Predictors of relapse and treatment resistance in antineutrophil cytoplasmic antibody-associated small-vessel vasculitis

BACKGROUND

Predictors of treatment resistance and relapse have not been well described in antineutrophil cytoplasmic antibody (ANCA)-associated small-vessel vasculitis.

OBJECTIVE

To identify clinical, pathologic, and serologic predictors of treatment resistance and relapse in a community-based cohort of patients with ANCA-associated vasculitis.

DESIGN

Cohort of patients identified at or near the time of biopsy diagnosis and followed as clinically indicated.

SETTING

The Glomerular Disease Collaborative Network.

PATIENTS

350 patients who received a new diagnosis of ANCA-associated vasculitis between 1985 and 2003 and were followed for a median of 49 months.

MEASUREMENTS

Patients were categorized according to whether they had antiproteinase-3 (anti-PR3) antibodies or antimyeloperoxidase (anti-MPO) antibodies. Organ involvement was determined by biopsy or by well-defined clinical criteria. Treatment resistance was defined as progressive decline in kidney function with active urine sediment or the persistence or appearance of extrarenal manifestations. Relapse was defined as the time to the resurgence of vasculitic symptoms.

RESULTS

Treatment resistance affected 23% of 334 treated patients and was associated with female sex, black ethnicity, and presentation with severe kidney disease (odds ratio per serum creatinine elevation of 100 micromol/L [1.13 mg/dL], 1.28 [95% CI, 1.16 to 1.39]). The following factors were associated with relapse in 258 (77%) patients who attained remission: seropositivity for anti-PR3 antibodies (hazard ratio, 1.87 [CI, 1.11 to 3.14]) and disease of the lung (hazard ratio, 1.71 [CI, 1.04 to 2.81]) or upper respiratory tract (hazard ratio, 1.73 [CI, 1.04 to 2.88]). Relapses occurred in 26% of patients with no risk factors versus 73% of patients with all 3 risk factors (hazard ratio, 3.7 [CI, 1.4 to 9.7]). Among 143 patients attaining remission who subsequently stopped all immunosuppressant therapy, relapse rates were similar for those who had received cyclophosphamide therapy for 6 months or less (34%) compared with those treated for a longer duration (35%), even after adjusting for risk factors for relapse (hazard ratio, 1.41 [CI, 0.80 to 2.50]).

LIMITATIONS

The cohort mostly included patients with biopsy-proven kidney disease. Patients were not followed with uniform treatment protocols, and only limited information about their clinical course before diagnosis was available.

CONCLUSIONS

Female or black patients, or those with severe kidney disease, may be resistant to initial treatment more often than other patients with ANCA-associated small-vessel vasculitis. Increased risk for relapse appears to be related to the presence of lung or upper airway disease and anti-PR3 antibody seropositivity.

Classification of antineutrophil cytoplasmic autoantibody vasculitides: the role of antineutrophil cytoplasmic autoantibody specificity for myeloperoxidase or proteinase 3 in disease recognition and prognosis

OBJECTIVE

To compare the usefulness of 3 currently used classification systems in predicting the outcomes of treatment resistance, disease relapse, end-stage renal disease (ESRD), and death in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

Three classification systems were applied to 502 patients with biopsy-proven AAV: 1) the Chapel Hill Consensus Conference (CHCC) definition with categories for granulomatosis with polyangiitis (GPA) (Wegener's), microscopic polyangiitis (MPA), and kidney-limited disease; 2) the European Medicines Agency (EMA) system with categories for GPA and MPA; and 3) classification based on ANCA with specificity for myeloperoxidase (MPO ANCA) versus ANCA with specificity for proteinase 3 (PR3 ANCA). Outcomes included treatment resistance, relapse, ESRD, and death. Proportional hazards models were compared between systems using an information-theoretic approach to rank models by predictive fit. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) and P values are reported.

RESULTS

ANCA specificity was predictive of relapse, with PR3 ANCA-positive patients almost twice as likely to relapse as those with MPO ANCA (HR 1.89 [95% CI 1.33-2.69], P = 0.0004), and ANCA specificity had the best predictive model fit (model rank 1) compared to the CHCC and EMA systems. The CHCC and EMA systems did not predict relapse. By ANCA specificity, categories of GPA, MPA, and kidney-limited disease did not distinguish differences in probability of relapse-free survival. None of the systems predicted treatment resistance, ESRD, or death.

CONCLUSION

ANCA specificity independently predicts relapse among patients with AAV with renal disease. Classification and diagnostic systems that incorporate ANCA specificity, such as PR3 ANCA-positive MPA and MPO ANCA-positive MPA, provide a more useful tool than the clinical pathologic category alone for predicting relapse.

