PeakPASI as a marker of maximum psoriasis severity: a single‐center, cross‐sectional retrospective and questionnaire‐based study

BACKGROUND: The Psoriasis Area and Severity Index (PASI) is the standard measure for psoriasis severity but reflects only a single time point and may underestimate long-term disease burden. To assess whether the highest-ever recorded PASI (PeakPASI) can serve as a marker of historical disease severity and correlate with treatment burden and comorbidities. PATIENTS AND METHODS: A cross-sectional analysis of 308 psoriasis patients from a German university hospital was conducted. Data on PASI, PeakPASI, therapies, and comorbidities were obtained from self-report and medical records. Group comparisons used non-parametric tests; Poisson regression assessed PeakPASI as a predictor of systemic therapy use and comorbidity burden. RESULTS: Median PeakPASI (11.4 [IQR 5.9-17.0]) exceeded current PASI (2.0 [IQR 1.0-5.1]). PeakPASI ≥ 10 was associated with more systemic therapies (p < 0.001), phototherapy (p < 0.001), smoking (p = 0.021), and diabetes (p = 0.020). PeakPASI correlated with number of systemic (ρ = 0.296), topical therapies (ρ = 0.367), and hospital visits (ρ = 0.186). It significantly predicted systemic therapy use (β = 0.355, p < 0.001), but not comorbidity burden. CONCLUSIONS: PeakPASI may complement current measures by reflecting historical severity and informing treatment. While not a cumulative burden marker, it may prevent underestimation of long-term disease impact. Prospective validation is warranted.