidney function at baseline: end-stage kidney disease (OR 0.68; CI 0.28–1.65). Conversely, the incidence of adverse pregnancy-related outcomes was increased compared to low-risk controls: PE and PIH were more than ten-fold increased (OR 11.80; CI 7.53–18.48 and OR 10.39; CI 5.45–19.80), while the increase in risk of preterm birth and “low birth weight babies” was less marked (OR 3.37; CI 1.91–5.95 and OR 2.36; CI 1.52–3.66), a discrepancy suggesting the occurrence of “late” or “maternal” PE, that may affect less severely foetal growth or shorten gestation. In conclusion, in the present meta-analysis IgA nephropathy was not associated with an increased progression of kidney disease. The more than ten-fold increased risk of PIH and PE, in combination with a doubled risk of small babies, suggests the occurrence of “late” or “maternal” PE, usually less affecting early foetal growth. This finding may be of help in defining control policies, while further research is needed to guide clinical management.

Tacrolimus decreases proteinuria in patients with refractory IgA nephropathy

In clinical practice, some IgA nephropathy (IgAN) patients show resistance to or are unable to achieve complete remission using steroids and/or immunosuppressants. The current study aimed to assess the efficacy and safety of tacrolimus in the treatment of cases of refractory IgAN.In this retrospective observational study, 34 primary IgAN patients with refractory proteinuria received tacrolimus for at least 12 months. Complete remission, partial remission, and other clinical data were measured at 1, 3, 6, and 12 months after the initiation of treatment.After 12 months, complete remission was achieved in 20 (58.8%) patients and partial remission in 5 (14.7%) patients, yielding a total response rate of 73.5%. The mean time for response to tacrolimus for those who achieved complete remission and partial remission was 7.0 ± 4.7 weeks. Serum creatinine (Scr), uric acid, estimated glomerular filtration rate, alanine aminotransferase, aspartate transaminase, white blood cell count, blood pressure, blood glucose, total cholesterol, and total triglyceride were stable over time. Three patients demonstrated a loss of eGFR >15 mL/min·1.73 m from baseline. Three cases of upper respiratory infection and 2 cases of urinary tract infection were observed during the study. Patients who achieved complete remission had better renal function and lower baseline proteinuria than partial remission and nonresponder patients. Crescent formation in biopsy specimens was seen more often in nonresponder patients.Tacrolimus was safe and effective at lowering proteinuria in refractory IgAN patients. Lower baseline proteinuria and better renal function were associated with a higher probability of complete remission, while crescent formation was associated with a worse prognosis.

[IgA nephropathy]

IgA nephropathy is the most common form of primary glomerulonephritis worldwide and an important cause of chronic kidney disease and end-stage kidney failure. Its pathophysiology remains in part unsolved but it is recognized as an immune complex disease. Recent years have brought progress in the field through the discovery of several genetic susceptibility loci and the formulation of the multi-hit pathogenesis model. Presentation, clinical course and histology can be extremely variable, making any histological classification still difficult. Indeed, most therapeutic studies until now include patients based only on the severity of clinical criteria but the new classification of Oxford should change that. Only the management of patients with nephropathy with minimal change glomerular lesions and nephrotic syndrome, or extra-capillary glomerulonephritis and rapidly progressive renal failure, is consensual: Corticosteroids alone for the first and associated with immunosuppressive drugs for the latter. The recent Kidney Disease Improving Global Outcomes (KDIGO) consensus treatment guideline is still controversial, especially in light of the last clinical studies. Corticosteroid therapy can be discussed in patients with proteinuria greater than 1 g/day without renal failure. All IgA nephropathy patients should benefit from the global management of chronic glomerular disease, including a renin-angiotensin system blocker in the presence of hypertension or proteinuria.

Effect of low-dose valsartan on proteinuria in normotensive immunoglobulin A nephropathy with minimal proteinuria: a randomized trial

BACKGROUND/AIMS

Immunoglobulin A nephropathy (IgAN) is a generally progressive disease, even in patients with favorable prognostic features. In this study, we aimed to investigate the antiproteinuric effect and tolerability of low-dose valsartan (an angiotensin II receptor blocker) therapy in normotensive IgAN patients with minimal proteinuria of less than 0.5 to 1.0 g/day.

METHODS

Normotensive IgAN patients, who had persistent proteinuria with a spot urine protein-to-creatinine ratio of 0.3 to 1.0 mg/mg creatinine, were recruited from five hospitals and randomly assigned to either 40 mg of valsartan as the low-dose group or 80 mg of valsartan as the regular-dose group. Clinical and laboratory data were collected at baseline, and at 4, 8, 12, and 24 weeks after valsartan therapy.

