Background/Purpose:

Systemic sclerosis (SSc) is a very rare autoimmune disorder and only very few population-based epidemiological studies described its incidence and prevalence in children. In a nationwide, prospective hospital-based case-series from Finland, the incidence of SSc was 0.05 per 100,000 person-years in children aged 0–15 years based on 2 cases (Pelkonen et al. 1994). A field study in the UK by Herrick et al. (2010) that collected SSc cases from all secondary care physicians to whom childhood systemic sclerosis could be referred, reported an estimate of 0.027 cases per 100,00 person-years, based on 7 pediatric SSc cases. For North America, we could not identify any previous study on pediatric SSc epidemiology.

Methods:

We conducted a retrospective cohort study in the MarketScan Commercial Claims and Encounters Database of IBM Watson Health, a large US-based claims database containing data from over 50 million patients from over 150 large employers geographically distributed throughout the US that covers employees and their dependent family members. The database is frequently used for studies in the area of descriptive disease epidemiology. Study period was 01. Jan 2010 until 31. Dec 2015. Following manual review of electronic patient profiles from a sample of patients with SSc claims in MarketScan, cases of SSc were defined using the following minimal-criteria:

• Raynauds Syndrome diagnosis and two SSc outpatient diagnosis (at least 30 days apart) or
• Raynauds Syndrome diagnosis and one SSc inpatient diagnosis or
• Three SSc outpatient diagnoses (two of these diagnosis should be at least 30 days apart) or
• One SSc inpatient diagnosis plus one SSc outpatient diagnosis (on different dates)

Yearly incidence and prevalence estimates and 95% confidence intervals were calculated for each calendar year from 2010 until 2015. Incident cases were required to have no recorded claim of SSc any time before the entry date.

Results:

In the overall pediatric population (<18 years of age), yearly incidence estimates ranged from 0.29 (95% CI: 0.11–0.47) to 0.69 (95% CI: 0.43–0.95) cases per 100 000 person-years, based on 10-27 incident pediatric cases per year. Overall female to male ratio was 2.34 (75/32). Rates were highest in the 12-17 year age group (table 1).

Yearly prevalence ranged from 0.95 (95% CI: 0.78–1.16) to 1.20 (95% CI: 0.95–1.51) per 100 000 children, based on 77-165 prevalent cases per year.

Conclusion:

Pediatric SSc is a very rare disorder. Our study based on a large pediatric population in the MarketScan claims-database in the US yielded higher incidence estimates than those observed previously in smaller studies conducted in Europe. The female/male disproportionality of SSc may be less pronounced in children than known from the adult population.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/systemic-sclerosis-in-pediatric-patients-an-epidemiological-study-in-a-large-insured-population-in-the-us/