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Beat A. Michel

Other affiliations: University of Zurich
Bio: Beat A. Michel is an academic researcher from American College of Rheumatology. The author has contributed to research in topics: Vasculitis & Arteritis. The author has an hindex of 10, co-authored 10 publications receiving 10158 citations. Previous affiliations of Beat A. Michel include University of Zurich.

Papers
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Journal ArticleDOI
TL;DR: Criteria for the classification of giant cell (temporal) arteritis were developed by comparing 214 patients who had this disease with 593 patients with other forms of vasculitis, and 2 other variables were included: scalp tenderness and claudication of the jaw or tongue or on deglutition.
Abstract: Criteria for the classification of giant cell (temporal) arteritis were developed by comparing 214 patients who had this disease with 593 patients with other forms of vasculitis. For the traditional format classification, 5 criteria were selected: age greater than or equal to 50 years at disease onset, new onset of localized headache, temporal artery tenderness or decreased temporal artery pulse, elevated erythrocyte sedimentation rate (Westergren) greater than or equal to 50 mm/hour, and biopsy sample including an artery, showing necrotizing arteritis, characterized by a predominance of mononuclear cell infiltrates or a granulomatous process with multinucleated giant cells. The presence of 3 or more of these 5 criteria was associated with a sensitivity of 93.5% and a specificity of 91.2%. A classification tree was also constructed using 6 criteria. These criteria were the same as for the traditional format, except that elevated erythrocyte sedimentation rate was excluded, and 2 other variables were included: scalp tenderness and claudication of the jaw or tongue or on deglutition. The classification tree was associated with a sensitivity of 95.3% and specificity of 90.7%.

2,204 citations

Journal ArticleDOI
TL;DR: Criteria for the classification of Churg-Strauss syndrome were developed by comparing 20 patients who had this diagnosis with 787 control patients with other forms of vasculitis, and advantages of the traditional format compared with the classification tree format are discussed.
Abstract: Criteria for the classification of Churg-Strauss syndrome (CSS) were developed by comparing 20 patients who had this diagnosis with 787 control patients with other forms of vasculitis. For the traditional format classification, 6 criteria were selected: asthma, eosinophilia greater than 10% on differential white blood cell count, mononeuropathy (including multiplex) or polyneuropathy, non-fixed pulmonary infiltrates on roentgenography, paranasal sinus abnormality, and biopsy containing a blood vessel with extravascular eosinophils. The presence of 4 or more of these 6 criteria yielded a sensitivity of 85% and a specificity of 99.7%. A classification tree was also constructed with 3 selected criteria: asthma, eosinophilia greater than 10% on differential white blood cell count, and history of documented allergy other than asthma or drug sensitivity. If a subject has eosinophilia and a documented history of either asthma or allergy, then that subject is classified as having CSS. For the tree classification, the sensitivity was 95% and the specificity was 99.2%. Advantages of the traditional format compared with the classification tree format, when applied to patients with systemic vasculitis, and their comparison with earlier work on CSS are discussed.

1,954 citations

Journal ArticleDOI
TL;DR: Criteria for the classification of Takayasu arteritis were developed by comparing 63 patients who had this disease with 744 control patients with other forms of vasculitis, and the presence of 3 or more of these 6 criteria demonstrated a sensitivity of 90.5% and a specificity of 97.0%.
Abstract: Criteria for the classification of Takayasu arteritis were developed by comparing 63 patients who had this disease with 744 control patients with other forms of vasculitis. Six criteria were selected for the traditional format classification: onset at age less than or equal to 40 years, claudication of an extremity, decreased brachial artery pulse, greater than 10 mm Hg difference in systolic blood pressure between arms, a bruit over the subclavian arteries or the aorta, and arteriographic evidence of narrowing or occlusion of the entire aorta, its primary branches, or large arteries in the proximal upper or lower extremities. The presence of 3 or more of these 6 criteria demonstrated a sensitivity of 90.5% and a specificity of 97.8%. A classification tree also was constructed with 5 of these 6 criteria, omitting claudication of an extremity. The classification tree demonstrated a sensitivity of 92.1% and a specificity of 97.0%.

