A connective tissue disease screening questionnaire for population studies

To develop a technique to screen populations for potential connective tissue disease (CTD), we mailed a 30-item questionnaire to 253 randomly selected patients with systemic lupus erythematosus, rheumatoid arthritis, scleroderma, polymyositis, dermatomyositis, mixed connective tissue disease (MCTD), or Sjögren's syndrome and to 340 randomly selected control subjects. The response rate after four mailings was 71% for case subjects and 54% for control subjects. Test-retest reliability for detection of any CTD was 0.82. Sensitivity for specific CTDs was 83 to 96% and specificity was 83 to 93%. The positive predictive value for any CTD (assuming an overall prevalence of 1.3%) was 5.5%; negative predictive value was 99.7%. The CTD Screening Questionnaire has high sensitivity and specificity for screening large populations.