Real-world evidence on palmoplantar pustulosis: patient characteristics, diagnostic challenges and predictive factors for treatment survival - a retrospective registry study.

Abstract

Little is known about the clinical characteristics, diagnostic delay and treatment survival in patients with palmoplantar pustulosis (PPP). To analyse the survival rates of patients with PPP in Austria treated with phototherapy, conventional systemic therapies and biologics. This was a retrospective study using data from the Psoriasis Registry Austria (PsoRA). The analysis included data collected between 16 May 1997 and 11 April 2024 from patients with PPP. We included data from 190 patients who underwent 397 treatments. Fifty-four per cent of patients (n = 37/69) were initially misdiagnosed as having eczema with a mean (SD) diagnostic delay of 2.8 (4.8) years. Patients were predominantly women (n = 141/190; 74.2%) and smoked (n = 76/98; 78%). Patients were treated with biologics (n = 198/397; 49.9%), phototherapy (n = 100/397; 25.2%) and conventional systemic therapies (n = 99/397; 24.9%). Median survival time for all treatments was 0.6 years [95% confidence interval (CI) 0.5-0.8], with patients on ustekinumab having the longest median survival time of 2.7 years (95% CI 2.3-upper limit not reached), surpassing all other therapies. This superiority disappeared after interleukin (IL)-23p19 inhibitors were introduced in Austria. Compared with biologics, conventional systemic treatments [hazard ratio (HR) 2.17; P < 0.001] and phototherapy (HR 4.43; P < 0.001) were associated with a significantly higher risk of treatment discontinuation. In the overall cohort, disease durations of ≥ 2 to < 10 years (HR 0.66; P = 0.05) and ≥ 10 years (HR 0.59; P = 0.004) significantly reduced the risk of treatment discontinuation, while concomitant plaque psoriasis significantly increased the risk of treatment discontinuation (HR 1.43; P = 0.05). In the biologic cohort, concomitant arthritis (HR 2.11; P = 0.002) and the presence of one comorbid disease (HR 2.34; P = 0.03) increased the risk of treatment discontinuation. Furthermore, sex, age at disease onset and smoking did not influence the risk of treatment discontinuation. Our findings suggest that more than half of patients with PPP experience a diagnostic delay of several years due to an initial misdiagnosis. Patients on ustekinumab (IL-12/23p40 inhibitor) had the longest treatment survival, although its superiority diminished with the introduction of IL-23p19 inhibitors. Finally, shorter disease duration and concomitant plaque psoriasis is a general risk factor for treatment discontinuation, while the presence of a comorbidity and concomitant psoriatic arthritis are risk factors for discontinuing biologics.