Design of the Nephrotic Syndrome Study Network (NEPTUNE) to evaluate primary glomerular nephropathy by a multidisciplinary approach

The Nephrotic Syndrome Study Network (NEPTUNE) is a North American multicenter collaborative consortium established to develop a translational research infrastructure for nephrotic syndrome. This includes a longitudinal observational cohort study, a pilot and ancillary study program, a training program, and a patient contact registry. NEPTUNE will enroll 450 adults and children with minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy for detailed clinical, histopathological, and molecular phenotyping at the time of clinically indicated renal biopsy. Initial visits will include an extensive clinical history, physical examination, collection of urine, blood and renal tissue samples, and assessments of quality of life and patient-reported outcomes. Follow-up history, physical measures, urine and blood samples, and questionnaires will be obtained every 4 months in the first year and biannually, thereafter. Molecular profiles and gene expression data will be linked to phenotypic, genetic, and digitalized histological data for comprehensive analyses using systems biology approaches. Analytical strategies were designed to transform descriptive information to mechanistic disease classification for nephrotic syndrome and to identify clinical, histological, and genomic disease predictors. Thus, understanding the complexity of the disease pathogenesis will guide further investigation for targeted therapeutic strategies.

Prognostic markers in patients with antineutrophil cytoplasmic autoantibody-associated microscopic polyangiitis and glomerulonephritis

The purpose of this study was to determine the prognostic value of clinical, laboratory, and pathologic features at the time of presentation on patient and renal survival in patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated microscopic polyangiitis and glomerulonephritis (excluding Wegener's granulomatosis). One hundred seven ANCA-positive patients with necrotizing and crescentic glomerulonephritis, including 69 with evidence for microscopic polyangiitis, were evaluated for this study. The relative risk of death was calculated for the following potential prognostic indicators: (1) ANCA pattern; (2) pulmonary hemorrhage at onset; (3) presence of extrarenal manifestations versus renal limited disease; and (4) treatment with corticosteroids and cyclophosphamide (intravenous or oral), compared with corticosteroids alone. Cox's proportional hazard model was used to assess the predictive value of the following variables on renal survival: (1) age; (2) race; (3) pulmonary symptoms at onset of disease; (4) renal pathology; (5) ANCA pattern; and (6) peak serum creatinine values obtained near the time of renal biopsy. Patients were followed prospectively for 2.5 yr (range, 5 days to 12 yr 2 months). There were 12 disease-related deaths and 46 patients who reached ESRD. The relative risk (and 95% confidence interval) of patient death was 8.65 (3.36, 22.2) times greater in patients who presented with pulmonary hemorrhage, and 3.78 (1.22, 11.70) times greater in patients with cytoplasmic ANCA compared to those with perinuclear ANCA. The relative risk of pulmonary hemorrhage was no different by ANCA pattern. The risk of death was 5.56 times lower in the cyclophosphamide-treated patients versus those treated with corticosteroids alone. The predictors of renal survival were entry serum creatinine value (P = 0.0002), race (African Americans having a worse outcome compared with Caucasians, P = 0.0008), and the presence of arterial sclerosis on kidney biopsy (P = 0.0076) when controlling for age, ANCA pattern, microscopic polyangiitis versus glomerulonephritis alone, and pulmonary involvement. Pathology indices such as glomerular necrosis, glomerular crescents, glomerular sclerosis, and interstitial sclerosis were not predictive of renal survival when controlling for entry serum creatinine value, race, and arterial sclerosis. However, in the subgroup of patients with a peak creatinine value of < or = 3.0 mg/dL (N = 29), increased interstitial sclerosis was a predictor of a poor renal outcome (P = 0.04).

Rituximab therapy in idiopathic membranous nephropathy: a 2-year study

BACKGROUND AND OBJECTIVES

It was postulated that in patients with membranous nephropathy (MN), four weekly doses of Rituximab (RTX) would result in more effective B cell depletion, a higher remission rate, and maintaining the same safety profile compared with patients treated with RTX dosed at 1 g every 2 weeks. This hypothesis was supported by previous pharmacokinetic (PK) analysis showing that RTX levels in the two-dose regimen were 50% lower compared with nonproteinuric patients, which could potentially result in undertreatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty patients with MN and proteinuria >5 g/24 h received RTX (375 mg/m(2) × 4), with re-treatment at 6 months regardless of proteinuria response. PK analysis was conducted simultaneously with immunological analyses of T and B cells to ascertain the effect of RTX on lymphocyte subpopulations.

RESULTS

Baseline proteinuria of 11.9 g/24 h decreased to 4.2 and 2.0 g/24 h at 12 and 24 months, respectively, whereas creatinine clearance increased from 72.4 ml/min per 1.73 m(2) at baseline to 88.4 ml/min per 1.73 m(2) at 24 months. Of 18 patients who completed 24-month follow-up, 4 are in complete remission, 12 are in partial remission, 1 has a limited response, and 1 patient relapsed. Serum RTX levels were similar to those obtained with two doses of RTX.

CONCLUSIONS

Four doses of RTX resulted in more effective B cell depletion, but proteinuria reduction was similar to RTX at 1 g every 2 weeks. Baseline quantification of lymphocyte subpopulations did not predict response to RTX therapy.

