Reliability assessment and validation of the dermal pigmentation area and severity index: a new scoring method for acquired dermal macular hyperpigmentation

BACKGROUND: Dermal pigmentation area and severity score (DPASI) is a recently proposed scoring system for acquired dermal macular hyperpigmentation (ADMH). OBJECTIVE: To determine the reliability and validity of DPASI. METHODS: After standardized training, three researchers independently rated 55 patients with ADMH on two consecutive days within 1 week, to determine intra-rater and inter-rater reliability. Validation was performed by comparing DPASI with the physician global assessment score. RESULTS: Test-retest reliability of individual raters tested by Pearson's r showed good correlation for all three raters (r = 0.984, P < 0.0001; r = 0.983, P < 0.000 and r = 0.970, P < 0.0001). Inter-rater agreement computed by intra-class correlation coefficient also showed good correlation (ICC = 0.997, P < 0.0001). Internal consistency as measured by Cronbach's alpha was 0.997. The score faired well in face and content validity (I-CVI of 0.87). On usability assessment, the scale had a median score of 4 on a scale from 1 to 5. The meantime taken to score the patients were 307.2 ± 83, 308.9 ± 84.4, 350.15 ± 91.8 s by three observers, respectively. CONCLUSION: The DPASI is a reliable measure of ADMH severity. The use of dermoscopy decreases inter and intra-observer variation resulting in a more objective score.