RESULTS

Forty-three patients (low-dose group, n = 23; regular-dose group, n = 20) were enrolled in the study. Proteinuria decreased significantly not only in the regular-dose group but also in the low-dose group. The change in urine protein-to-creatinine ratio at week 24 was -41.3% ± 26.1% (p < 0.001) in the regular-dose group and -21.1% ± 45.1% (p = 0.005) in the low-dose group. In the low-dose group, blood pressure was constant throughout the study period, and there was no symptomatic hypotension. In the regular-dose group, blood pressure decreased at weeks 8 and 12. No significant change in glomerular filtration rate, serum creatinine level, or serum potassium level was observed during the study period.

CONCLUSIONS

Our results suggest that low-dose valsartan can significantly reduce proteinuria without causing any intolerability in normotensive IgAN patients with minimal proteinuria.

Continuation of immunosuppressive treatment may be necessary in IgA nephropathy patients with remission of proteinuria: Evaluation by repeat renal biopsy

The present study aimed to evaluate the effects of an individualized, low-dose multi-drug immunosuppressive regimen for the treatment of immunoglobulin A nephropathy (IgAN). A preliminary investigation of the course of IgAN following immunosuppressive treatment was conducted based on repeat renal biopsies. Clinical and pathological data of 17 patients with IgAN who received repeat renal biopsies were analyzed retrospectively. In addition to basic treatment, 16 patients regularly received an individualized low-dose immunosuppressive regimen according to their clinical manifestations and pathological patterns following the first biopsy. Clinical parameters, including 24-h urinary protein excretion and levels of serum albumin, uric acid and total cholesterol were collected. Glomerular deposits of IgA and C3, as well as the activity and chronicity indexes of renal lesions were evaluated by semi-quantitative methods. The 24-h urinary protein excretion of the patients decreased significantly from the first biopsy (2.53±2.17 g/day) to the repeated biopsy (0.26±0.55 g/day) (P<0.001). Deposits of IgA and C3 in the glomerulus were persistent, but were reduced in quantity at the second biopsy. Although active renal lesions were observed in the majority of patients, the activity index decreased significantly from 3.18±1.33 prior to therapy to 2.47±0.80 following therapy (P<0.05), while the chronicity index did not change significantly (2.59±2.00 versus 2.76±1.89, respectively). The individualized, low-dose multi-drug immunosuppressive regimen used in the present study significantly minimized proteinuria, stabilized renal function and alleviated histological lesions in patients with IgAN without causing overt adverse effects during the short-term follow-up. In addition to proteinuria, renal pathological changes should be appraised when considering the withdrawal of immunosuppressants from IgAN treatment.

Tacrolimus decreases albuminuria in patients with IgA nephropathy and normal blood pressure: a double-blind randomized controlled trial of efficacy of tacrolimus on IgA nephropathy

Background

Treatment remains uncertain for IgA nephropathy patients with mild to moderate proteinuria, for whom anti-hypertensive medication or the RAS blocker is not applicable due to low blood pressure.

Trial design

A double blinded randomized trial.

Methods

The anti-proteinuric effect of tacrolimus was explored for 40 biopsy-proven mild IgA nephropathies for 16 weeks. We randomly assigned patients either to receive tacrolimus or placebo with stratification by using a renin angiotensin system blocker. The primary outcome was the percentage change of final UACR compared to the baseline value (pcUACR).

Results

The mean value of pcUACR at 12-week and 16-week visits (primary outcome) was decreased more in the Tac group compared to the control group (–52.0±26.4 vs –17.3±29.3%, p = 0.001). At each visit, pcUACR was also decreased more in the Tac group compared to the control group. In the Tac group, the pcUACRs were –60.2±28.2%, –62.2±33.9%, –48.5±29.8%, and –55.5±24.0%, and, in the control group, –6.8±32.2%, –2.5±35.9%, –12.7±34.2%, and –21.9±30.6%, at 4-week, 8-week, 12-week, and 16-week visits, respectively. The pre-defined secondary outcomes were better in the Tac group compared to the control group. The frequency of decrease in pcUACR and percentage change of UPCR (pcUPCR) ≥50% at 16 weeks were 65.0% (13/20) and 55.0% (11/20)in the Tac group, and 25.0% (5/20) and 15.0% (3/20), in the control group, respectively (p = 0.025 for pcUACR and p = 0.019 for pcUPCR). However, tacrolimus wasn't effective with a dose of 0.05 mg/kg/day in patients taking ARB. The adverse events were tolerable.

Conclusion

Tacrolimus effectively reduced proteinuria in IgA nephropathy with normal blood pressure. This suggested that tacrolimus could be an alternative to corticosteroid and RAS blocker for IgA nephropathy patients who cannot endure anti-hypertensive medication.

