A model for predicting the likelihood of negative culture results in children with osteoarticular infections.

backgroundBlood and pus culture are still considered standard methods for etiological investigations on osteoarticular infection (OAI) in children, but negative culture results are common and may increase the complexity of disease diagnosis and treatment. This study aims to explore the clinical characteristics and risk factors of culture-negative OAI and construct a prediction model for determining the likelihood of negative culture results.

methodsThis single-center retrospective analysis included pediatric OAI cases diagnosed between 2014 and 2023. Demographic data, clinical features, and laboratory parameters were systematically collected. Comparisons were made between culture-positive and culture-negative groups for both blood and pus cultures. Multivariate logistic regression analysis was performed to identify independent predictors of negative culture results, which were used to develop a nomogram-based predictive model. The discriminatory ability of the model was assessed using receiver operating characteristic curves, while its calibration was evaluated through the Hosmer-Lemeshow goodness-of-fit test and bootstrap calibration plots. The clinical utility of the model was determined using decision curve analysis.

resultsThis study included 345 children diagnosed with OAI: blood culture was performed in 243 cases (38 culture-positive and 205 culture-negative), and pus culture was performed in 230 cases (115 culture-positive and 115 culture-negative). In the blood culture group, C-reactive protein (CRP) was identified as an independent predictor of negative blood culture. Receiver operating characteristic curve analysis based on CRP demonstrated a sensitivity of 73.7% and a specificity of 70.2% for predicting culture results. In the pus culture group, presence of septic arthritis, neutrophil percentage, and CRP level were identified as independent predictors of pus culture outcomes. The nomogram constructed using these predictors demonstrated good discriminative ability, calibration, and clinical utility.

conclusionCRP was identified as a key predictor of negative blood culture results. The presence of septic arthritis, neutrophil percentage, and CRP was identified as a key predictor of negative pus culture results. The nomogram constructed with pus culture predictors had good discrimination and clinical applicability and has potential for the early identification of culture-negative OAI cases in the clinic. This tool could optimize etiological investigation strategies and improve the efficiency of clinical diagnosis.