Treatment response and relapse in antineutrophil cytoplasmic autoantibody-associated microscopic polyangiitis and glomerulonephritis

In this study, the rate of remission, relapse, and treatment resistance in 107 patients with microscopic polyangiitis and necrotizing and crescentic glomerulonephritis associated with antineutrophil cytoplasmic autoantibodies were assessed. Patients with Wegener's granulomatosis were excluded. Prospective criteria were identified to assess remission, relapse, and resistant disease. Ninety-seven of the 107 patients received treatment with corticosteroids (N = 25) or with cyclophosphamide and corticosteroids (N = 72). Of these patients, 75 (77.3%) went into remission (complete remission, N = 61; remission on therapy, N = 14). Of the 75 responders, 32 patients (43%) remained in long-term remission, for a mean follow-up of 44 +/- 29 months; 15 patients (20%) progressed to ESRD without signs of relapse, for a mean of 21.4 +/- 22.8 months after the end of treatment; 6 patients died. Twenty-two of the 75 patients who initially responded to treatment (29%) suffered a relapse that occurred within 18 months of the end of therapy and usually affected the same organ systems as on initial presentation. There was a significant difference in the remission rate between the corticosteroid-treated patients and the cyclophosphamide-treated patients (56% versus 84.7%, P = 0.003), and the cyclophosphamide-treated patients had three times less risk of experiencing a relapse than did corticosteroid-treated patients (0.31, 95% Cl = (0.12, 0.84)). Seventy-seven percent (17 of 22 patients) of treatment resistance occurred in patients who presented with fulminant disease or advanced and severe renal disease. It was concluded that most patients with microscopic polyangiitis or necrotizing and crescentic glomerulonephritis achieve remission with therapy. Relapses occur in 29% of patients and generally respond to retreatment. Initial treatment with cyclophosphamide and corticosteroids rather than corticosteroids alone results in a lower frequency of relapse. Even patients who require dialysis at presentation may benefit from treatment, however, patients who are not treated until the disease process is life-threatening may die before induction therapy is complete, indicating the continued need for early diagnosis and therapy.

ANCA Glomerulonephritis and Vasculitis

ANCA vasculitis has an associated autoimmune response that produces ANCAs that induce distinct pathologic lesions. Pauci-immune necrotizing and crescentic GN is a frequent component of ANCA vasculitis. ANCA vasculitis is associated with ANCA specific for myeloperoxidase (MPO-ANCA) or proteinase 3 (PR3-ANCA). A diagnosis of ANCA vasculitis should always specify the serotype as MPO-ANCA positive, PR3-ANCA positive, or ANCA-negative. To fully characterize a patient, the serotype also should be accompanied by the clinicopathologic variant if this can be determined: microscopic polyangiitis, granulomatosis with polyangiitis (Wegener), eosinophilic granulomatosis with polyangiitis (Churg-Strauss), or renal-limited vasculitis. ANCA vasculitis is most prevalent in individuals >50 years old. There are racial/ethnic and geographic influences on the prevalence, serotype frequencies, and clinicopathologic phenotypes. There is clinical, in vitro, and animal model evidence that ANCAs cause disease by activating neutrophils to attack small vessels. Immunomodulatory and immunosuppressive therapies are used to induce remission, maintain remission, and treat relapses. Over recent years, there have been major advances in optimizing treatment by minimizing toxic therapy and utilizing more targeted therapy.

Predictors of treatment resistance and relapse in antineutrophil cytoplasmic antibody-associated small-vessel vasculitis: comparison of two independent cohorts

OBJECTIVE

Predictors of treatment resistance and relapse have been identified in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis in the Glomerular Disease Collaborative Network (GDCN) in the southeastern US. This study was undertaken to evaluate the applicability of those predictors in an independent cohort followed up by the French Vasculitis Study Group.

METHODS

Predictors of treatment resistance were evaluated using logistic regression models and reported as odds ratios (ORs) with 95% confidence intervals (95% CIs). Predictors of relapse were evaluated using Cox proportional hazards models and reported as hazard ratios (HRs) with 95% CIs. Models were controlled for age, sex, race, baseline serum creatinine level, and cyclophosphamide therapy.

RESULTS

The French cohort (n = 434) and the GDCN cohort (n = 350) had similar median followup periods (44 months versus 45 months) and initial percentages of patients taking cyclophosphamide (82% versus 78%). The French cohort included more patients with proteinase 3 (PR3) ANCA (58% versus 40%), lung involvement (58% versus 49%), and upper respiratory tract involvement (62% versus 31%). Of the predictors of treatment resistance in the GDCN cohort (female sex, African American race, presence of myeloperoxidase ANCA, elevated creatinine level, and age), only age predicted treatment resistance in the French cohort (OR 1.32 per 10 years [95% CI 1.05-1.66]). Predictors of relapse in the GDCN cohort were PR3 ANCA (HR 1.77 [95% CI 1.11-2.82]), lung involvement (HR 1.68 [95% CI 1.10-2.57), and upper respiratory tract involvement (HR 1.58 [95% CI 1.00-2.48]), while predictors in the French cohort were PR3 ANCA (HR 1.66 [95% CI 1.15-2.39]) and lung involvement (HR 1.56 [95% CI 1.11-2.20]), but not upper respiratory tract involvement (HR 0.96 [95% CI 0.67-1.38]).