1,888 citations

Journal ArticleDOI
TL;DR: Criteria for the classification of Wegener's granulomatosis were developed by comparing 85 patients who had this disease with 722 control patients with other forms of vasculitis with a high level of sensitivity and specificity.
Abstract: Criteria for the classification of Wegener's granulomatosis (WG) were developed by comparing 85 patients who had this disease with 722 control patients with other forms of vasculitis. For the traditional format classification, 4 criteria were selected: abnormal urinary sediment (red cell casts or greater than 5 red blood cells per high power field), abnormal findings on chest radiograph (nodules, cavities, or fixed infiltrates), oral ulcers or nasal discharge, and granulomatous inflammation on biopsy. The presence of 2 or more of these 4 criteria was associated with a sensitivity of 88.2% and a specificity of 92.0%. A classification tree was also constructed with 5 criteria being selected. These criteria were the same as for the traditional format, but included hemoptysis. The classification tree was associated with a sensitivity of 87.1% and a specificity of 93.6%. We describe criteria which distinguish patients with WG from patients with other forms of vasculitis with a high level of sensitivity and specificity. This distinction is important because WG requires cyclophosphamide therapy, whereas many other forms of vasculitis can be treated with corticosteroids alone.

1,786 citations

Journal ArticleDOI
TL;DR: Criteria for the classification of polyarteritis nodosa were developed by comparing 118 patients who had this disease with 689 control Patients who had other forms of vasculitis.
Abstract: Criteria for the classification of polyarteritis nodosa were developed by comparing 118 patients who had this disease with 689 control patients who had other forms of vasculitis. For the traditional format classification, 10 criteria were selected: weight loss greater than or equal to 4 kg, livedo reticularis, testicular pain or tenderness, myalgias, mononeuropathy or polyneuropathy, diastolic blood pressure greater than 90 mm Hg, elevated blood urea nitrogen or serum creatinine levels, presence of hepatitis B reactants in serum, arteriographic abnormality, and presence of granulocyte or mixed leukocyte infiltrate in an arterial wall on biopsy. The presence of 3 or more of these 10 criteria was associated with a sensitivity of 82.2% and specificity of 86.6%. A classification tree was also constructed, with 6 criteria being selected. Three of these, angiographic abnormality, biopsy-proven granulocyte or mixed leukocyte infiltrate in arterial wall, and neuropathy, were criteria used in the traditional format. The other 3 criteria used in the tree format included the patient's sex, weight loss greater than 6.5 kg, and elevated serum aspartate aminotransferase or alanine aminotransferase levels above the range of normal. The classification tree yielded a sensitivity of 87.3% and a specificity of 89.3%.

947 citations


Cited by
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Journal ArticleDOI
TL;DR: This report provides the best available prevalence estimates for the US for osteoarthritis, polymyalgia rheumatica, gout, fibromyalgia, and carpal tunnel syndrome as well as the symptoms of neck and back pain.
Abstract: Objective To provide a single source for the best available estimates of the US prevalence of and number of individuals affected by osteoarthritis, polymyalgia rheumatica and giant cell arteritis, gout, fibromyalgia, and carpal tunnel syndrome, as well as the symptoms of neck and back pain. A companion article (part I) addresses additional conditions.

4,813 citations

22 Jan 2008
TL;DR: In this paper, the best available estimates of the US prevalence of and number of individuals affected by osteoarthritis, polymyalgia rheumatica and giant cell arteritis, gout, fibromyalgia, and carpal tunnel syndrome, as well as the symptoms of neck and back pain are provided.
Abstract: OBJECTIVE To provide a single source for the best available estimates of the US prevalence of and number of individuals affected by osteoarthritis, polymyalgia rheumatica and giant cell arteritis, gout, fibromyalgia, and carpal tunnel syndrome, as well as the symptoms of neck and back pain. A companion article (part I) addresses additional conditions. METHODS The National Arthritis Data Workgroup reviewed published analyses from available national surveys, such as the National Health and Nutrition Examination Survey and the National Health Interview Survey. Because data based on national population samples are unavailable for most specific rheumatic conditions, we derived estimates from published studies of smaller, defined populations. For specific conditions, the best available prevalence estimates were applied to the corresponding 2005 US population estimates from the Census Bureau, to estimate the number affected with each condition. RESULTS We estimated that among US adults, nearly 27 million have clinical osteoarthritis (up from the estimate of 21 million for 1995), 711,000 have polymyalgia rheumatica, 228,000 have giant cell arteritis, up to 3.0 million have had self-reported gout in the past year (up from the estimate of 2.1 million for 1995), 5.0 million have fibromyalgia, 4-10 million have carpal tunnel syndrome, 59 million have had low back pain in the past 3 months, and 30.1 million have had neck pain in the past 3 months. CONCLUSION Estimates for many specific rheumatic conditions rely on a few, small studies of uncertain generalizability to the US population. This report provides the best available prevalence estimates for the US, but for most specific conditions more studies generalizable to the US or addressing understudied populations are needed.

