Vasculitis
Abstract 1266: Polyarteritis nodosa (PAN): Clinical description and long-term outcome of the 351 patients from the French Vasculitis Study Group
Authors: Christian Pagnoux, Raphaele Seror, Alfred Mahr, Pascal Cohen, Luc Mouthon, Loic Guillevin, for the French Vasculitis Study Group
Background: Polyarteritis nodosa is the archetype of vasculitis. Since its initial description, however, it became clear that polyarteritis nodosa existed in two forms—the first, “classical” form of polyarteritis nodosa was a medium-vessel vasculitis; a second form had features of both medium and small vessel vasculitis. In 1994, the Chapel Hill Consensus Conference recognized that these phenotypes represented 2 distinct diseases, and the latter form was renamed microscopic polyangiitis. We now know that classical polyarteritis nodosa is frequently associated with hepatitis B infection, whereas microscopic polyangiitis is associated with antinuclear cytoplasmic autoantibodies, and can lead to a pulmonary-renal hemorrhage syndrome similar to that associated with Wegener’s granulomatosis and Goodpasture’s disease. Much of our understanding of polyarteritis nodosa comes from the French Vasculitis Study Group, but because their seminal work in this field predates the Chapel Hill reclassification, it has been difficult to interpret in modern terms. This abstract reports the results of a reanalysis of the French Vasculitis Study Group patient database using modern definitions.
Study Design: The French Vasculitis Study Group has systematically recorded data submitted by participating physicians since 1981. This database was reviewed, and 351 patients with the classical form of polyarteritis nodosa were identified. Patients who had features of both polyarteritis nodosa and microscopic polyangiitis were excluded from this study.
Results: Of the 351 cases identified, 35% were associated with hepatitis B infection. At the time of diagnosis, over half of patients had constitutional symptoms, peripheral neuropathy, and renovascular involvement. Microaneurysms were most frequently found in the kidney (64.3%) and mesenteric arteries (57.7%). C-reactive protein at time of diagnosis was 101.7 +/- 95 mg/dL. Hepatitis B-associated polyarteritis nodosa was less likely to have cutaneous manifestations (37% versus 57.5%), but more likely to have cardiac involvement (13% versus 4.8%), peripheral neuropathy (85.4% versus 67.5%), and gastrointestinal manifestations (50.4% versus 31.1%). Hepatitis B-associated polyarteritis nodosa was also less prone to relapse (32.5% versus 12.2%), but was associated with higher mortality (34.1% versus 19.3%). In multivariate analysis, gastrointestinal involvement, age greater than 65 years, and hypertension were all associated with poor outcomes.
Editorial Comments: The obvious criticisms apply to this sort of work—the database was analyzed retrospectively using criteria that were not developed until over a decade after its inception. Also, the data were collected by a large coalition of investigators from all over France, giving rise to questions regarding the quality of the initial data collection. That said, the authors argue convincingly that with the declining prevalence of hepatitis B infections, studies of polyarteritis nodosa will only become more difficult in the future. Curiously, patients with hepatitis B-associated polyarteritis nodosa have a higher mortality, but a lower relapse rate. It will be interesting to see how the era of antiviral therapeutics impacts this observation.