1135
THE AMERICAN COLLEGE OF RHEUMATOLOGY 1990 CRITERIA FOR THE CLASSIFICATION OF VASCULITIS Summary JAMES F. FRIES,GENE G. HUNDER, DANIEL A. BLOCH, BEAT A. MICHEL, WILLIAM P. AREND, LEONARD H. CALABRESE, ANTHONY S. FAUCI, RAND1 Y. LEAVITT, J. T. LIE, ROBERT W. LIGHTFOOT, JR., ALFONSE T. MASI, DENNIS J. McSHANE, JOHN A. MILLS, MARY BETTY STEVENS, STANLEY L. WALLACE, and NATHAN J. ZVAIFLER The studies described in the preceding pages regarding the classification of vasculitis are some of the first to be performed through the analysis of patient data collected in a prospective manner. The aim of this project was to develop classification criteria that would promote the more uniform description of the patients when various research endeavors are reported. The large number of patients that were included (n = 1,000) and the inclusion of data from multiple centers (n = 47) are major strengths of these studies, helping to reduce referral bias by individual physicians and centers. The information on the patient data forms was reviewed carefully by the subcommittee members From the American College of Rheumatology Subcommittee on Classification of Vasculitis (Diagnostic and Therapeutic Criteria Committee of the Council on Research). James F. Fries, MD: Stanford University, Stanford, CA; Gene G. Hunder, MD: Mayo Clinic, Rochester, MN, and Chair, Subcommittee on Classification of Vasculitis; Daniel A. Bloch. PhD Stanford University, Stanford, CA; Beat A. Michel. MD. Rheumaklinik Universitiitsspital. Zurich, Switzerland; William P. Arend, MD: University of Colorado Health Science Center, Denver, CO; Leonard H. Calabrese, DO: Cleveland Clinic Foundation, Cleveland, OH; Anthony S. Fauci. MD: NIAID. NIH, Bethesda, MD; Randi Y. Leavitt, MD, PhD: NIAID, NIH, Bethesda, MD; J. T. Lie, MD: Mayo Clinic, Rochester, MN; Robert W. Lightfoot, Jr., MD: University of Kentucky, Lexington, KY; Alfonse T. Masi, MD, DrPH: University of Illinois College of Medicine, Peoria, 1L; Dennis J. McShane, MD: Stanford University, Stanford. CA; John A. Mills, M D Massachusetts General Hospital, Boston, MA: Mary Betty Stevens. MD: Johns Hopkins University, Baltimore, MD; Stanley L.Wallace. MD: SUNY Downstate Medical Center, Brooklyn, NY (Dr. Wallace is deceased); Nathan J. Zvaifler, MD: University of California, San Diego, San Diego, CA. Address reprint requests to the American College of Rheumatology, 17 Executive Park Drive NE, Suite 480, Atlanta, GA 30329.
Submitted for publication October 2 , 1989; accepted in revised form April 3, 1990. Arthritis and Rheumatism, Vol. 33, No. 8 (August 1990)
before and after the data were coded and entered into the computer; these steps also enhanced the accuracy. Statistical analyses utilized ARAMIS (Arthritis, Rheumatism, and Aging Medical Information System) procedures and staff experienced in prior efforts of criteria development. Flexibility was provided by the development of criteria by 2 different methods: the traditional format and the classification tree. The criteria in both formats are presented in relatively simple terms and should prove easy to use. The clinical information needed to fulfill the criteria variables can be obtained from the patient’s medical history, the physical examination, and established laboratory tests that can be performed in most centers. Data regarding less common tests were not reported on the forms in all instances; however, we examined trends and found that such factors as immune complexes, reduced complement levels, or other immunologic data did not indicate that these might have been important discriminators had the information been available for all patients. Yet, further studies may show that other tests are important. One such possibility, the test for antineutrophil cytoplasmic antibodies, which was recently reported in Wegener’s granulomatosis, was described only after data had been collected from many patients (Abbott F, Jones S, Lockwood CM,Rees AJ: Autoantibodies to glomerular antigens in patients with Wegener’s granulomatosis. Nephrol Dial Transplant 4: 1-8, 1989). Biopsy verified the presence of vasculitis in the majority of cases. It appeared that patients with negative biopsies or those who had not undergone biopsy were not different from those whose biopsy findings were positive. Many patients can be classified without
FRIES ET AL
1136 Table 1. Summary of the sensitivity and specificity of the American College of Rheumatology 1990 classification of vasculitis Vasculitis type Polyarteritis nodosa Churg-Strauss syndrome Wegener’s granulornatosis Hypersensitivity vasculitis Henoch-Schdnlein PUrPUra Giant cell (temporal) arteritis Takayasu arteritis
Classification method
Sensitivity
Specificity
(%I
(%)
Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree
82.2 87.3 85.0 95.0 88.2 87.1 71.0 78.5 87.1 89.4 93.5 95.3 90.5 92.1
86.6 89.3 99.7 99.2 92.0 93.6 83.9 78.7 87.7 88.1 91.2 90.7 97.8 97.0
