MEASURING SHOULDER FUNCTION WITH THE SHOULDER PAIN AND DISABILITY INDEX

Objective. To extend the validity of the Shoulder Pain and Disability Index (SPADI) by (1) making it suitable for telephone administration; (2) determining its convergent validity with other health status measu res; and (3) assessing the responsiveness of the SPADI to clinical cha nge. Methods, Consecutive primary care patients with shoulder discomfo rt were followed for 3 months. At enrollment, a detailed shoulder spec ific history was obtained by a trained research assistant, and the Hea lth Assessment Questionnaire (HAQ), the Medical Outcomes Study SF-20 ( SF-20), and numeric and visual analog versions of the SPADI were compl eted by the patient. At 2, 4, and 12 weeks the numeric scaled SPADI wa s administered by telephone and patients rated globally the change in shoulder discomfort. Results, One hundred and two subjects were enroll ed; 96 completed at least one followup assessment and 75 completed all followup assessments. Subjects were men (98%), predominantly white (7 3%), with a median age of 60 years, and the majority had experienced s houlder discomfort for >3 months (66%). At baseline the visual analog (VAS) and numeric scaled SPADI were highly concordant (intraclass corr elation coefficient = 0.86), and the SPADI correlated substantially wi th the HAQ (r = 0.61) and the physical functioning (r = -0.50) and pai n (r = -0.43) domains of the SF-20, The SPADI(triangle) (baseline - fo llowup) discriminated accurately between subjects who improved versus those who stayed the same or worsened [receiver operating characterist ic cure, (ROC) = 0.91, likelihood ratio for improvement = 34]. Conclus ion. The numerically scaled SPADI is highly correlated with the origin al VAS version of the SPADI and other measures of health status. The S PADI is responsive to change and accurately discriminates among patien ts who are improved or worsened.