Global, regional and national burden of pelvic inflammatory disease: trend projections and health inequality analysis, 1990-2021 RUNNING HEAD (maximum 40 characters):The global burden of pelvic inflammatory disease

Qingyu Song¹Zheng Shen²Zhaoyi Jing²Runze Ma³Jing Zhou^4*Hu Li^5*Tianyu Bai^5*

• ¹Shanghai University of Traditional Chinese Medicine, Shanghai, China
• ²Shandong University of Traditional Chinese Medicine, Jinan, China
• ³Shandong First Medical University, Jinan, China
• ⁴Changhai Hospital, Shanghai, China
• ⁵Shandong Provincial Third Hospital, Jinan, China

Background: Pelvic inflammatory disease (PID), a global health challenge, poses a major challenge to women's health and economic development, but has received relatively little research investment and attention.We aimed to assess the global, regional, and national burdens and trends of PID in women from 1990 to 2021. Methods:The Global Burden of Disease (GBD) 2021 standardized methodology was used to analyze the burden of PID at global, regional, and national levels, with attention to the age factor; The indicators covered in this study include prevalence, years lived with disability (YLDs), age-standardized rates (ASR), and estimated annual percentage change (EAPC), accompanied by 95% uncertainty intervals (UI) for the period from 1990 to 2021. Join-point regression was applied to identify turning points in the change in the burden of disease, and in addition, Spearman correlation analyses were used to assess the association between ASR and SDI; the study also involved a cross-countryinequality analysis with decomposition.Finally, Bayesian age-period-cohort modeling was used to predict the disease burden of pelvic inflammatory disease in 2035. Results:PID prevalence and YLDs increased over 32 years, whereas ASPR and ASYR remained relatively stable; the PID burden of disease is concentrated in the 30-39 year age group; countries with lower SDI bear a greater burden of PID, and health inequalities have declined but persist; population growth and aging are driving the burden of PID, with epidemiological changes driving the increase in PID but slowing the rise in YLDs; projections based on the BAPC model suggest that the burden of PID will continue to rise through 2035. Conclusion: From 1990 to 2021, the global burden of pelvic inflammatory disease (PID) exhibited an overall upward trend, a trend that is expected to persist. The population with the highest concentration of PID disease burden is women aged 30–39, and the region with the highest concentration of PID disease burden is low-SDI countries. Consequently, health policies ought to prioritize these populations and regions, integrating sexual health education into fundamental public health services, promoting free screening and early diagnosis and treatment, and fortifying training for frontline healthcare workers and access to contraceptive methods to mitigate the