Trial Registration

Clinicaltrial.gov NCT1224028

Cigarette smoking and progression of IgA nephropathy

BACKGROUND

Multiple community-based cohort studies of mainly middle-aged and elderly populations have shown that cigarette smoking is a risk factor for chronic kidney disease. However, little information is available about an effect of cigarette smoking on progression of primary kidney diseases, including immunoglobulin A (IgA) nephropathy.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

971 of 1,001 patients with a diagnosis of IgA nephropathy in 3 major nephrology centers in Osaka, Japan, between 1992 and 2005 who enrolled in the Study of Outcome and Practice Pattern of IgA Nephropathy (STOP-IgAN).

PREDICTORS

Smoking status and number of cigarettes smoked at the time of diagnosis using kidney biopsy. Dose-dependent associations between cigarette smoking and outcomes were assessed in multivariate Cox proportional hazards models. Significantly different clinical characteristics between non-/past and current smokers were controlled for using propensity score-based adjustment, stratification, and matching.

OUTCOMES

50% increase in serum creatinine level as primary outcome. A composite outcome of a 100% increase in serum creatinine level or end-stage renal disease (ESRD) and ESRD alone as secondary outcomes.

RESULTS

During the median 5.8 years (interquartile range, 2.6-10.2) of the observational period, 117 participants progressed to a 50% increase in serum creatinine level and 47 advanced to ESRD. Multivariate Cox proportional hazards models identified current smokers (HR, 2.03 [95% CI, 1.33-3.10] for primary outcome) and number of cigarettes at kidney biopsy (HR, 1.21 [95% CI, 1.06-1.39] per 10 cigarettes per day) as significant predictors of outcomes. Propensity score-based models confirmed these results. Tests for interaction showed that the association of current smoking with adverse outcomes was stronger in those with lower compared with higher estimated glomerular filtration rates.

LIMITATION

Baseline smoking status was not verified using biochemical tests. Smoking status during the observational period was unavailable.

CONCLUSIONS

Cigarette smoking, in a dose-dependent manner, was identified as a key prognostic factor in IgA nephropathy. Smoking cessation should be encouraged as part of the treatment for IgA nephropathy.

[Glomerulonephritis with IgA mesangial deposits]

IgA nephropathy is the primitive glomerulonephritis the most frequently encountered worldwide. In about one case out of three, it is responsible for the progression from progressive renal failure to end-stage renal failure. The pathophysiological mechanisms of this disease which is mediated by immune complexes remain unclear. The presentation, clinical progression and optical microscope aspect of the renal biopsy may widely vary, making any histological classification very difficult. Most therapeutic studies include the patients only on clinical criteria of severity. The only consensual management is that of patients with a nephropathy and mild glomerular lesions and a nephritic syndrome, or with an extracapillar glomerulonephritis and a rapidly progressive renal failure; corticoids are indicated in former cases while corticoids must be combined with immunosuppressive agents in the latter ones. Corticotherapy may be considered in patients with a proteinuria higher than 1g/day without renal failure. In any patient with primitive IgA nephropathy, the overall management used for chronic glomerulopathy must be initiated, including, in case of arterial hypertension or proteinuria, the renin-angiotensin system blockade.

Chronic kidney disease perspectives in Japan and the importance of urinalysis screening

There are racial differences in primary renal diseases for end-stage renal disease (ESRD) and the incidence and prevalence of cardiovascular disease (CVD). To reduce the number of patients with both ESRD and CVD, an effective screening method for CKD should be established. In Japan, screening with the urine dip-stick test for proteinuria has been used since 1972 targeting every child and worker and since 1983 for every resident over 40 years old. There are several reasons for continuing this screening program. First, the positive rate of proteinuria is high in the Japanese general population, especially subjects with neither hypertension nor diabetes. Most of these subjects have no symptoms, and the only sign of renal disease is asymptomatic urinary abnormalities. Second, the prevalence and incidence of glomerulonephritis, especially IgA nephropathy, are high in the Japanese and Asian races, and urinalysis is the only method for early detection of chronic glomerulonephritis. Third, 10-year survival of the ESRD patients due to glomerulonephritis was approximately twice that of ESRD patients due to diabetes and nephrosclerosis. Consequently, reducing the incidence of ESRD due to glomerulonephritis is one of the best ways to reduce the prevalence of ESRD. Furthermore, higher incidence of ESRD in Asian races than in Caucasians was reported. Proteinuria is known to be the best predictor for reducing renal function, and the urine dip-stick test for proteinuria is less expensive and is cost-effective. For an effective screening strategy to reduce the ESRD population in Japanese and Asians, universal screening with the urine dip-stick test for proteinuria could be one solution.

