Background/Purpose: Interstitial lung disease (ILD) is a frequent extraarticular manifestation of rheumatoid arthritis (RA) that imposes substantial economic burden on patients and healthcare systems. However, the impact of the incidence of ILD on healthcare resource utilization (HCRU) and medical cost in RA patients (pts) has not been well documented. The objective of this study was to assess the HCRU and cost attributed to incident ILD in RA pts.

Methods: Adult pts from administrative claims database Optum Clinformatics Data Mart with incident RA (≥2 claims with ICD-9: 714.0 or ICD-10: M05.xxx/ M06.0xx/ M06.8xx /M06.9) between July 2002 to Jun 2018 were included in the analysis. Pts were split into 2 mutually exclusive cohorts of incident RA-ILD pts (Pts having ≥1 ILD diagnosis before and after the chest X-ray/CT scan/Lung Biopsy/Pulmonary Function Test conducted post first RA diagnosis) and RA only patients (no ILD diagnosis in the study period). All-cause healthcare resource use and costs were calculated for the 12 months prior to and 12 months after diagnosis in both cohorts. Statistical differences between the RA-ILD and RA only cohort were assessed using chi-square and Kruskal-Wallis tests with significance level of 0.05.  For the incident RA-ILD cohort, an additional McNemar and Wilcoxon sign rank tests was conducted for the comparion between per and post ILD diagnosis period with significance level of 0.05.

Results: A total of 8,214 incident RA-ILD pts and 104,101 RA only pts were included in the analysis. RA-ILD pts were significantly older, had more comobididities and a lower percentage of female as compared to RA only patients (Table 1). In RA-ILD pts, all healthcare service use including inpatient visits, length of hospital stay, outpatient visits, pharmacy prescriptions increased significantly after the diagnosis of ILD for the RA-ILD cohort, resulting in a 74% increase in all-cause cost. (Table 2) Compared with RA only pts, RA-ILD pts showed a statistically greater increase in overall and all components of healthcare use over the study period (Table 3). The increase of all-cause medical cost was $20,444 higher in RA-ILD pts, primarily driven by the increase in the inpatient and outpatient cost.

Conclusion: RA-ILD pts had a substantial increase in healthcare resource utilization and a nearly doubled medical cost after the diagnosis of ILD. The greater cost was primarily driven by the higher use of inpatient and outpatient service. This indicates the need of more targeted treatment strategy to prevent ILD and improve clinical and economic outcomes of RA-ILD pts.

Table 1

Table 2

Table 3

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/interstitial-lung-disease-associated-health-care-resource-utilization-and-cost-in-rheumatoid-arthritis-patients-in-an-insured-population/