Musculoskeletal Diagnoses Prior to Cancer in Children: A Danish Registry-Based Cohort Study.

Objective To identify the prevalence of musculoskeletal diagnoses recorded six months prior to the diagnosis of cancer and to evaluate whether preceding musculoskeletal diagnoses affected survival. Study design We performed a nationwide registry-based cohort study including all children under 15 years of age diagnosed with cancer in Denmark over a 23-year period (1996–2018). The Danish National Patient Registry (DNPR) was used to identify musculoskeletal diagnoses and associated dates recorded within six months preceding the diagnosis of cancer. We compared characteristics of children with and without a prior musculoskeletal diagnoses using prevalence ratios and 95% confidence intervals (CI) and diagnostic interval as median with interquartile range (IQR). We compared survival using Kaplan-Meier and Cox proportional hazards regression analysis adjusting for age, sex, and presence of metastasis at diagnosis. Results Of 3,895 children with all types of cancer, 264 (7%) had a total of 451 hospital visits with musculoskeletal diagnosis within six months preceding the diagnosis of cancer, however, survival was not affected. The overall median diagnostic interval from first musculoskeletal diagnosis (within 6 months before cancer diagnosis) to cancer diagnosis was 15 days (IQR 7–47). Diagnosis of juvenile idiopathic arthritis, unspecified arthritis, and arthropathy each accounted for 5% of the contacts, primarily in children with acute lymphoblastic leukemia, bone sarcomas, or neuroblastomas. Conclusion A preliminary musculoskeletal diagnosis occurred in 7% of children with cancer but did not affect overall survival.