GLASGOW, SCOTLAND – Five-year mortality following the diagnosis of systemic rheumatoid vasculitis hovers around 60%, according to an analysis of 34 cases identified in a British-based patient registry.
Although the annual incidence of SRV has reportedly been decreasing since the 1990s, these data suggest it remains a problem despite the introduction of modern immunosuppressive therapies and the use of earlier and more aggressive treatment for rheumatoid arthritis, Dr. Eleana Ntatsaki, a rheumatology specialist trainee at Norfolk and Norwich (England) University Hospital, said at the annual meeting of the British Society for Rheumatology.
The Norfolk Vasculitis Register (NORVASC) is a prospective patient registry established in 1988 to log cases of vasculitis that occur in the county of Norfolk, England. This is a region particularly well suited to epidemiological study, as it is an isolated geographical area with a stable and well-defined population. This is also one of the reasons the Norfolk Arthritis Register (NOAR) is situated in this part of the country.
Between Jan. 1, 2001, and Dec. 31, 2010, a total of 34 cases were reviewed in detail, with 18 patients (10 men) confirmed as having SRV according to previously published criteria (Am. J. Med. 1984;76:377-84), chart review, and independent physician assessment.
The median age of confirmed cases at diagnosis was 72 years and the average disease duration before SRV diagnosis was nearly 16 years. All patients were rheumatoid factor positive, 13 had documented erosive disease, and three had rheumatoid nodules.
All patients had been treated with steroids, a median of two prior DMARDs had been used (methotrexate in 65% of patients), and two patients had received biologic agents. SRV had been treated with intravenous cyclophosphamide (median six cycles) in all but one patient.
The average annual incidence of SRV was calculated to be 3.9 per million (95% confidence interval [CI], 2.3-6.2). This was substantially lower than the 9.1 per million (95% CI, 6.8-12.0) seen in a reference population of 47 patients who developed the complication between 1998 and 2000.
The average annual incidence rates in 2001-2010 were 4.5 (95% CI, 2.2-8.3) for men and 3.4 (95% CI, 1.4-6.6) for women. In 1998-2000, the rates were 8.9 (95% CI, 5.7-13.1) for men and 8.7 (95% CI, 5.6-12.8) for women.
No statistically significant differences were found in the number of patients experiencing systemic, cutaneous, neurologic, pulmonary, renal, ophthalmic, or gastrointestinal manifestations between the two time periods.
Mortality rates at 1 year were also similar between the cohorts, at 12% for 2001-2010 and 14% for 1998-2000. Five-year mortality rates were 60% and 51%, respectively.
"Modern immunosuppression therapy seems to be associated with a decrease in the incidence" of systemic rheumatoid vasculitis, said Dr. Ntatsaki, "but has had no significant influence on clinical features, or outcome."
Whether the decrease in incidence can truly be attributed to methotrexate or improvements in RA treatment in general is questionable, suggested Dr. Deborah Symmons, professor of rheumatology and musculoskeletal epidemiology at the University of Manchester (England).
This decline in the incidence of rheumatoid vasculitis is not necessarily because rheumatoid arthritis treatments have improved, she said. "Perhaps it is just the natural history of rheumatoid arthritis that vasculitis is becoming rare. Clearly when people do get it they do just as badly as they ever did, and perhaps all this about methotrexate is completely coincidental."
Dr. Ntatsaki reported having no financial disclosures.