Long-term outcome of kidney function in patients with ANCA-associated vasculitis

BACKGROUND

Kidney involvement is common in ANCA associated vasculitis (AAV) and prognosis determined by the severity of kidney damage. This study focused on long-term kidney outcomes, defining possible risk factors and comparing the performance of three different histological classifications to predict outcomes for patients with AAV.

METHODS

The dataset included 848 patients with newly diagnosed AAV who participated in 7 RCTs (1995-2012). Follow up information obtained from questionnaires sent to the principal investigators of the original RCTs.

RESULTS

The cumulative incidence of end-stage kidney disease (ESKD) at 5 and 10 years was 17% and 22%, respectively. Patients who developed ESKD had reduced patient survival compared to those with preserved kidney function (HR: 2.8, P-value < 0.001). Comparing patients with AAV and kidney involvement to a matched general population, patients with AAV had poor survival outcomes, even in early stages of CKD. The main cause of death was infection followed by cardiovascular disease in patients developing ESKD and malignancy in those who did not. 34% of patients with initial need for dialysis recovered kidney function after treatment. 35 out of 175 in need of kidney replacement therapy (KRT) during follow up received a kidney transplant with good outcome; 86% patient survival at 10 years.In the subcohort of 214 patients with available kidney biopsies, three scoring systems were tested: the Berden classification, the Renal Risk Score (RRS), and the Mayo Clinic Score (MCCS). The scores highlighted the importance of normal glomeruli and severe glomerulosclerosis on kidney survival (P < 0.001 and P = 0.001, respectively). The RRS demonstrated a moderate prediction of kidney survival (AUC: 0.79; SE: 0.03, 95% CI: 0.71-0.83).

CONCLUSIONS

Early diagnosis is extremely important. Even milder forms of kidney involvement have an impact on the prognosis. Patients in need of KRT had the lowest survival rates, but kidney transplantation has shown favorable outcomes for eligible AAV patients. The three histologic scoring systems were all identified as independent prognostic factors for kidney outcome.

PROTEINURIA AND HEMATURIA AFTER REMISSION INDUCTION ARE ASSOCIATED WITH OUTCOME IN ANCA-ASSOCIATED VASCULITIS

In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), hematuria and proteinuria are biomarkers reflecting kidney involvement at diagnosis. Yet, the prognostic value of their persistence after immunosuppressive induction therapy, reflecting kidney damage or persistent disease, remains uncertain. To study this, our post-hoc analysis included participants of five European randomized clinical trials on AAV (MAINRITSAN, MAINRITSAN2, RITUXVAS, MYCYC, IMPROVE). Urine protein-creatinine ratio (UPCR) and hematuria of spot urine samples collected at the end of induction therapy (four-six months after treatment initiation) were correlated with the occurrence of a combined endpoint of death and/or kidney failure, or relapses during follow-up. Among 571 patients (59% men, median age 60), 60% had anti-proteinase 3-ANCA and 35% had anti-myeloperoxidase-ANCA, while 77% had kidney involvement. After induction therapy, 157/526 (29.8%) had persistent hematuria and 165/481 (34.3%) had UPCR of 0.05 g/mmol or more. After a median follow-up of 28 months (inter quartile range 18-42), and adjustment for age, ANCA type, maintenance therapy, serum creatinine and persistent hematuria after induction, a UPCR of 0.05 g/mmol or more after induction was associated with significant risk of death/kidney failure (adjusted Hazard Ratio (HR) 3.06, 95% confidence interval (1.09-8.59) and kidney relapse (adjusted subdistribution HR 2.22, 1.16-4.24). Persistent hematuria was associated with significant kidney relapse (adjusted subdistribution HR 2.16, (1.13-4.11) but not with relapse affecting any organ nor with death/kidney failure. Thus, in this large cohort of patients with AAV, persistent proteinuria after induction therapy was associated with death/kidney failure and kidney relapse, whereas persistent hematuria was an independent predictor of kidney relapse. Hence, these parameters must be considered to assess long-term kidney prognosis of patients with AAV.

