The Nail Psoriasis Severity Index (NAPSI): Validation of an Instrument to

Assess Psoriatic Nail Involvement

Julie Jefferson1, Racheal Manhart2, Jill Moore3

Richard Scher4, Phoebe Rich5

• 1Dermatology, Johns Hopkins Medicine, Baltimore,

• 2Research, Oregon Dermatology and Research Center, Portland,

• 3Dermatology, Weill Cornell Medical College, New York,

• 4Dermatology, Oregon Health and Science University, Portland,

United States

Disclosure of interests

I hereby declare the following conflicts of interest:

• J. Jefferson: None Declared;

• R. Manhart: None Declared;

• J. Moore None Declared

• R. Scher is consultant for: Hallux, Meiji, Medimetriks, Moe Medical Devices, Viamet;

• P. Rich received grant/research support from: Abbvie, Allergan, Amgen, Anacor, Boehringer Ingelheim, Cassiopea, Centocor, Celgene , Celtic, Cipher, Creabilis, Cutanea, Demira, Dow, Dusa, Idera, Intendis, Eli Lilly, Galderma, Janssen, Leo, Meiji, Merck, Merz, Mylan, Nano-Bio, Nitric Bio, Novum, Neothetics, Novartis, Novo Nordisk, Nycomed, Oat, Otsuka, Perrigo, Promius, Pfizer, Psolar, Quinnona, Ranbaxy, Sandoz, Stiefel, Tolmar, Tolima, Topica, Valeant, Viamet, Warner Chilcott, Xoma;

• P. Rich is consultant for: Abbvie, Anacor, Meiji, Novartis, Polichem, Valeant;

Authors Note: All photos are were collected by Dr. Rich in her private practice setting as part of standard of treatment and were de-identified to protect patient confidentiality. Additional graphics are not copywriter and were created for use of this presentation.

NAPSI: Introduction

For over a decade the Nail Psoriasis Severity Index (NAPSI) has been the primary grading tool utilized in clinical trials and other studies (Rich, 2003). Despite NAPSI’s widespread use, no single study has been performed to assess this tool for both inter- and intra-rater reliability (Aktan, 2006; Kacar, 2008).

NAPSI: ObjectiveTo determine inter- and intra-rater reliability of the NAPSI.

Eight graders were separately shown an 80-slide PowerPoint presentation with each slide containing a photo of a single psoriatic fingernail.

For each photograph the NAPSI was utilized and scores were recorded for nail bed, nail matrix, and overall severity.

The graders then scored a second PowerPoint presentation containing the same photographs in random order, yielding 2 sets of data per grader.

NAPSI: Materials & Methods

Nail Matrix Psoriasis Features: Pitting

leukonychia,red spots in the lunula,

nail plate crumbling

Score for Matrix: _________1= at least 1 sign present in 1/4 nail quadrants2= at least 1 sign present in 2/4 nail quadrants3= at least 1 sign present in 3/4 nail quadrants4= at least 1 sign present in 4/4 nail quadrants

Photo depicts nail pitting in 4/4 nail quadrants

NAPSI Grading System

Nail Bed Psoriasis:onycholysis,

splinter hemorrhages,oil drop discoloration,

nail bed hyperkeratosis

Score for Bed: _________1= at least 1 sign present in 1/4 nail quadrants2= at least 1 sign present in 2/4 nail quadrants3= at least 1 sign present in 3/4 nail quadrants4= at least 1 sign present in 4/4 nail quadrants

NAPSI Grading System Cont.

Picture depicts oil drop, onycholysis and splinter hemorrhages in 3/4 nail quadrants score of 3.

Total NAPSI Score for one Nail: 3 = (1 + 2)

Individual Nail Score= (Matrix Score + Bed Score)A signal quadrant can contain multiple matrix features, multiple bed features, or both matrix and bed features. To derive an individual nail score, confirm or deny the presence of any nail matrix or nail bed feature within each quadrant- not the quantity of specific features within a quadrant. For example, if both pitting and leukonychia are present in a quadrant, the score would be 1. The Individual Nail Score can range from 0 to 8.

Total NAPSI Score for all 10 Nails: 21 Total Score= (Add up all 10 Individual Nail Scores)The Total Score can range from 0-80

NAPSI: Results

Inter-rater reliability:

Intra-class correlation coefficients (ICC) Time 1: 0.785; Time 2 ICC: 0.790; Average ICC0.825.

Cronbach’s alpha; Time 1: 0.970 ; Time 2: 0.970; Overall 0.977.

All Spearman’s rhos, p < 0.001; Time 1: 0.789 (SD ±0.078 (Range 0.603-0.930); Time 2 0.784 (SD ± 0.074; (Range 0.645-0.883); Overall 0.827 (SD ±0.065; (Range 0.708-0.916).

Intra-rater reliability:

Largest canonical correlation: 0.9925.

Spearman’s rhos per grader: ; p< 0.001; Range 0.831-0.980

NAPSI: Conclusion

The NAPSI is a reliable tool as excellent agreement was demonstrated among graders, as well as, for individual graders.

Strong inter-rater reliability was demonstrated between graders by high ICC’s, spearman’s rho of large magnitudes, and very strong Cronbach’s alpha values.

Strong intra-rater reliability was demonstrated by canonical correlation and spearman’s rho by graders at two different times. The largest canonical correlation .9925, indicates very high intra-rater agreement and strong Spearman’s Rho calculations are consistent with strong intra-rater reliability.