Reliability assessment and validation of the postacne hyperpigmentation index (PAHPI), a new instrument to measure postinflammatory hyperpigmentation from acne vulgaris.
BACKGROUND
There are no validated outcome measures for postinflammatory hyperpigmentation (PIH).


OBJECTIVE
We sought to determine the reliability and validity of an outcome measure for PIH after acne in patients with skin of color.


METHODS
A postacne hyperpigmentation index (PAHPI) was developed. Six raters scored 21 patients with PIH twice. Reliability was determined within and between raters, whereas validity was evaluated by comparing scores with severity ranking by an independent dermatologist. The pigment intensity scores were compared with the melanin index of each patient using a narrowband reflectance spectrophotometer. A quality-of-life score (Skindex-29) was also compared with PAHPI scores.


RESULTS
Total PAHPI scores showed good reliability within and between raters and were valid when compared with clinical severity and melanin indices. Good correlation was achieved between the total PAHPI score and the emotion subscale of the Skindex-29.


LIMITATIONS
Generalizability of results is limited to African American females.


CONCLUSION
The PAHPI shows good reliability and validity when scored on patients with PIH from acne vulgaris. The PAHPI also correlates well with the emotional impact of PIH as measured by the Skindex-29. Future studies should assess the ability of the PAHPI to change with improvement of PIH from acne after treatment.
['Savory|Stephanie A|SA|', 'Agim|Nnenna G|NG|', 'Mao|Rui|R|', 'Peter|Shayna|S|', 'Wang|Casey|C|', 'Maldonado|Gerardo|G|', 'Bearden Dietert|Jessica|J|', 'Lieu|Tiffany Jane|TJ|', 'Wang|Christy|C|', 'Pretzlaff|Kara|K|', 'Das|Shinjita|S|', 'Vandergriff|Travis|T|', 'Lopez|Isha E|IE|', 'Litzner|Brandon R|BR|', 'Hynan|Linda S|LS|', 'Arellano-Mendoza|Maria Ivonne|MI|', 'Bergstresser|Paul R|PR|', 'Pandya|Amit G|AG|']
D000152:Acne Vulgaris D000293:Adolescent D000328:Adult D001741:African Americans D044466:Asians D003872:Dermatitis D005260:Female D006630:Hispanic or Latino D006801:Humans D017495:Hyperpigmentation D008297:Male D008543:Melanins D015588:Observer Variation D011788:Quality of Life D015203:Reproducibility of Results D012720:Severity of Illness Index D013053:Spectrophotometry D055815:Young Adult
validation postacne hyperpigmentation index hyperpigmentation PAHPI postinflammatory postinflammatory hyperpigmentation acne vulgaris outcome measures PIH skin of color pigment pigment ICC Spearman rank order correlation clinical trials evidence-based medicine intraclass correlation coefficient pigmentation postinflammatory hypermelanosis rho