Improving the sensitivity of the American College of Rheumatology classification criteria for systemic sclerosis.

OBJECTIVE A large proportion of patients with limited systemic sclerosis (SSc) do not meet the current American College of Rheumatology (ACR) classification criteria for SSc. We undertook this study to determine whether the addition of easily available clinical variables, namely nailfold capillary abnormalities identified using a dermatoscope and visible telangiectasias, could improve the sensitivity of the current ACR classification criteria for patients with limited SSc. METHODS Patients in the Canadian Scleroderma Research Group Registry with skin involvement distal to the metacarpophalangeal joints were identified and divided into two groups according to whether they fulfilled the current ACR classification criteria for SSc or not. Sensitivity of the criteria was calculated. Regression tree analysis was performed to determine whether the addition of nailfold capillary abnormalities identified using a dermatoscope and visible telangiectasias could improve the sensitivity of the criteria. RESULTS One hundred and one (101) patients were included, in majority women with a mean age of 59 (+/- 13). Of these, 68 (67%) met the ACR classification criteria. The sensitivity of the criteria increased from 67% to 99% with the addition of nailfold capillary abnormalities identified using a dermatoscope and visible telangiectasias. CONCLUSIONS The SSc research community would benefit from having better classification criteria to identify patients with limited SSc. The current classification criteria for SSc may be significantly improved by the inclusion of easily identified clinical variables including nailfold capillary abnormalities using a dermatoscope.