4,355 citations

Journal ArticleDOI
TL;DR: 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides J. Watts; Arthritis & Rheumatism
Abstract: 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides J. Jennette;R. Falk;P. Bacon;N. Basu;M. Cid;F. Ferrario;L. Flores-Suarez;W. Gross;L. Guillevin;E. Hagen;G. Hoffman;D. Jayne;C. Kallenberg;P. Lamprecht;C. Langford;R. Luqmani;A. Mahr;E. Matteson;P. Merkel;S. Ozen;C. Pusey;N. Rasmussen;A. Rees;D. Scott;U. Specks;J. Stone;K. Takahashi;R. Watts; Arthritis & Rheumatism

4,249 citations

Journal ArticleDOI
TL;DR: The validity of the Swedish IPR is high for many but not all diagnoses, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.
Abstract: Background: The Swedish National Inpatient Register (IPR), also called the Hospital Discharge Register, is a principal source of data for numerous research projects. The IPR is part of the National Patient Register. The Swedish IPR was launched in 1964 (psychiatric diagnoses from 1973) but complete coverage did not begin until 1987. Currently, more than 99% of all somatic (including surgery) and psychiatric hospital discharges are registered in the IPR. A previous validation of the IPR by the National Board of Health and Welfare showed that 85-95% of all diagnoses in the IPR are valid. The current paper describes the history, structure, coverage and quality of the Swedish IPR. Methods and results: In January 2010, we searched the medical databases, Medline and HighWire, using the search algorithm “validat* (inpatient or hospital discharge) Sweden”. We also contacted 218 members of the Swedish Society of Epidemiology and an additional 201 medical researchers to identify papers that had validated the IPR. In total, 132 papers were reviewed. The positive predictive value (PPV) was found to differ between diagnoses in the IPR, but is generally 85-95%. Conclusions: In conclusion, the validity of the Swedish IPR is high for many but not all diagnoses. The long followup makes the register particularly suitable for large-scale population-based research, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.

3,871 citations

Journal ArticleDOI
TL;DR: The following are some of the conclusions and proposals made at the Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitis.
Abstract: The following are some of the conclusions and proposals made at the Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitis. 1. Although not a prerequisite component of the definitions, patient age is recognized as a useful discriminator between Takayasu arteritis and giant cell (temporal) arteritis. 2. The name "polyarteritis nodosa," or alternatively, the name "classic polyarteritis nodosa," is restricted to disease in which there is arteritis in medium-sized and small arteries without involvement of smaller vessels. Therefore, patients with vasculitis affecting arterioles, venules, or capillaries, including glomerular capillaries (i.e., with glomerulonephritis), are excluded from this diagnostic category. 3. The name "Wegener's granulomatosis" is restricted to patients with granulomatous inflammation. Patients with exclusively nongranulomatous small vessel vasculitis involving the upper or lower respiratory tract (e.g., alveolar capillaritis) fall into the category of microscopic polyangiitis (microscopic polyarteritis). 4. The term "hypersensitivity vasculitis" is not used. Most patients who would have been given this diagnosis fall into the category of microscopic polyangiitis (microscopic polyarteritis) or cutaneous leukocytoclastic angiitis. 5. The name "microscopic polyangiitis," or alternatively, "microscopic polyarteritis," connotes pauci-immune (i.e., few or no immune deposits) necrotizing vasculitis affecting small vessels, with or without involvement of medium-sized arteries. Cryoglobulinemic vasculitis, Henoch-Schonlein purpura, and other forms of immune complex-mediated small vessel vasculitis must be ruled out to make this diagnosis. 6. The name "cutaneous leukocytoclastic angiitis" is restricted to vasculitis in the skin without involvement of vessels in any other organ. 7. Mucocutaneous lymph node syndrome must be present to make a diagnosis of Kawasaki disease.(ABSTRACT TRUNCATED AT 250 WORDS)

3,550 citations