Abstract
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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.