Trends in documenting and coding of child physical abuse in hospitalised children and adolescents in Germany: a nationwide administrative data analysis

Hospital administrative data are widely used to monitor child physical abuse (CPA), but coding is often inconsistent. We described the national frequency and distribution of CPA-related coding in German administrative data and assessed how ICD-10-GM indicators and procedural coding influence ascertainment and temporal trends. We analysed aggregated German hospital data from the InEK data browser (2019–2024, ages 0–17 years), comparing T74.1 with broader indicator sets (a validated algorithm adapted to ICD-10-GM and an extended German set) and capturing procedural safeguarding documentation (OPS 1–945.x). We summarised principal diagnoses among hospitalisations with CPA-related coding and quantified CPA-related coding among admissions with predefined abuse-relevant injuries (fractures, haematomas) in children aged 0–2 years, a group at increased risk of physical abuse. CPA-related diagnostic coding remained rare (< 0.5% of annual admissions excluding procedural codes) but increased from 2019 to 2024, driven mainly by assessment- and psychosocial-context indicators (particularly Z04.5 and Z65), whereas T74.1 was stable or declining. Several low-frequency codes showed pronounced year-to-year variability. OPS 1–945.x—a child-protection assessment of suspected endangerment rather than confirmed abuse—had the highest counts and increased, with a decline in 2022. CPA-related indicators were mainly associated with head injuries, most often traumatic subdural haemorrhage and concussion. Among children with abuse-relevant fractures and haematomas, explicit T74.1 coding occurred in only a small minority, whereas OPS 1–945.x was more frequent. Conclusion : These findings highlight the need for standardised coding guidance, validation of broader code sets, and training on administrative documentation to improve the surveillance value of hospital data. What is Known: • CPA is under-coded in hospital administrative data; T74.1 is rarely used. • Broader ICD/procedure-based definitions can increase case capture. What is New: • German national discharge data (2019–2024) show stable/declining T74.1 with rising Z04.5/Z65 and increasing procedural codes OPS 1–945.x. • Including the broader indicator and procedural codes (e.g., Z04.5, Z65, OPS 1–945.x) reveals a marked shift in how concerns about CPA are documented, with these codes increasingly used alongside or instead of T74.1, particularly among children admitted with abuse-relevant injuries.