Latar Belakang: Psoriatic arthritis (PsA) merupakan inflamasi muskuloskeletal yang progresif. Psoriasis kuku merupakan faktor prediktor kuat PsA dengan prevalensi mencapai 87%. Skor modified nail psoriasis severity index (mNAPSI) merupakan salah satu penilaian derajat keparahan psoriasis kuku dengan reliabilitas interrater yang baik. Beberapa penelitian menunjukkan hubungan antara skor mNAPSI dengan PsA serta kerusakan sendi interfalang distal, sehingga dipikirkan bahwa derajat keparahan kuku dapat dijadikan sebagai penapisan kejadian PsA serta kaitannya dengan aktivitas penyakit PsA.Tujuan: Menilai hubungan derajat keparahan kuku menggunakan skor mNAPSI dengan kejadian PsA dan korelasi skor mNAPSI dengan derajat keparahan PsA menggunakan skor clinical disease activity for psoriatic arthritis (cDAPSA). Sebagai hasil tambahan, dilakukan penilaian korelasi skor psoriasis area severity index (PASI) dan cDAPSA. Secara deskriptif menilai proporsi kelainan psoriasis kuku secara klinis maupun dermoskopi pada pasien PsA dan tanpa PsA.Metode: Penelitian observasional analitik. Setiap subyek penelitian (SP) dengan psoriasis kuku yang telah memenuhi kriteria inklusi dan eksklusi dilakukan perhitungan mNAPSI, diagnosis PsA menggunakan classification criteria for psoriatic arthritis (CASPAR), dan menentukan derajat keparahan PsA dengan cDAPSA. Analisis statistik yang sesuai untuk membuktikan hipotesis penelitian. Nilai p <0,05 dianggap signifikan secara statistik.Hasil: Di antara 34 SP terdapat 15 SP yang mengalami PsA. Hubungan antara skor mNAPSI dengan kejadian PsA dianalisis menggunakan ROC dengan hasil nilai area under ROC curve (AUC) 0,58. Korelasi antara skor mNAPSI dengan cDAPSA adalah 0,217 (p=0,437). Terdapat korelasi positif antara PASI dan cDAPSA (r=0,621; p=0,013). Kelainan kuku terbanyak pada penelitian ini adalah onikolisis (72,6%), leukonikia (19,6%), diikuti dengan oil drop dan crumbling masing-masing 12,8%. Seluruh kelainan kuku lebih mudah dilihat dengan dermoskopi, kecuali pitting dan Beau’s line.Kesimpulan: Skor mNAPSI memiliki hubungan lemah dengan kejadian PsA, sehingga tidak dapat digunakan sebagai penapisan kejadian PsA. Selain itu, mNAPSI memiliki korelasi lemah dengan cDAPSA, sehingga derajat kerusakan kuku tidak mencerminkan derajat keparahan PsA.

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Background: Psoriatic arthritis (PsA) is a progressive musculoskeletal inflammation. Nail psoriasis is a strong predictor of PsA with a prevalence of 87%. The modified nail psoriasis severity index (mNAPSI) score is an objective score for evaluating the severity of nail psoriasis and has excellent interrater reliability. Several studies have shown a correlation between mNAPSI scores and PsA and distal interphalangeal joint damage, so it is thought that the severity of the nail can be used as a screening for the incidence of PsA.

Objective: This study aims to assess the relationship between nail severity using the mNAPSI score with the incidence of PsA and to assess the correlation between the mNAPSI score with PsA severity using the clinical disease activity for psoriatic arthritis (cDAPSA) score. In addition, the correlation between psoriasis area severity index (PASI) and cDAPSA scores was also carried out as additional results. This study also descriptively assessed the proportion of psoriasis nail abnormalities both clinically and dermoscopy in patients with PsA and without PsA.

Methods: This research is an analytic observational. All research data are recorded in the research status. Each subject met the inclusion and exclusion criteria, calculated the mNAPSI score, diagnosed PsA using the classification criteria for psoriatic arthritis (CASPAR) score, and determined the severity of PsA with the cDAPSA score. Appropriate statistical analysis was performed to prove the research hypothesis. P value < 0.05 was considered statistically significant.

Results: Among 34 subject, 15 (44%) experienced PsA. The relationship between the mNAPSI score and the incidence of PsA was analyzed using ROC. Based on this analysis, the area under ROC curve (AUC) value was 0.58. The correlation between mNAPSI and cDAPSA scores was 0.217 (p=0.437). There was a positive correlation between the PASI value and cDAPSA and it was statistically significant (r=0.621; p=0.013). The most common nail abnormalities in this study were onycholysis (72.6%), leukonychia (19.6%), followed by oil drop and crumbling (12.8%). All nail abnormalities are easier to see with dermoscopy, except for pitting and Beau's line.

Conclusion: The mNAPSI score has a weak relationship with the incidence of PsA, so it cannot be used as a screening for the incidence of PsA. In addition, this score also has a weak correlation with the cDAPSA score, so the degree of nail damage does not reflect the severity of PsA.