biopsy data. From a clinical standpoint, however, a biopsy should be obtained when possible. Several limitations also should be noted. The studies were not global in the sense that criteria were established for only the most common types of vasculitis. Criteria for each type of vasculitis were developed by comparing findings in patients with that type of vasculitis with findings in the remaining group of patients with other forms of vasculitis; this served the general question of differential diagnosis. Comparisons of the criteria sets between individual types of vasculitis were not extensive. The sensitivity and specificity rates for the vasculitides studied varied considerably, from approximately 70% to more than 99% (Table 1). In most instances, and when possible, we selected criteria sets that were reasonably balanced between sensitivity and specificity values. Rates of over 90% were found in Churg-Strauss syndrome, giant cell (temporal) arteritis, and Takayasu arteritis. These conditions are fairly
well defined from a clinical standpoint, although they have a broad range of manifestations. Rates below 80% were found for hypersensitivity vasculitis. This syndrome has been difficult to define, and its definition has varied widely from one author to another. A specific formula to guide the investigator toward the proper criteria set to use when classifying a patient was not developed. If the diagnosis is known, that criteria set should, of course, be used. In other instances, the physician needs to make a judgment regarding the patient’s most likely diagnosis, and then, use the appropriate criteria set. When the diagnosis is unknown, it may be useful to examine more than one set of criteria. Experience with using the criteria will provide the best guidance. Either the traditional format or the tree classification can be applied; however, uniformity should be maintained throughout a given study. These criteria sets may be used to describe the patients included in studies of vasculitis. Their use should enhance uniformity of reporting. A brief perusal of the literature reveals that a wide variety of descriptions (or lack of descriptions) of patients have been used in reporting these conditions. As new information becomes available about these syndromes and their specific causes, it is expected that it may become necessary to revise these sets of classification criteria. Despite these caveats, which are unavoidable given current knowledge of these syndromes and their largely descriptive nature, experience with classification criteria in other areas of rheumatic disease has shown that criteria can be extremely useful. They help standardize our clinical vocabularies, aid in estimating prognosis, encourage more systematic definition of study patients, and provide a conceptual base against which to assess the merits of new information.
THE AMERICAN COLLEGE OF RHEUMATOLOGY 1990 CRITERIA FOR THE CLASSIFICATION OF VASCULITIS Summary JAMES F. FRIES,GENE G. HUNDER, DANIEL A. BLOCH, BEAT A. MICHEL, WILLIAM P. AREND, LEONARD H. CALABRESE, ANTHONY S. FAUCI, RAND1 Y. LEAVITT, J. T. LIE, ROBERT W. LIGHTFOOT, JR., ALFONSE T. MASI, DENNIS J. McSHANE, JOHN A. MILLS, MARY BETTY STEVENS, STANLEY L. WALLACE, and NATHAN J. ZVAIFLER The studies described in the preceding pages regarding the classification of vasculitis are some of the first to be performed through the analysis of patient data collected in a prospective manner. The aim of this project was to develop classification criteria that would promote the more uniform description of the patients when various research endeavors are reported. The large number of patients that were included (n = 1,000) and the inclusion of data from multiple centers (n = 47) are major strengths of these studies, helping to reduce referral bias by individual physicians and centers. The information on the patient data forms was reviewed carefully by the subcommittee members From the American College of Rheumatology Subcommittee on Classification of Vasculitis (Diagnostic and Therapeutic Criteria Committee of the Council on Research). James F. Fries, MD: Stanford University, Stanford, CA; Gene G. Hunder, MD: Mayo Clinic, Rochester, MN, and Chair, Subcommittee on Classification of Vasculitis; Daniel A. Bloch. PhD Stanford University, Stanford, CA; Beat A. Michel. MD. Rheumaklinik Universitiitsspital. Zurich, Switzerland; William P. Arend, MD: University of Colorado Health Science Center, Denver, CO; Leonard H. Calabrese, DO: Cleveland Clinic Foundation, Cleveland, OH; Anthony S. Fauci. MD: NIAID. NIH, Bethesda, MD; Randi Y. Leavitt, MD, PhD: NIAID, NIH, Bethesda, MD; J. T. Lie, MD: Mayo Clinic, Rochester, MN; Robert W. Lightfoot, Jr., MD: University of Kentucky, Lexington, KY; Alfonse T. Masi, MD, DrPH: University of Illinois College of Medicine, Peoria, 1L; Dennis J. McShane, MD: Stanford University, Stanford. CA; John A. Mills, M D Massachusetts General Hospital, Boston, MA: Mary Betty Stevens. MD: Johns Hopkins University, Baltimore, MD; Stanley L.Wallace. MD: SUNY Downstate Medical Center, Brooklyn, NY (Dr. Wallace is deceased); Nathan J. Zvaifler, MD: University of California, San Diego, San Diego, CA. Address reprint requests to the American College of Rheumatology, 17 Executive Park Drive NE, Suite 480, Atlanta, GA 30329.
