# The Brazilian Portuguese version of the psoriasis epidemiology screening tool (PEST-bp) is reliable and accurate: a cross-sectional study from southern Brazil

## TL;DR

A new tool for detecting psoriatic arthritis in Brazil is found to be reliable and accurate.

## Contribution

The study validates the diagnostic accuracy of the Brazilian Portuguese version of the PEST tool for PsA detection.

## Key findings

- A PEST-BP score ≥ 3 showed 81% sensitivity and 79.7% specificity for PsA detection.
- PsA patients had higher prevalence of dactylitis, nail psoriasis, and PASI ≥ 10.
- PEST-BP score ≥ 3 and PASI ≥ 10 were independently associated with PsA in multivariate analysis.

## Abstract

Psoriatic arthritis (PsA) remains diagnostically challenging in clinical practice. The Psoriasis Epidemiology Screening Tool - Brazilian Portuguese version (PEST-BP) offers a potential solution for simplified case identification.

To evaluate the diagnostic accuracy of PEST-BP in detecting PsA among patients with psoriasis in a novel Southern Brazilian population.

In this cross-sectional study, psoriasis patients from a dermatology clinic underwent dual assessment: PEST-BP screening and gold-standard rheumatologic evaluation using CASPAR criteria for PsA diagnosis. Statistical analyses included sensitivity, specificity, and ROC curve determination.

Among 100 patients, 21 (21%) met the CASPAR criteria for PsA. A PEST-BP score ≥ 3 showed the best diagnostic performance with 81% sensitivity, 79.7% specificity, and 80% overall accuracy (AUC = 0.845, p < 0.001). Patients with PsA had a significantly higher prevalence of dactylitis (38.1% vs. 11.4%; p = 0.004), nail psoriasis (66.7% vs. 35.4%; p = 0.01), and Psoriasis Area and Severity Index (PASI) ≥ 10 (42.9% vs. 19%; p = 0.023). In multivariate analysis, a PEST-BP score ≥ 3 (OR = 32.43; p < 0.001) and PASI ≥ 10 (OR = 9.26; p = 0.007) were independently associated with PsA.

Single-center design in a tertiary care hospital and small sample size may overrepresent patients with severe disease.

The PEST-BP is a reliable and accurate tool for PsA screening in Brazilian dermatology settings. Its simplicity and strong diagnostic performance support its integration into routine clinical practice for early PsA detection.