Understanding diagnostic pathways in systemic sclerosis and systemic sclerosis-associated interstitial lung disease: A retrospective cohort study

Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is usually detected in a patient known to have SSc but may be diagnosed prior to SSc. We probed an insurance database to investigate documentation of ILD prior to SSc. Using Optum's Clinformatics® Data Mart Database, we identified patients with an SSc index date between January 1, 2010, and September 30, 2015, based on International Classification of Diseases (ICD)-9-Clinical Modification (CM) codes, ≥2 medical claims associated with SSc on different dates within 1 year, and ≥3 years of continuous enrollment prior to SSc index date (ICD-9-CM cohort). We identified an ICD-10-CM cohort comprising patients with an SSc index date between October 1, 2017, and June 30, 2019, based on ICD-10-CM codes, ≥2 medical claims associated with SSc on different dates within 1 year, and ≥2 years of continuous enrollment prior to SSc index date. ILD was defined as ≥2 medical claims associated with ILD on different dates. The ICD-9-CM and ICD-10-CM cohorts comprised 1779 and 1032 patients, respectively. In these cohorts, respectively, 7.6% and 9.3% of patients had their second medical claim associated with ILD prior to their SSc index date, and 4.3% and 5.6% of patients had their second medical claim associated with ILD1 year prior to the SSc index date. In this analysis, 4% to 6% of patients with SSc had claims for ILD1 year prior to a claim for SSc. These data show that SSc can affect the lung early and demonstrate the importance of screening patients with SSc for ILD and patients with ILD for SSc.