Negative anti-neutrophil cytoplasm antibody at switch to maintenance therapy is associated with a reduced risk of relapse

BACKGROUND

Relapse of disease is frequent in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). It is unclear whether persistent ANCA when starting maintenance therapy increases the risk of relapse. We examined the association between ANCA status and relapse in two randomised controlled trials.

METHODS

ANCA-positive patients in two trials, CYCLOPS and IMPROVE, were switched from cyclophosphamide to maintenance therapy after achieving clinical remission. We classified patients as being either ANCA-positive or ANCA-negative at the time they started maintenance therapy. We compared the risk of relapse in ANCA-positive and ANCA-negative patients.

RESULTS

Of 252 patients included, 102 (40%) experienced at least one relapse during the follow-up period. At the time of the switch from induction to maintenance therapy, 111 were ANCA-positive, of whom 55 (50%) relapsed, compared to 141 patients who were ANCA-negative, of whom 47 (33%) relapsed. In multivariable time-to-event analysis, a reduced risk of relapse was associated with having become ANCA-negative at the time of switching to maintenance therapy (hazard ratio 0.63, 95% confidence interval 0.42-0.95; p = 0.026). In addition, initial proteinase 3 (PR3)-ANCA, younger age, lower serum creatinine, pulsed cyclophosphamide for remission induction, and mycophenolate mofetil for remission maintenance were all associated with an increased risk of relapse.

CONCLUSIONS

Becoming ANCA-negative before the switch to maintenance is associated with a reduced risk of relapse.

TRIAL REGISTRATION

CYCLOPS: ClinicalTrials.gov, NCT00430105 . Registered retrospectively on 31 January 2007.

IMPROVE

ClinicalTrials.gov, NCT00307645 . Registered retrospectively on 27 March 2006.

Long-term follow-up of cyclophosphamide compared with azathioprine for initial maintenance therapy in ANCA-associated vasculitis

BACKGROUND AND OBJECTIVES

Treatment with azathioprine within 3 months of remission induction with cyclophosphamide is a common treatment strategy for patients with ANCA-associated vasculitis. This study comprised patients undergoing long-term follow-up who were randomly allocated to azathioprine after 3-6 months or after 12 months of cyclophosphamide treatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients from 39 European centers between 1995 and 1997 with a new diagnosis of ANCA-associated vasculitis that involved the kidneys or another vital organ were eligible. At the time of diagnosis, participants were randomly allocated to convert to azathioprine after 3-6 months (the azathioprine group) or after 12 months of cyclophosphamide (the cyclophosphamide group). Patients who did not achieve a remission within 6 months were excluded. This study assessed relapses, ESRD, and death during long-term follow-up.

RESULTS

Patients were allocated to the azathioprine group (n=71) and the cyclophosphamide group (n=73). Of these patients, 63 (43.8%) developed a relapse, 35 (24.3%) developed a renal relapse, 13 (9.0%) developed ESRD, and 21 (14.6%) died. Although there were worse outcomes in the azathioprine group, none were statistically significant. The subdistribution hazard ratio [sHR] for relapse was 1.63 (95% confidence interval [95% CI], 0.99 to 2.71), the composite of relapse or death hazard ratio [HR] was 1.59 (95% CI, 1.00 to 2.54), the ESRD sHR was 1.71 (95% CI, 0.56 to 5.19), and the death HR was 0.75 (95% CI, 0.32 to 1.79).

CONCLUSIONS

It remains uncertain whether converting to azathioprine after 3-6 months of induction cyclophosphamide therapy is as effective as converting after 12 months. Outcomes are still poor for this group of patients and further research is required to determine the optimal timing of maintenance therapy.

Risk factors for relapse of antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

To determine the association between characteristics at diagnosis and the time to first relapse in a large cohort of patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

We studied long-term followup data from 4 clinical trials that included newly diagnosed patients with a broad spectrum of AAV severity and manifestations. Patient and disease characteristics at baseline were used in competing risk regression models with relapse as the event of interest and death as the competing event.

