RESUMEN
BACKGROUND: Keloid scars cause pain, itching, functional limitation, and disfigurement, leading to psychological distress. Progress in treatment regimens is hindered by the lack of a universally accepted outcome measure. The Patient and Observer Scar Assessment Scale is a tool for the assessment of scars, incorporating an assessment by both clinician and patient. This study evaluates its application to keloids and compares it to the widely used Vancouver Scar Scale, which is considered the standard mode of assessment for scars. METHODS: Three observers using the two scales assessed 34 patients with 41 keloid scars independently. Patients evaluated their own scars simultaneously using the patient component of the Patient and Observer Scar Assessment Scale. Internal consistency, interobserver reliability, and convergent validity were examined. RESULTS: Both components of the Patient and Observer Scar Assessment Scale had high internal consistency (0.82 and 0.86 for patient and observer components, respectively); those rates were higher than the rate for the Vancouver Scar Scale (0.65). Interobserver reliability was "substantial" for the Vancouver Scar Scale (0.65) and "almost perfect" for the observer component of the Patient and Observer Scar Assessment Scale (0.85). Convergent validity was very strong (0.83, p < 0.01), although the patient component did not correlate well with either of the observer scales. Patients rated their scars worse than the observer average for 83 percent of the scars, and were influenced by color, stiffness, thickness, and irregularity (p < 0.05). CONCLUSION: The findings support the use of the Patient and Observer Scar Assessment Scale as a reliable and valid method of assessing keloid scars in a clinical context. CLINICAL QUESTION/LEVEL OF EVIDENCE: Diagnostic, II.