1990 Criteria for the Classification of Polyarteritis Nodosa Tree Format

PAN subsets

3. Neuropathy and weight loss >6.5 kg; negative arteriogram and artery biopsy

4. Positive artery biopsy and neuropathy; negative arteriogram

6. Positive arteriogram, male sex; normal AST and ALT

7. Positive arteriogram and abnormal AST and ALT

Non-PAN subsets

1. Negative arteriogram and no neuropathy

2. Neuropathy; negative arteriogram and artery biopsy; weight loss ≤6.5 kg

5. Positive arteriogram; normal AST and ALT; female sex

* The subset numbers also appear below the subset boxes in Figure 1. Missing data rules: If angiogram not available, substitute vessel biopsy (first surrogate); if this is not defined, substitute testicular pain/tenderness (second surrogate); analogous rule is to be applied for the other dividing variable whose surrogates are provided (see Figure 1). The classification tree yields a sensitivity of 87.3% and a specificity of 89.3%. AST = aspartate aminotransferase; ALT = alaninie aminotransferase. See Table 2 for definitions of criteria.