Evidence of proximal cutaneous sclerosis and at least 2 of 20 predefined minor criteria are required for a diagnosis of juvenile systemic sclerosis, according to new provisional classification criteria.
Using clinical data from real patients in combination with a consensus-based methodology, Dr. Francesco Zulian of the University of Padua (Italy) and colleagues on the Ad Hoc Committee on Classification Criteria for Juvenile Systemic Sclerosis—a combined effort of the Pediatric Rheumatology European Society, the American College of Rheumatology, and the European League Against Rheumatism—developed the new classification criteria to help standardize the conduct of clinical, epidemiologic, and outcome research for this rare pediatric disease and may alter patient care by enabling earlier, more definitive diagnoses (Arthritis Rheum. 2007;57:203–12).
The lack of standard classification criteria until now “has posed a barrier to the initiation of trials,” according to Dr. Thomas J.A. Lehman of Cornell University, New York, who served on the classification committee. Clearly defined criteria are important for directing physicians who don't have much experience with the disease.
The much-needed juvenile criteria, which will supplant the adult criteria that have been used until now, “will help ensure that everyone included in a study has systemic sclerosis and not another condition or an overlap that may have a different long-term outcome,” Dr. Lehman said in an interview. “For patient management, the criteria will help in convincing physicians that a patient does, in fact, have systemic sclerosis.”
The criteria were developed in three phases, the first of which included the retrospective collection of information on demographic, clinical, and laboratory features of patients diagnosed with systemic sclerosis before age 16 from pediatric rheumatology centers worldwide. Investigators from the participating centers completed standardized case report forms to define organ involvement at the time of diagnosis. Forty-eight signs and symptoms, organized into nine categories were included for consideration.
In phase II, the committee developed questionnaires based on the data collected in phase I and sent them to 14 pediatric and adult rheumatologists with expertise in juvenile systemic sclerosis. The experts were asked to select the parameters essential for classification of the disease, based on their experience. Among the variables with the highest final scores, “those with a prevalence of at least 50% at the time of diagnosis, based on our patient population, were selected as provisional major criteria, and the remaining variables were listed as minor criteria,” the authors explained.
In the third phase, the provisional criteria were evaluated by the same 14 experts in a consensus conference, using the clinical profiles of 160 actual patients with a variety of diagnoses, including 100 from patients with definite juvenile systemic sclerosis collected in phase I. A consensus of at least 80% of the experts was achieved for 127 of 160 patients, 70 of whom were judged as having the disease (all from the phase I group) and 57 as not having it. The 127 patients were then used as the accepted standard for rating the provisional classification criteria with the best statistical performance and highest face validity.
Of 86 different provisional classification criteria tested on the case profiles of the 127 patients, the criterion with the highest ranking was that which required the presence of proximal skin sclerosis/induration and at least 2 minor criteria, which is more restrictive than the adult classification criteria, according to the authors.
Conversely, the minor criteria in the proposed classification are more numerous than those used for adults.
Although validated with actual patient data, the new classification criteria must still undergo validation in external prospective trials, they noted.
Provisional Classification Criteria
Major criterion (Required)
▸ Proximal skin sclerosis/induration of the skin
Minor criteria(At least two are required)
▸ Cutaneous
Sclerodactyly
▸ Peripheral vascular
Raynaud's phenomenon
Nailfold capillary abnormalities
Digital tip ulcers
▸ Gastrointestinal
Dysphagia
Gastroesophageal reflux
▸ Cardiac
Arrhythmias
Heart failure
▸ Renal
Renal crisis
New-onset arterial hypertension
Source: Arthritis Rheum. 2007;57:203–12
▸ Respiratory
Pulmonary fibrosis (high-resolution computed tomography/radiography)
Decreased diffusing capacity for carbon monoxide
Pulmonary arterial hypertension
▸ Neurologic
Neuropathy
Carpal tunnel syndrome
▸ Musculoskeletal
Tendon friction rubs
Arthritis
Myositis
▸ Serologic
Antinuclear antibodies
Systemic sclerosis-selective autoantibodies