Interstitial Lung Disease Can Be Early Sign of SSc, Study Reports

ILD first found in 4% to 6% of scleroderma patients in US claims database

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Between 4% and 6% of people with scleroderma (SSc) were first determined to have an interstitial lung disease (ILD), according to an analysis of a large U.S. insurance claims database.

This finding supports evidence of scleroderma’s early impact on lung disease, and “underline the importance of clinical examination and serologic [blood] testing in patients presenting with an ILD to exclude autoimmune disease [such as SSc] as the underlying cause,” the researchers wrote.

The study, “Understanding diagnostic pathways in systemic sclerosis and systemic sclerosis-associated interstitial lung disease: A retrospective cohort study,” was published in the journal Medicine.

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ILD is a serious complication for scleroderma patients

ILD, a group of lung conditions characterized by inflammation and fibrosis (scarring) of tissue in and around the lungs’ air sacs, is a serious complication in people with SSc. ILDs are often detected after the diagnosis of a connective tissue disease such as SSc, but they also can be a first manifestation of such diseases.

In certain SSc patients, pulmonary manifestations precede disease symptoms not related to the lungs by several months to, potentially, several years, the study noted.

“Progression of SSc-ILD is associated with a significant increase in mortality,” the researchers, who included several investigators working for Boehringer Ingelheim Pharmaceuticals, noted. “Early identification of SSc-ILD is important to enable patients to receive prompt treatment to slow progression and improve outcomes.”

To further understand the diagnostic path of ILDs among scleroderma patients in the U.S., the team analyzed data — covering January 2007 to June 2019 — from a large U.S. insurance claims database, the Optum’s Clinformatics Data Mart Database. It contains data, stripped of identifying information for the analysis, from commercial and Medicare Advantage claims covering more than 60 million people in the U.S.

Patients were divided into two groups, according to the version of the International Classification of Diseases, Clinical Modification, used as a diagnostic tool. Specifically, patients were diagnosed following the ICD-9-CM (ninth revision, used until October 2015) or the ICD-10-CM  group (the tenth and current revision).

In total, the ICD-9-CM group comprised 1,779 adults and the ICD-10-CM group 1,032 adults. In both groups, patients had two or more medical claims associated with SSc on different dates within a year. In the ICD-9-CM group, patients had three or more years of continuous enrollment in the database prior to their first insurance claim due to SSc, called an index date. In the ICD-10-CM group, patients had at least two years of enrollment.

The existence of an ILD diagnosis was defined as two or more medical claims associated with an ILD on different dates. An ILD finding prior to SSc was determined through a second ILD claim filed by a patient before a first, or index, claim for SSc.

Patients had a mean age of 60.8 in the ICD-9-CM group and of 65 in the ICD-10-CM group at the time of their first SSc claim. In both groups, over 80% of patients were female and around 65% were white.

The researchers also investigated the rate of ILD prior to a SSc diagnosis using data from the anonymized US-based Cerner Health Facts database, collected from January 2000 to September 2018. Of note, data from the Cerner database are extracted from electronic medical records.

In total, 4,969 patients were identified in the Cerner database, of whom 476 patients had three or more years of medical history prior to their first SSc-related encounter and were part of the Cerner ICD-9-CM group. They had a mean age of 58.4 at the time of their first SSc diagnosis, 91.8% were female and 75% were white.

In the Optum database, a second ILD medical claim prior to the SSc index date was recorded for 136 patients in the ICD-9-CM group (7.6%) and 96 patients of the ICD-10-CM group (9.3%). Also, 76 patients (4.3%) in the ICD-9-CM group and 58 patients (5.6%) in the ICD-10-CM group had their second ILD medical claim more than one year before a first SSc claim. In the Cerner ICD-9-CM group, this was seen for 16 patients (3.4%).

Based on the Optum database, no significant differences in age were seen among patients who had ILD claims prior to or after SSc claims.

Lung disease specialists, general hospital providers, and radiologists were the most common healthcare professionals submitting first or second ILD claims. The most frequent procedures were X-rays (22.4%) and breathing capacity tests (15.8%).

Overall, “analyses of a large US health insurance database showed that 4% to 6% of patients with SSc had claims for ILD [over] 1 year prior to a claim for SSc,” the researchers wrote.

“These data provide further evidence that SSc can affect the lung at an early stage of SSc and reinforce the importance of screening patients with SSc for ILD and patients with ILD for SSc,” they concluded.

Boehringer Ingelheim markets Ofev (nintedanib), an approved treatment for SSc-ILD, and the company funded this analysis.