Musculoskeletal Diagnoses before Cancer in Children: A Danish Registry-Based Cohort Study

Objective To identify the prevalence of musculoskeletal diagnoses recorded 6 months before 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 was used to identify musculoskeletal diagnoses and associated dates recorded within 6 months preceding the diagnosis of cancer. We compared the characteristics of children with and without a prior musculoskeletal diagnoses using prevalence ratios and 95% CI and diagnostic interval as median with 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 3895 children with all types of cancer, 264 (7%) had a total of 451 hospital visits with musculoskeletal diagnosis within 6 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 days). A 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. Conclusions A preliminary musculoskeletal diagnosis occurred in 7% of children with cancer, but did not affect the overall survival.