Remission of proteinuria improves prognosis in IgA nephropathy

Proteinuria has been shown to be an adverse prognostic factor in IgA nephropathy. The benefit of achieving a partial remission of proteinuria, however, has not been well described. We studied 542 patients with biopsy-proven primary IgA nephropathy in the Toronto Glomerulonephritis Registry and found that glomerular filtration rate (GFR) declined at -0.38 +/- 0.61 ml/min per 1.73 m2/mo overall, with 30% of subjects reaching end-stage renal disease. Multivariate analysis revealed that proteinuria during follow-up was the most important predictor of the rate of GFR decline. Among the 171 patients with <1 g/d of sustained proteinuria, the rate of decline was 90% slower than the mean rate. The rate of decline increased with the amount of proteinuria, such that those with sustained proteinuria >3 g/d (n = 121) lost renal function 25-fold faster than those with <1 g/d. Patients who presented with > or =3 g/d who achieved a partial remission (<1 g/d) had a similar course to patients who had < or =1 g/d throughout, and fared far better than patients who never achieved remission. These results underscore the relationship between proteinuria and prognosis in IgA nephropathy and establish the importance of remission.

IgA glomerulonephritis: beyond angiotensin-converting enzyme inhibitors

IgA glomerulonephritis accounts for 25-50% of renal biopsy diagnoses. About 25-50% of patients progress to end-stage renal disease within 20 years of diagnosis. Angiotensin-converting enzyme inhibitors and angiotensin II type I receptor blockers slow progression of IgA nephropathy (IgAN); however, as drugs of this class are not IgAN specific and are therefore unlikely to alter significantly its natural course, many other therapeutic approaches have been proposed. Most have been tested in a relatively small number of patients and have not yet proven to be effective in the long term. Conflicting and variable data, and a lack of long-term prospective randomized studies, mean that most treatments cannot be recommended as standard therapy for IgAN. Steroids seem to be the best treatment for patients with proteinuria, as drugs in this class ameliorate this symptom and protect against deterioration of renal function. Combined treatment with corticosteroids and cytotoxic drugs has yielded interesting results in several studies, especially in progressive patients with severe IgAN. In this review, we critically analyze the data on these treatments.

Impact of Hypertension and Hypertension-Related Vascular Lesions in IgA Nephropathy

It remains poorly understood whether vascular pathology plays an important role in the progression of renal parenchymal disease in humans. Moreover, in the case of hypertensive patients with mild proteinuria, nephrologists tend to make a diagnosis of benign nephrosclerosis without renal biopsy. Among 172 patients who were treated at our hospital for biopsy-proven IgA nephropathy, we performed quantitative histopathological analysis in 38 patients with mild proteinuria of less than 0.5 g/day. We related these histopathological parameters with clinical data at biopsy and also with follow-up data. The percentage of glomeruli showing global sclerosis exceeded 10% of total glomeruli in 15 of the patients (39.5%) and exceeded 20% in 9 (23.7%). Arteriosclerosis and tubulointerstitial changes significantly correlated with glomerular sclerosis, but mesangial cell proliferation did not. Among the 38 patients, the 12 with hypertension showed more severe glomerular sclerosis, tubulointerstitial changes and arteriosclerosis compared with the 26 without hypertension, but the mesangial cell proliferation was identical between the two groups. Stepwise multiple regression analysis revealed that hypertension and urinary protein excretion (UPE) were independent risk factors for arteriosclerosis. The follow-up data of a mean period of 27.6 months showed that 9 of the 38 patients (23.7%) had an increase in UPE. Hypertension, arteriosclerosis, age, and UPE at biopsy were selected as the important risk factors for an increase in UPE in the follow-up. Our results provide not only clinical but histopathological evidence that hypertension affects the prognosis of mild proteinuric nephropathy through vascular lesions.

The glomerulo-tubular junction: a target in renal diseases

Both global and segmental glomerulopathies may damage specific areas of the renal glomerulus. Diseases associated with glomerular hyperperfusion cause lesions at the vascular pole, while diseases associated with proteinuria often damage the tubular pole. Atubular glomeruli are now known to be plentiful in a variety of common renal diseases. These glomeruli are disconnected from their tubule at the tubular pole and therefore cannot participate in the production of urine. It is widely believed that the disconnection is a result of external compression by periglomerular fibrosis. However, the variable anatomy and cell populations within both the glomerulus and the beginning of the proximal tubule at the glomerulo-tubular junction may also have important roles to play in the response to damage at this sensitive site of the nephron.