RESULTS

We assessed 535 patients with 1,804 patient-years at risk of relapse. At diagnosis, the median age was 60.7 years (interquartile range [IQR] 48.8-69.1 years), 284 patients (53%) had granulomatosis with polyangiitis (Wegener's), and the median creatinine level was 203 μmoles/liter (IQR 97-498). A total of 201 patients (38%) experienced a relapse and 133 patients (25%) died, 96 of whom had not had prior relapse. Anti-proteinase 3 antibodies (subhazard ratio [sHR] 1.62 [95% confidence interval 1.39-1.89]) and cardiovascular involvement (sHR 1.59 [95% confidence interval 1.07-2.37]) were independently associated with a higher risk of relapse. Compared with patients with a creatinine level ≤100 μmoles/liter, patients with higher creatinine levels had a lower risk of relapse (sHR 0.81 [95% confidence interval 0.77-0.85] for a creatinine level of 101-200 μmoles/liter; sHR 0.39 [95% confidence interval 0.22-0.69] for a creatinine level >200 μmoles/liter).

CONCLUSION

Relapse of disease is common for patients with AAV. A creatinine level >200 μmoles/liter at the time of diagnosis is strongly associated with a reduced risk of relapse and may help guide monitoring and treatment of patients with AAV.

Long-term patient survival in ANCA-associated vasculitis

BACKGROUND

Wegener's granulomatosis and microscopic polyangiitis are antineutrophil cytoplasm antibodies (ANCA)-associated vasculitides with significant morbidity and mortality. The long-term survival of patients with ANCA associated vasculitis treated with current regimens is uncertain.

OBJECTIVE

To describe the long-term patient survival and possible prognostic factors at presentation in an international, multicentre, prospectively recruited representative patient cohort who were treated according to strictly defined protocols at presentation and included the full spectrum of ANCA-associated vasculitis disease.

METHODS

Outcome data were collected for 535 patients who had been recruited at the time of diagnosis to four randomised controlled trials between 1995 and 2002. Trial eligibility was defined by disease severity and extent, covered the spectrum of severity of ANCA-associated vasculitis and used consistent diagnostic criteria. Demographic, clinical and laboratory parameters at trial entry were tested as potential prognostic factors in multivariable models.

RESULTS

The median duration of follow-up was 5.2 years and 133 (25%) deaths were recorded. Compared with an age- and sex-matched general population there was a mortality ratio of 2.6 (95% CI 2.2 to 3.1). Main causes of death within the first year were infection (48%) and active vasculitis (19%). After the first year the major causes of death were cardiovascular disease (26%), malignancy (22%) and infection (20%). Multivariable analysis showed an estimated glomerular filtration rate <15 ml/min, advancing age, higher Birmingham Vasculitis Activity Score, lower haemoglobin and higher white cell count were significant negative prognostic factors for patient survival.

CONCLUSION

Patients with ANCA-associated vasculitis treated with conventional regimens are at increased risk of death compared with an age- and sex-matched population.

Real time monitoring of laser-induced thermal changes in cartilage in vitro by using snapshot FLASH

Snapshot FLASH imaging has been applied to study the spatial and temporal spreading of thermal changes caused by a Holmium:YAG laser in patella cartilage in vitro at 7 T. The temperature dependence of the proton resonance frequency was used to demonstrate the thermal energy deposition. A series of cartilage images, with a time resolution of 512 ms and a spatial resolution of 400 x 200 microm, showed dynamic changes of the temperature-related image phase in the regions irradiated by the laser.

[Magnetic resonance imaging and temperature measurement in cartilage following laser therapy]

The aim of this study was the dynamic measurement, with magnetic resonance imaging, of temperature in cartilage irradiated by laser. Fresh specimens, each with chondromalacia grade II and III, were irradiated with a Holmium:YAG laser under MRI control. Temperature was measured by means of the proton-shift method, which allows high temporal and spatial resolution. With this method a maximum increase in temperature of 35 degrees was found after irradiation with 1.0 J and 10 Hz for 5 s at a distance of 1 mm. In no case at all was an increase in temperature of more than 10 degrees observed in the cartilage adjacent to the subchondral bone. These results exclude the possibility of significant thermal damage from laser treatment as described.