Statistical analysis
Categorical data were tabulated by prevalence, and Fisher’s exact test
was used for comparisons. All continuous data were non-normally
distributed (evaluated by histograms and QQ-plots), and comparisons were
made by Mann-Whitney U-test and tabulated with median, interquartile
range (IQR) with lower quartiles as 25th percentile and upper quartiles
as 75th percentile and range. For mortality analysis, we followed
patients from the date of tumor diagnosis until death, emigration, or
the end of follow-up (October 1st, 2022). The
Kaplan-Meier method was used to compare the one- and five-year survival
for the children with versus without a prior musculoskeletal
misdiagnosis. All statistical tests were performed under a two-sided
significance level of 0.05. STATA/MP 17.0 was used for the statistical
analysis.
The study was approved by the Danish Data Protection Agency (record
number 1-16-02-214-16). This study followed the Strengthening the
Reporting of Observational Studies in Epidemiology (STROBE) (reporting)
guidelines.