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Overall survival and survival free of end-stage renal disease (ESRD) have both improved significantly over time in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), but the risk of relapse has not.
In a large multicenter inception cohort of patients with AAV and renal involvement, the only predictor of better outcome was serum creatinine at diagnosis, "suggesting that early detection is fundamental to improving ESRD-free survival in AAV," noted Rennie L. Rhee, MD, from the University of Pennsylvania, Philadelphia, and colleagues.
Renal involvement is a common complication of AAV and portends a poor prognosis. "Over the past several decades, patients with AAV have survived longer but whether morbidity has improved in terms of preservation of kidney function is unclear," the authors wrote online in Arthritis & Rheumatology.
They studied the impact of diagnostic and therapeutic changes on long-term outcomes in AAV in 554 patients with glomerulonephritis from the Glomerular Disease Collaborative Network AAV registry. The goal of the study was to examine changes in long-term outcomes over the 25-year period of 1985 to 2010.
Participants' median age was 60 years and 47% were female.
Renal function at diagnosis significantly improved over time, with a median estimated glomerular filtration rate (eGFR) of 11 mL/min/1.73 m2in the first 5 years of the registry and 23 mL/min/1.73 m2in the most recent 5-year period.
The study "showed consistent results indicating that better renal function at diagnosis is associated with improved survival and renal outcomes," wrote Rhee and colleagues.
Two hundred sixty (47%) patients developed ESRD and/or died during follow-up, and the rate of the occurrence of ESRD or death was 12.9 events per 100 patient-years. The ESRD-free survival rate at 1 year was 75% and the 5-year rate was 54%. The 5-year risk of ESRD or death decreased over time (log rank test for trendP<0.001).
Among patients with severe renal disease, defined as eGFR of 45 mL/min/1.73 m2or less, there also was a significant improvement in ESRD-free survival over time (log rank test for trendP< 0.001).
In a subgroup multivariable analysis of patients who received cyclophosphamide, an elevated baseline serum creatinine was the only factor associated with an increased risk of ESRD or death, with a hazard ratio of 1.11 per 1 mg/dL of serum creatinine (95% CI 1.04-1.18,P=0.002).
Among the overall cohort, 160 deaths occurred, corresponding to an incidence rate of seven deaths per 100 patient-years. One-year survival was 91% and 5-year survival was 72%. Survival significantly improved over time, even after adjustments for factors such as baseline serum creatinine and treatment with cyclophosphamide (P=0.03).
One hundred eighty-one (33%) patients developed ESRD over the course of the study. By 1 and 5 years, 20% and 65% of patients respectively had developed ESRD, and at those time points 5% and 23% had died of causes other than ESRD. After adjustments, renal survival significantly improved across the time of the study (P=0.03).
The relapse rate was 13.9 events per 100 patient-years. The cumulative occurrence of relapse was 11% at 1 year, 29% at 3 years, and 35% at 5 years. Among the 185 patients with a relapse, 74% had evidence of renal involvement and 61% were given cyclophosphamide to treat the relapse.
The unadjusted occurrence of relapse increased over time (P<0.001), a trend that was no longer significant in the 340 patients with data on cyclophosphamide use after adjusting for potential confounders (P=0.45).
One-fourth of patients experienced a renal relapse, and there was no significant difference in the occurrence of renal relapses over time. Unlike a prior study, ANCA type was not associated with occurrence of relapse, which may have been "due to the enrichment of the cohort with patients with renal disease ... and censoring all patients after 5 years of follow-up," according to the authors.
There was also no association found between duration of cyclophosphamide use and relapse.
Unmeasured confounders, such as the dose and duration of use of glucocorticoids and other immunosuppressive therapies, represent a potential limitation to the study. Also, 32% of patients were lost to follow-up by 5 years from diagnosis, which may have affected results, and improvements in healthcare over time may have influenced long-term outcomes.
The study was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH. Rhee has been supported by the Rheumatology Research Foundation and the Vasculitis Foundation. One other author disclosed financial relationships with Actelion, Alexion, ChemoCentryx, Sanofi, Bristol-Myers Squibb, Celgene, ChemoCentryx, Genentech/Roche and GlaxoSmithKline. Rhee receives support from the Rheumatology Research Foundation and Vasculitis Foundation.
This article is brought to RheumNow by our friends at MedPage Today. It was originally published February 8, 2016.