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Background: Persons with rheumatoid arthritis (RA) have an increased risk of interstitial lung disease (ILD). ILD is a serious extraarticular manifestation in RA with a significantly increased mortality but without evidence-based drug therapy (1).
Objectives: The aim of this analysis was to investigate the frequency of ILD diagnosis in RA using claims data and to identify the medications prescribed.
Methods: Data from a large German statutory health insurance fund were used to identify persons with one inpatient or two outpatient diagnoses of RA (ICD-10: M05, M06) and ILD (J84.1, J84.8, J84.9 and M05.1+J99.0) in 2019. Specialist care by rheumatologists and/or pulmonologists was identified using physician specialty numbers. Drug prescriptions of glucocorticoids, conventional synthetic disease modifying antirheumatic drugs (csDMARDs: methotrexate, leflunomide, sulfasalazine, hydroxychloroquine, mycophenolate), biologic (b) DMARDs (abatacept, rituximab, TNF inhibitors, tocilizumab) or targeted synthetic (ts) DMARDs (tofacitinib) were identified by ATC codes. Prescriptions were included if a person received at least one prescription of the respective drug in 2019.
Results: Among 7,479,000 persons over 18 years of age and insured in 2019 a total of 2.0% (n=148,000) had a diagnosis of RA and 1.1% (n=1,600) of those had an additional diagnosis of ILD. The majority of persons with RA+ILD diagnosis was older than 70 years (59%), mean age was 72 years, 68% were female and 41% had a diagnosis of serpositive RA (M05). 4 out of 5 patients were in rheumatologist or pulmonologist care (36% both, 22% only rheumatologist, 22% only pulmonologist). In total, 67% received glucocorticoids, 49% csDMARDs and 19% bDMARDs and 1.8% tofacitinib. TNF inhibitors were the most frequently prescribed bDMARDs followed by abatacept and tocilizumab. Persons without specialized care received considerably less DMARD therapy (
Demographics and treatment of persons with RA and ILD diagnosis, numbers are percentages unless indicated otherwise.
| Variable | Not treated by rheumatologist or pulmonologist | Treated by rheumatologist and/or pulmonologist | All |
| N (%) | 326 (20%) | 1274 (80%) | 1,600 (100%) |
| Age, mean years (std) | 75 (10) | 72 (10) | 72 (10) |
| <70 years | 35 | 43 | 41 |
| 70 to 80 years | 31 | 39 | 37 |
| >80 years | 35 | 18 | 22 |
| Female sex | 67 | 69 | 68 |
| Glucocorticoids | 49 | 72 | 67 |
| csDMARDs | 24 | 56 | 49 |
| MTX | 13 | 30 | 27 |
| Leflunomide | 4.9 | 10 | 8.9 |
| (Hydroxy-)chloroquine | 2.8 | 9.0 | 7.8 |
| Mycophenolate | 1.2 | 2.2 | 2.0 |
| Sulfasalazine | 2.1 | 3.8 | 3.4 |
| bDMARDs | 7 | 22 | 19 |
| TNF-alpha Inhibitors | 3.4 | 9.0 | 7.9 |
| Abatacept | 2.1 | 5.6 | 4.9 |
| Tocilizumab | 1.2 | 3.6 | 3.1 |
| Rituximab | 0.9 | 2.9 | 2.5 |
| Tofacitinib | 1.5 | 1.9 | 1.8 |
Conclusion: ILD was diagnosed in one of 100 persons with RA diagnosis. Specialist care is necessary to provide disease-specific therapies. While methotrexate is the most commonly used DMARD, the bDMARD prescription is heterogeneous.
REFERENCES:
[1]Hyldgaard C, Ellingsen T, Hilberg O, Bendstrup E. Rheumatoid Arthritis-Associated Interstitial Lung Disease: Clinical Characteristics and Predictors of Mortality. Respiration. 2019;98(5):455-460.
Acknowledgements: The study was supported by the German Federal Ministry of Education and Research within the network TARISMA [01EC1902A].
Disclosure of Interests: Katinka Albrecht: None declared, Anja Strangfeld: None declared, Ursula Marschall Employee of: Employee of the BARMER statutory health insurance fund, Johanna Callhoff: None declared