CONCLUSION

Our findings indicate that older age is a predictor of treatment resistance, and that PR3 ANCA and lung involvement are predictors of relapse in both cohorts. Discrepancies in predictors of treatment tract resistance may reflect differences in access to care, and differences in predictors of relapse may reflect variations in disease expression.

Epitope specificity determines pathogenicity and detectability in ANCA-associated vasculitis

Anti-neutrophil cytoplasmic antibody-associated (ANCA-associated) small vessel necrotizing vasculitis is caused by immune-mediated inflammation of the vessel wall and is diagnosed in some cases by the presence of myeloperoxidase-specific antibodies (MPO-ANCA). This multicenter study sought to determine whether differences in ANCA epitope specificity explain why, in some cases, conventional serologic assays do not correlate with disease activity, why naturally occurring anti-MPO autoantibodies can exist in disease-free individuals, and why ANCA are undetected in patients with ANCA-negative disease. Autoantibodies from human and murine samples were epitope mapped using a highly sensitive epitope excision/mass spectrometry approach. Data indicated that MPO autoantibodies from healthy individuals had epitope specificities different from those present in ANCA disease. Importantly, this methodology led to the discovery of MPO-ANCA in ANCA-negative disease that reacted against a sole linear sequence. Autoantibodies against this epitope had pathogenic properties, as demonstrated by their capacity to activate neutrophils in vitro and to induce nephritis in mice. The confounder for serological detection of these autoantibodies was the presence of a fragment of ceruloplasmin in serum, which was eliminated in purified IgG, allowing detection. These findings implicate immunodominant epitopes in the pathology of ANCA-associated vasculitis and suggest that autoantibody diversity may be common to other autoimmune diseases.

Management and treatment of glomerular diseases (part 1): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

The Kidney Disease: Improving Global Outcomes (KDIGO) initiative organized a Controversies Conference on glomerular diseases in November 2017. The conference focused on the 2012 KDIGO guideline with the aim of identifying new insights into nomenclature, pathogenesis, diagnostic work-up, and, in particular, therapy of glomerular diseases since the guideline's publication. It was the consensus of the group that most guideline recommendations, in particular those dealing with therapy, will need to be revisited by the guideline-updating Work Group. This report covers general management of glomerular disease, IgA nephropathy, and membranous nephropathy.

Proteinuria Reduction as a Surrogate End Point in Trials of IgA Nephropathy

IgA nephropathy (IgAN) is an important cause of ESKD for which there are no approved therapies. A challenge for evaluating treatments for IgAN is the usual long time course for progression to ESKD. The aim of this Kidney Health Initiative project was to identify surrogate end points that could serve as reliable predictors of a treatment's effect on long-term kidney outcomes in IgAN and be used as a basis for approval. Proteinuria was identified as the most widely recognized and well studied risk factor for progression to ESKD in IgAN. The workgroup performed a critical review of the data on proteinuria reduction as a surrogate end point for a treatment's effect on progression to ESKD in IgAN. Epidemiologic data indicate a strong and consistent relationship between the level and duration of proteinuria and loss of kidney function. Trial-level analyses of data from 13 controlled trials also show an association between treatment effects on percent reduction of proteinuria and treatment effects on a composite of time to doubling of serum creatinine, ESKD, or death. We conclude that data support the use of proteinuria reduction as a reasonably likely surrogate end point for a treatment's effect on progression to ESKD in IgAN. In the United States, reasonably likely surrogate end points can be used as a basis for accelerated approval of therapies intended to treat serious or life-threatening conditions, such as IgAN. The clinical benefit of products approved under this program would need to be verified in a postmarketing confirmatory trial.

Mycophenolate mofetil therapy in lupus nephritis: clinical observations

Controlled clinical trials in renal transplantation have demonstrated that mycophenolate mofetil is well tolerated and has lower renal transplant rejection rates than azathioprine regimens. This study reports on the clinical experiences at two institutions with mycophenolate mofetil (MMF) for severe lupus nephritis. Twelve patients with relapsing or resistant nephritis previously treated with cyclophosphamide therapy and one patient who refused cyclophosphamide as initial therapy for diffuse proliferative nephritis but accepted MMF were included. During combined MMF/prednisone therapy, serum creatinine values remained normal or declined from elevated values: mean change in serum creatinine was -0.26+/-0.46 microM/L, P = 0.039. Proteinuria significantly decreased: mean change in urine protein-to-creatinine ratios was -2.53+/-3.76, P = 0.039. Decreased serum complement component C3 and elevated anti-double-stranded DNA antibody levels at baseline improved in some, but not all, patients. The mean initial dose of MMF was 0.92 g/d (range, 0.5 to 2 g/d). The mean duration of therapy was 12.9 mo (range, 3 to 24 mo). Adverse events included herpes simplex stomatitis associated with severe leukopenia (n = 1), asymptomatic leukopenia (n = 2), nausea/ diarrhea (n = 2), thinning of scalp hair (n = 1), pancreatitis (n = 1), and pneumonia without leukopenia (n = 1). Recurrence of the pancreatitis led to discontinuation of MMF in this patient; all other adverse events resolved with dose reduction. It is concluded that MMF is well tolerated and has possible efficacy in controlling major renal manifestations of systemic lupus erythematosus. Controlled clinical trials are needed to define the role of MMF in the management of lupus nephritis.

Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome : workshop recommendations

Management of idiopathic glomerular disease associated with nephrotic syndrome (INS) remains controversial and one of the most complex areas relates to utilization of the drug cyclosporin. This is despite its demonstrated effectiveness in several histologic types of the INS in randomized controlled trials. Cyclosporin is effective in inducing remission of proteinuria in approximately 80% of steroid-sensitive cases of minimal change disease (MCD). Cyclosporin is also effective in both the induction of remission and long-term preservation of renal function in steroid-dependent/-resistant MCD and steroid-resistant focal segmental glomerulosclerosis (FSGS). The overall response rate in FSGS is lower than in MCD, and long-term therapy (>12 months) may be required to both achieve remission and sustain it. Cyclosporin therapy is also of benefit in reducing proteinuria in 70-80% of patients with steroid-resistant membranous nephropathy (MGN). In MGN, the maximum benefit is often delayed compared to MCD (>12 weeks). Cyclosporin is generally well tolerated and safe. The major concern remains the nephrotoxicity, but with careful monitoring of the patient's renal function; minimizing the maintenance dose and utilizing repeat renal biopsy in those receiving long-term therapy, this risk can be minimized. The algorithms have been developed derived from the best evidence in the literature in each of the histologic types to help provide a guide to the integration of cyclosporin into the management of INS for the practicing nephrologist.

Recurrent ANCA-associated small vessel vasculitis after transplantation: A pooled analysis

BACKGROUND

Recurrent antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis (ANCA-SVV) after renal transplantation has been described in case series. However, general information regarding the frequency, character, and predictors of recurrent disease after transplantation is currently lacking. We considered the rate of relapse, whether a positive ANCA at the time of transplantation predicted relapse, and whether cyclosporine A prevented recurrent disease.

METHODS

We performed a pooled analysis of published data, added to the experience at the Universities of North Carolina (14 patients) and Lund, Sweden (11 patients). To avoid reporting bias, only case series were included for analysis. Subgroup analysis was performed by disease category (Wegener's granulomatosis, microscopic polyangiitis, or necrotizing crescentic glomerulonephritis) and ANCA staining pattern.

RESULTS

ANCA-SVV recurred in 17.3% of all patients (N = 127), in 20% of cyclosporine A-treated patients (N = 85), and in 25.6% of patients with circulating ANCA at the time of transplantation (N = 39). There was no statistically significant difference in the relapse rate between patients treated and those not treated with cyclosporine A (P = 0.45), between those with and without circulating ANCA at the time of transplant (P = 0.75), or between patients with Wegener's granulomatosis and those with microscopic polyangiitis or necrotizing crescentic glomerulonephritis alone (P = 0.62).

CONCLUSION

There is a substantial relapse rate in the ANCA-SVV population. Therapy with cyclosporine A does not protect against recurrent ANCA-SVV, and the presence of a positive ANCA at the time of transplantation does not preclude transplantation. These conclusions must be substantiated with a prospective study of renal transplantation in patients with ANCA-SVV so as to optimize their management.

Silica exposure in anti-neutrophil cytoplasmic autoantibody-associated glomerulonephritis and lupus nephritis

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated small-vessel vasculitis (SVV) and systemic lupus erythematosus (SLE) are rare diseases with unknown causes. Silica dust exposure has been suggested to be an environmental factor that may increase the risk of developing these and other autoimmune disorders. This is a report of two case-control studies to determine whether silica dust exposure is independently associated with ANCA-SVV with glomerulonephritis and SLE nephritis. Patients were screened through a collaborative network of 225 private practice and university nephrologists (the Glomerular Disease Collaborative Network). Patients with ANCA-SVV or SLE, all with biopsy-proven renal involvement, were included. Control subjects were patients without ANCA-SVV or SLE who had been referred to the same renal clinics and were matched for gender, race, and age (within 5 yr). Exposures to silica, exposures to other environmental agents, and smoking histories were evaluated using a self-administered questionnaire. Enrollment consisted of 65 patients with ANCA-SVV and 51 patients with SLE nephritis. Silica dust exposure was reported by 46% of patients with ANCA-SVV, compared with 20% of control subjects (P = 0.001). The odds ratio of silica dust exposure was 4.4 times greater for patients with ANCA-SVV, compared with control subjects (95% confidence interval, 1.36 to 13.4; P = 0.013). The odds ratios for silica dust exposure were similar for patients with ANCA-SVV with lung or sinus vasculitis (odds ratio, 4.5; 95% confidence interval, 0.99 to 20.83; P = 0.054) and those without lung or sinus vasculitis (odds ratio, 4.7; 95% confidence interval, 1.34 to 16.24; P = 0.016). Silica dust exposure was reported by 12% of patients with SLE nephritis, compared with 25% of control subjects (P = 0.047). The odds ratio for exposure to silica dust was not statistically different for patients with SLE nephritis, compared with control subjects (odds ratio, 0.001; 95% confidence interval, <0.01 to >100; P = 0.993). Activities and environments known to cause high levels of exposure to silica dust were associated with ANCA-SVV but not with SLE nephritis.

