Zhonghua Liu Xing Bing Xue Za Zhi. 2026 Aug 10;47(8):1409-1415. doi: 10.3760/cma.j.cn112338-20251113-00822.
ABSTRACT
Objective: To describe the incidence of primary immune thrombocytopenia (ITP) among children ≤5 years in Chongqing from 2019 to 2024. Methods: A retrospective dynamic cohort of resident children aged ≤5 years was established using data from the Chongqing Health and Medical Big Data Platform between 2019 and 2024. ITP cases were identified using the International Classification of Diseases Tenth Revision (ICD-10) code “D69.3” and regular expression-based keywords matching of Chinese free-text clinical records. New-onset cases were defined using a 90-day washout period. The incidence density of ITP and its 95%CI were calculated using the Poisson distribution. Poisson regression models were used to estimate the associations between incidence density and risk factors including sex, age, residence type, calendar year, and season. Results: A total of 2 608 631 ≤5 years children were enrolled in the cohort, of whom 51.95% were males and 62.50% resided in urban areas. We identified 1 294 new-onset ITP cases, accounting for 1 468 incident episodes. The overall incidence density of ITP was 16.18 per 100 000 person-years (95%CI: 15.37 per 100 000 person-years – 17.03 per 100 000 person-years). The female-to-male incidence density ratio was 0.73, indicating a statistically significant difference (P<0.001). No statistically significant differences in incidence density were observed across calendar years, although a seasonal pattern was noted, with a higher incidence from April to June. The highest risk of ITP was observed among infants, with two peaks in incidence density occurring at 2-3 months and 9 months of age. Incidence density ratio for rural vs. urban children was 0.58 (95%CI: 0.51-0.65) (P<0.001). Conclusion: From 2019 to 2024, the incidence of ITP among children ≤5 years in Chongqing was characterized by a stable temporal trend, a male predominance, a peak in infancy with distinct early-life peaks, and higher incidence in urban populations, along with a moderate seasonal variation.
PMID:42618475 | DOI:10.3760/cma.j.cn112338-20251113-00822
