Supplementary Material for: Epidemiology of pruritus - Global burden of disease research from 1990 to 2021 and future trend predictions

Background: Pruritus, the most common dermatological symptom, lacks comprehensive global epidemiological data. This study analyzed pruritus trends from 1990 to 2021 using the Global Burden of Disease (GBD) 2021 dataset to inform prevention strategies.
Methods: Data on pruritus incidence, prevalence, and disability-adjusted life years (DALYs) were extracted. Temporal trends were assessed using joinpoint regression, while age-period-cohort modeling evaluated age, period, and cohort effects. Socio-demographic index (SDI) correlations and future trends were analyzed using spline models and autoregressive integrated moving average projections.
Results: In 2021, 80.65 million individuals [95% uncertainty interval (UI): 72.30-89.30 million] were affected by pruritus, with 62.53 million new cases [95% confidence interval (CI): 55.87-70.33 million], doubling since 1990. The age-standardized prevalence rate (ASPR) and incidence rate (ASIR) showed annual increases of 0.3352% (95% CI: 0.3247-0.3456) and 0.3168% (95% CI: 0.3063-0.3272), respectively. Higher SDI regions had lower pruritus burdens. The highest risk occurred in the 80–84 age group, with incidence and cohort effects steadily rising. By 2050, ASIR, ASPR, and ASDR are projected to reach 939.33, 1194.41, and 12.52 for females, and 716.82, 933.25, and 9.90 for males.
Conclusion: Pruritus burden has steadily increased over three decades, with the elderly most affected. As the global population ages, targeted strategies are essential to mitigate its growing impact.