Venous thromboembolism in patients with membranous nephropathy

BACKGROUND AND OBJECTIVES

The aims of this study were to determine the frequency of venous thromboembolic events in a large cohort of patients with idiopathic membranous nephropathy and to identify predisposing risk factors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied patients with biopsy-proven membranous nephropathy from the Glomerular Disease Collaborative Network (n=412) and the Toronto Glomerulonephritis Registry (n=486) inception cohorts. The cohorts were pooled after establishing similar baseline characteristics (total n=898). Clinically apparent and radiologically confirmed venous thromboembolic events were identified. Potential risk factors were evaluated using multivariable logistic regression models.

RESULTS

Sixty-five (7.2%) subjects had at least one venous thromboembolic event, and this rate did not differ significantly between registries. Most venous thromboembolic events occurred within 2 years of first clinical assessment (median time to VTE = 3.8 months). After adjusting for age, sex, proteinuria, and immunosuppressive therapy, hypoalbuminemia at diagnosis was the only independent predictor of a venous thromboembolic event. Each 1.0 g/dl reduction in serum albumin was associated with a 2.13-fold increased risk of VTE. An albumin level <2.8 g/dl was the threshold below which risk for a venous thromboembolic event was greatest.

CONCLUSIONS

We conclude that clinically apparent venous thromboembolic events occur in about 7% of patients with membranous nephropathy. Hypoalbuminemia, particularly <2.8 g/dl, is the most significant independent predictor of venous thrombotic risk.

Long-term glycemic control measurements in diabetic patients receiving hemodialysis

Cardiovascular morbidity is increased in patients with diabetes mellitus and there is a great prevalence of diabetes and cardiovascular disease among patients with end-stage renal disease (ESRD). Control of glycemia can decrease cardiovascular and end-organ damage. Because the validity of glycemic control tests have not been rigorously studied in patients with ESRD, we evaluated the value of various measures in these patients. The overall clinical goal was to investigate whether hemoglobin A1C (A1C) accurately reflects actual glycemic control as compared with other measures in light of the importance of attaining appropriately controlled blood glucose (BG). The commonly used tests of total glycated hemoglobin (GHb) and A1C may be unreliable in patients with ESRD because of the presence of anemia, shortened red blood cell (RBC) survival, and assay interferences from uremia. The primary aim of this study was to assess the relationship of capillary BG measurements to A1C, GHb, total glycated plasma proteins (GPP), and fructosamine (Fr) in diabetic patients receiving hemodialysis. Twenty-three patients were instructed to obtain BG evaluations twice daily for 7 days by using the Elite glucometer (Bayer Corporation, Elkhart, IN). These determinations included 6 fasting, 6 preprandial, and 3 separate 2-hour postprandial levels. Blood was obtained on day 7 for measurement of A1C, GHb, GPP, and Fr. A1C was analyzed by an immunoassay, GPP and GHb were assayed by affinity high-performance liquid chromatography (HPLC), and Fr by automated nitroblue colorimetric assay. Scatter plots were generated by plotting the average BG versus A1C, GHb, GPP, or Fr. Linear regression was performed for each plot showing the following relationships: A1C = 0.0174 (BG) + 4.76 (r = 0.58; P < 0.05): GHb = 0.0371 (BG) + 3.57 (r = 0.584; P < 0.05): GPP = 0.0083 (BG) + 26.13 (r = 0.065; P = 0.77): Fr = 0.6865 (BG) + 250 (r = 0.345; P = 0.11). Despite anemia and shortened RBC lifespan in patients with ESRD, A1C in the range of 6% to 7% estimates glycemic control similarly to patients without severe renal impairment. A1C values above 7.5% may overestimate hyperglycemia in patients with ESRD. Thus, diabetic patients receiving hemodialysis may have long-term BG that are more properly controlled than previously determined, reducing their risks of the macro- and microvascular complications of diabetes mellitus.

Predictors of treatment outcomes in ANCA-associated vasculitis with severe kidney failure

BACKGROUND AND OBJECTIVES

In ANCA-associated GN, severe renal dysfunction portends a poor prognosis for renal recovery and patient survival. This study evaluated the prognostic factors affecting renal and patient outcomes in patients presenting with severe kidney failure to guide immunosuppressive therapy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study retrospectively evaluated clinical and histopathologic characteristics of 155 patients who underwent biopsy between October 1985 and February 2011 (median eGFR at presentation, 7.1 ml/min per 1.73 m(2); 87% required hemodialysis), all treated with immunosuppressive medications. Three outcomes of interest were measured: patient survival, renal survival, and treatment response (defined as dialysis-free survival without active vasculitis by 4 months after biopsy). Competing risk, Cox, and logistic regression analyses were conducted for each outcome measure.

