# A severe course in paediatric acute haematogenous osteomyelitis: Predictor variables present on admission

## TL;DR

This study identifies risk factors on admission that predict a severe course in children with acute haematogenous osteomyelitis.

## Contribution

The study introduces four admission-based predictors for severe disease progression in pediatric osteomyelitis.

## Key findings

- Admission to the ICU increases the risk of a severe course by 2.8 times.
- CRP >250 mg/L on admission raises the risk of a severe course by 1.7 times.
- Involvement of more than one bone segment increases the risk by 2.4 times.

## Abstract

A subset of children with acute haematogenous osteomyelitis become severely ill. This study aimed to define a severe and standard course and identify potential risk factors on admission for a severe course as well as the cumulative incidence.

This retrospective cohort study included all children under 16 years with acute haematogenous osteomyelitis between January 2018 and September 2021. The outcome parameters included >2 surgical debridements, C-reactive protein level not halving in 48 h, extraosseous involvement and hospital stay >14 days. Predictor variables (delayed presentation (>5 days), C-reactive protein >250 mg/L on admission, >1 bone segment and need for intensive care unit on admission) were tested against the outcome of a severe clinical course using univariate logistic regression analysis (using p < 0.2).

One hundred and twenty-one patients were included. Thirty-nine patients (32.2%) had a complicated course. Patients admitted to intensive care unit had a 2.8-times higher risk of a severe course compared to those not requiring intensive care unit (risk ratio 2.8; 95% confidence interval 1.6–4.8); having a C-reactive protein >250 mg/L on admission increased the risk of a severe course 1.7 times (risk ratio 1.71, 95% confidence interval 1.3–2.3). Having more than one bone segment involved and a delayed presentation of >5 days increased risk of a severe course by 2.4 (risk ratio 2.4, 95% confidence interval 1.6–3.6) and 1.3 times (risk ratio 1.3, 95% confidence interval 1.3–1.3), respectively, compared to the alternative. The cumulative incidence of acute haematogenous osteomyelitis ranged between 4.0% and 5.0% per year.

Four risk factors present on admission were identified and are suggested to modify the risk of a severe disease as well as change treatment protocols.