Submitted for publication October 2 , 1989; accepted in revised form April 3, 1990. Arthritis and Rheumatism, Vol. 33, No. 8 (August 1990)
before and after the data were coded and entered into the computer; these steps also enhanced the accuracy. Statistical analyses utilized ARAMIS (Arthritis, Rheumatism, and Aging Medical Information System) procedures and staff experienced in prior efforts of criteria development. Flexibility was provided by the development of criteria by 2 different methods: the traditional format and the classification tree. The criteria in both formats are presented in relatively simple terms and should prove easy to use. The clinical information needed to fulfill the criteria variables can be obtained from the patient’s medical history, the physical examination, and established laboratory tests that can be performed in most centers. Data regarding less common tests were not reported on the forms in all instances; however, we examined trends and found that such factors as immune complexes, reduced complement levels, or other immunologic data did not indicate that these might have been important discriminators had the information been available for all patients. Yet, further studies may show that other tests are important. One such possibility, the test for antineutrophil cytoplasmic antibodies, which was recently reported in Wegener’s granulomatosis, was described only after data had been collected from many patients (Abbott F, Jones S, Lockwood CM,Rees AJ: Autoantibodies to glomerular antigens in patients with Wegener’s granulomatosis. Nephrol Dial Transplant 4: 1-8, 1989). Biopsy verified the presence of vasculitis in the majority of cases. It appeared that patients with negative biopsies or those who had not undergone biopsy were not different from those whose biopsy findings were positive. Many patients can be classified without
FRIES ET AL
1136 Table 1. Summary of the sensitivity and specificity of the American College of Rheumatology 1990 classification of vasculitis Vasculitis type Polyarteritis nodosa Churg-Strauss syndrome Wegener’s granulornatosis Hypersensitivity vasculitis Henoch-Schdnlein PUrPUra Giant cell (temporal) arteritis Takayasu arteritis
Classification method
Sensitivity
Specificity
(%I
(%)
Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree Traditional Tree
82.2 87.3 85.0 95.0 88.2 87.1 71.0 78.5 87.1 89.4 93.5 95.3 90.5 92.1
86.6 89.3 99.7 99.2 92.0 93.6 83.9 78.7 87.7 88.1 91.2 90.7 97.8 97.0
biopsy data. From a clinical standpoint, however, a biopsy should be obtained when possible. Several limitations also should be noted. The studies were not global in the sense that criteria were established for only the most common types of vasculitis. Criteria for each type of vasculitis were developed by comparing findings in patients with that type of vasculitis with findings in the remaining group of patients with other forms of vasculitis; this served the general question of differential diagnosis. Comparisons of the criteria sets between individual types of vasculitis were not extensive. The sensitivity and specificity rates for the vasculitides studied varied considerably, from approximately 70% to more than 99% (Table 1). In most instances, and when possible, we selected criteria sets that were reasonably balanced between sensitivity and specificity values. Rates of over 90% were found in Churg-Strauss syndrome, giant cell (temporal) arteritis, and Takayasu arteritis. These conditions are fairly
well defined from a clinical standpoint, although they have a broad range of manifestations. Rates below 80% were found for hypersensitivity vasculitis. This syndrome has been difficult to define, and its definition has varied widely from one author to another. A specific formula to guide the investigator toward the proper criteria set to use when classifying a patient was not developed. If the diagnosis is known, that criteria set should, of course, be used. In other instances, the physician needs to make a judgment regarding the patient’s most likely diagnosis, and then, use the appropriate criteria set. When the diagnosis is unknown, it may be useful to examine more than one set of criteria. Experience with using the criteria will provide the best guidance. Either the traditional format or the tree classification can be applied; however, uniformity should be maintained throughout a given study. These criteria sets may be used to describe the patients included in studies of vasculitis. Their use should enhance uniformity of reporting. A brief perusal of the literature reveals that a wide variety of descriptions (or lack of descriptions) of patients have been used in reporting these conditions. As new information becomes available about these syndromes and their specific causes, it is expected that it may become necessary to revise these sets of classification criteria. Despite these caveats, which are unavoidable given current knowledge of these syndromes and their largely descriptive nature, experience with classification criteria in other areas of rheumatic disease has shown that criteria can be extremely useful. They help standardize our clinical vocabularies, aid in estimating prognosis, encourage more systematic definition of study patients, and provide a conceptual base against which to assess the merits of new information.
