Rheumatoid interstitial lung disease in Canterbury, Aotearoa New Zealand - A retrospective cohort study

Hamish J Farquhar; Lutz Beckert; Adriene L Edwards; Eric L Matteson; Christopher M A Frampton; Edward Ganly; Renee Yetton; Rennae Thiessen; Janine Haslett; Danielle Bucknall; Lisa K Stamp

doi:10.1016/j.semarthrit.2023.152359

Rheumatoid interstitial lung disease in Canterbury, Aotearoa New Zealand - A retrospective cohort study

Semin Arthritis Rheum. 2024 Feb:64:152359. doi: 10.1016/j.semarthrit.2023.152359. Epub 2023 Dec 23.

Affiliations

¹ Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand. Electronic address: hamish.farquhar@cdhb.health.nz.
² Department of Medicine, University of Otago Christchurch, Christchurch, New Zealand.
³ Respiratory Department, Te Whatu Ora Waitaha, Christchurch, New Zealand.
⁴ Division of Rheumatology and Department of Health Sciences Research, Mayo Clinic College of Medicine and Science, Rochester, MN, USA.
⁵ Radiology Department, Te Whatu Ora Waitaha, Christchurch, New Zealand.

PMID: 38157761
DOI: 10.1016/j.semarthrit.2023.152359

Abstract

Background: Rheumatoid arthritis associated interstitial lung disease (RA-ILD), is an important extra-articular manifestation of rheumatoid arthritis (RA). The frequency, risk factors, and prognosis of RA-ILD are incompletely understood.

Aims: To determine the prevalence and incidence, clinical characteristics and risk factors for development, and outcomes of persons with RA-ILD in the population of the Canterbury District Health Board (CDHB) catchment area.

Methods: Individuals aged ≥ 18 years with RA, resident in the CDHB catchment area between 1 January 2006 and 31 December 2008 (Period One), and 1 January 2011 to 31 December 2013 (Period Two) were identified by medical record review and followed until 30 June 2019. Individuals with RA-ILD as defined by pre-specified criteria were identified. The association between demographic and clinical characteristics and RA-ILD development and mortality was examined using Cox-proportional hazards models.

Results: The prevalence of RA-ILD per 100,000 was 10.97 (95 % CI 7.53,14.42) for Period One, and 14.74 (95 % CI 10.84,18.63) for Period Two. Among individuals evaluated for risk factors for RA-ILD development, the estimated cumulative incidence of ILD at 10 years was 4.47 % (95 % CI 3.14, 6.14). After adjusting for age, rheumatoid factor positivity (HR 3.73, 95 % CI, 1.32,10.56), extra-articular manifestations other than RA-ILD (HR 4.48, 95 % CI 2.36,8.48), and subcutaneous rheumatoid nodules (HR 4.66, 95 % CI 2.34, 9.26) were associated with increased risk of developing RA-ILD. The standardised mortality ratio for RA-ILD was 3.90 (95 % CI 2.55,5.72) compared to the general population. Extent of ILD on CT chest was associated with mortality (HR for >20% vs. < 20 % 4.47, 95 % CI 1.67,11.96).

Conclusions: Clinically evident RA-ILD occurred in approximately 5 % of individuals with RA. Mortality was increased almost fourfold compared to the general population. Radiologic extent was the most important prognostic factor.

Keywords: Arthritis; Epidemiology; Interstitial; Lung diseases; Prognosis; Rheumatoid.

MeSH terms

Arthritis, Rheumatoid* / complications
Arthritis, Rheumatoid* / epidemiology
Humans
Lung Diseases, Interstitial* / etiology
New Zealand / epidemiology
Retrospective Studies
Risk Factors