RESULTS

Within 4 months after biopsy, treatment response was attained in 51% of patients, 35% remained on dialysis, and 14% died. In a competing risk analysis, estimated cumulative incidence rates of ESRD and disease-related mortality were 26% and 17% at 1 year and 32% and 28% at 5 years, respectively. Cyclophosphamide therapy and treatment response by 4 months were independently associated with patient and renal survival, adjusting for the percentage of normal glomeruli, histopathologic chronicity index score, and baseline clinical characteristics. Only 5% of patients still dialysis dependent at 4 months subsequently recovered renal function. Low chronicity index score (odds ratio [OR], 1.16; 95% confidence interval [95% CI], 1.04 to 1.30, per unit decrease) and baseline eGFR>10 ml/min per 1.73 m(2) (OR, 2.77; 95% CI, 1.09 to 7.01) were significantly associated with treatment response by 4 months. Among cyclophosphamide-treated patients, the likelihood of treatment response was >14% even with highest chronicity index score and eGFR<10 ml/min per 1.73 m(2).

CONCLUSIONS

Although low baseline renal function and severe renal scarring are associated with lower treatment response rate, no "futility" threshold could be identified. Conversely, continued immunosuppressive therapy beyond 4 months is unlikely to benefit patients who remain dialysis dependent.

Management and treatment of glomerular diseases (part 2): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

In November 2017, the Kidney Disease: Improving Global Outcomes (KDIGO) initiative brought a diverse panel of experts in glomerular diseases together to discuss the 2012 KDIGO glomerulonephritis guideline in the context of new developments and insights that had occurred over the years since its publication. During this KDIGO Controversies Conference on Glomerular Diseases, the group examined data on disease pathogenesis, biomarkers, and treatments to identify areas of consensus and areas of controversy. This report summarizes the discussions on primary podocytopathies, lupus nephritis, anti-neutrophil cytoplasmic antibody-associated nephritis, complement-mediated kidney diseases, and monoclonal gammopathies of renal significance.

Rituximab as therapy to induce remission after relapse in ANCA-associated vasculitis

OBJECTIVES

Evaluation of rituximab and glucocorticoids as therapy to induce remission after relapse in ANCA-associated vasculitis (AAV) in a prospective observational cohort of patients enrolled into the induction phase of the RITAZAREM trial.

METHODS

Patients relapsing with granulomatosis with polyangiitis or microscopic polyangiitis were prospectively enrolled and received remission-induction therapy with rituximab (4×375 mg/m2) and a higher or lower dose glucocorticoid regimen, depending on physician choice: reducing from either 1 mg/kg/day or 0.5 mg/kg/day to 10 mg/day by 4 months. Patients in this cohort achieving remission were subsequently randomised to receive one of two regimens to prevent relapse.

RESULTS

188 patients were studied: 95/188 (51%) men, median age 59 years (range 19-89), prior disease duration 5.0 years (range 0.4-34.5). 149/188 (79%) had previously received cyclophosphamide and 67/188 (36%) rituximab. 119/188 (63%) of relapses had at least one major disease activity item, and 54/188 (29%) received the higher dose glucocorticoid regimen. 171/188 (90%) patients achieved remission by 4 months. Only six patients (3.2% of the study population) did not achieve disease control at month 4. Four patients died in the induction phase due to pneumonia (2), cerebrovascular accident (1), and active vasculitis (1). 41 severe adverse events occurred in 27 patients, including 13 severe infections.

CONCLUSIONS

This large prospective cohort of patients with relapsing AAV treated with rituximab in conjunction with glucocorticoids demonstrated a high level of efficacy for the reinduction of remission in patients with AAV who have relapsed, with a similar safety profile to previous studies.

Interstital lung disease in ANCA vasculitis

Anti-neutrophil cytoplasmic antibodies (ANCA) vasculitides are immune-mediated disorders that primarily affect small blood vessels of the airway and kidneys. Lung involvement, one of the hallmarks of microscopic polyangiitis and granulomatosis with polyangiitis, is associated with increased mortality and morbidity. In recent years, several retrospective series and case reports have described the association of interstitial lung disease (ILD) and ANCA vasculitis, particularly those positive for ANCA specific for myeloperoxidase. In the majority of these patients pulmonary fibrosis occurs concurrently or predates the diagnosis of ANCA vasculitis. More importantly, these studies have shown that ILD has an adverse impact on the long-term prognosis of ANCA vasculitis. This review focuses on the main clinical and radiologic features of pulmonary fibrosis associated with anti-neutrophil cytoplasmic antibodies. Major histopathology features, prognosis and therapeutic options are summarized.

