OBJECTIVES: Osteogenesis Imperfecta (OI) is a group of rare systemic connective tissue disorders resulting in bone fragility and other connective tissue abnormalities. There is minimal evidence on OI epidemiology in Canada. This retrospective observational study in Ontario estimated the prevalence of OI and described clinical characteristics of patients with OI.

METHODS: This study used administrative health data in Ontario held by ICES. Patients with 2 ICD-10-CA OI codes more than 30 days apart between January 1, 2008, and December 31, 2021, were indexed into a Prevalence cohort on their first OI code in the study period. A sensitivity analysis was conducted to understand the prevalence of patients with 1 ICD-10-CA OI code. Patients with ≥1 year of follow-up were further included in a Burden of Illness (BOI) cohort. Patients >105 years or a non-Ontario resident at index, or missing key demographics were excluded.

RESULTS: The Prevalence cohort included 565 patients, with a median (IQR) age of 14 (5, 37) years, and 48% were male. Prevalence was stable between 2017 to 2021 at 3.9/100,000. When using 1 ICD-10-CA OI code, prevalence ranged from 10.6-11.8/100,000 during these years.

CONCLUSIONS: This study estimates OI prevalence in Ontario at almost 4 cases per 100,000, which may be an under-estimate given the limited capture of diagnoses in administrative data. Patients with OI commonly experience comorbidities and complications, namely fractures, which may pose significant burden to patients and the healthcare system.