Glucocorticoids and relapse and infection rates in anti-neutrophil cytoplasmic antibody disease

BACKGROUND AND OBJECTIVES

The optimal course of glucocorticoid therapy in anti-neutrophil cytoplasmic autoantibody (ANCA) disease is unknown. This cohort study evaluates effects of glucocorticoid therapy duration on patient outcomes and adverse events.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study assessed 147 patients diagnosed between January 1, 2000 and January 1, 2009 who were treated with glucocorticoids and cyclophosphamide. Patients with end stage kidney disease at presentation, treatment resistance, or who had died within 6 months were excluded. Patients were divided into three groups: 0, 5, or >5 mg prednisone daily at 6 months after therapy initiation. The latter two groups were combined for assessment of adverse events. Wilcoxon rank sum, Kruskal-Wallis, or Fisher's exact tests were used for between-group comparisons. Time to relapse was evaluated by the Kaplan-Meier method with log-rank test for comparison.

RESULTS

There were no differences between groups in ANCA specificity, serum creatinine, frequency of risk factors for relapse, or length of therapy with immunosuppressants. Length of glucocorticoid therapy had no impact on time to relapse (hazard ratio, 0.69 [95% confidence interval (CI), 0.23-2.02]; 1.01, [95% CI, 0.57-1.81] for the 5-mg and >5-mg groups, respectively), relapse-free survival, end stage kidney disease, or death. Patients receiving glucocorticoids beyond 6 months had significantly higher incidence of infections (0.64 infections per person-year versus 0.39, P<0.0001) and a marginally significant higher frequency of new-onset diabetes mellitus (odds ratio, 2.03; 95% CI, 0.94-4.38).

CONCLUSIONS

Glucocorticoid therapy beyond 6 months is associated with a significantly greater risk of infections but not a significantly decreased risk of relapse.

A pilot study using mycophenolate mofetil in relapsing or resistant ANCA small vessel vasculitis

BACKGROUND

The treatment approaches to antineutrophil cytoplasmic autoantibody (ANCA) small vessel vasculitis expose patients to the risks associated with long-term use of corticosteroids and cytotoxic agents. In an effort to explore approaches to minimize risks, we conducted a pilot efficacy and safety study of mycophenolate mofetil (MMF) in the treatment of subjects with nonlife-threatening recurrent or cyclophosphamide-resistant ANCA-vasculitis.

METHODS

MMF was initiated at 500 mg orally twice daily and gradually increased to a target dose of 1000 mg twice daily for a duration of 24 weeks. Concomitant therapy with corticosteroids was allowed. The Birmingham Vasculitis Activity Score (BVAS) was used to assess disease activity and treatment efficacy. ANCA titres, serum creatinine and adverse events were secondary measures of efficacy and/or toxicity.

RESULTS

Twelve subjects were enrolled in the study. Treatment with MMF led to an improvement in disease activity as measured by the BVAS at 24 weeks (P = 0.0013) and 52 weeks (P = 0.0044) as compared to baseline. The BVAS decreased from an average of 9.1+/-3.5 at baseline (range, 3-17) to an average of 2.8+/-1.9 (range, 1-6) at 24 weeks and to 2.8+/-4.3 (range, 0-13) at 52 weeks. Early and sustained reductions in BVAS occurred in subjects initially classified as disease relapses vs those with treatment resistance. Side effect profile was consistent with the mechanism of action and pharmacokinetic disposition of MMF.

CONCLUSIONS

MMF is a reasonable option in the treatment of non-life-threatening recurrent or resistant vasculitis and may obviate the immediate need for recurrent use of cytotoxic agents.

Rituximab therapy for membranous nephropathy: a systematic review

BACKGROUND AND OBJECTIVES

The treatment of membranous nephropathy (MN) remains controversial. Rituximab, which selectively targets B cells, has emerged as a possible alternative treatment option with limited toxicity.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The available data on rituximab therapy for MN were reviewed using the MEDLINE database (inception to August 1, 2008), Google Scholar, and selected reference lists. English-language studies investigating the use of rituximab in idiopathic and secondary MN, in native and transplanted kidneys, were included. Study design, subject number, clinical characteristics (diagnosis, previous and concomitant treatment courses, baseline proteinuria, baseline renal function), rituximab protocol, follow-up period, achievement of complete or partial remission, changes in proteinuria and renal function, and adverse effects of therapy were extracted.

RESULTS

Twenty-one articles were included for review; all were either case reports or case series without controls. More than half of the published cases (50 of 85) came from one center where rituximab was used as primary immunosuppression for idiopathic MN. The available data suggest that rituximab, dosed either as 375 mg/m(2) once weekly for 4 wk or as 1 g on days 1 and 15, achieves a 15 to 20% rate of complete remission and a 35 to 40% rate of partial remission. The drug was well tolerated with minimal adverse events.

CONCLUSIONS

Although rituximab may prove to be a better treatment option for MN than alkylating agents or calcineurin inhibitors, the current literature only supports using the drug in research protocols. Whether, when, how, and why to use rituximab in MN remains to be determined.