Risk of Chronic Obstructive Pulmonary Disease in Rheumatoid Arthritis: A Population Based Cohort Study

Katherine McGuire¹, J Antonio Avina-Zubieta², Eric C. Sayre¹, JM Esdaile³ and Diane Lacaille⁴, ¹Arthritis Research Canada, Richmond, BC, Canada, ²Arthritis Research Canada / University of British Columbia, Vancouver, BC, Canada, ³Rheumatology, Arthritis Research Canada, Richmond, BC, Canada, ⁴Arthritis Research Centre, University of British Columbia, Vancouver, BC, Canada

Meeting: 2015 ACR/ARHP Annual Meeting

Date of first publication: September 29, 2015

Keywords: Copd, longitudinal studies, population studies, rheumatoid arthritis (RA) and risk

Session Information

Date: Sunday, November 8, 2015

Title: Epidemiology and Public Health Poster I: Comorbidities and Outcomes of Systemic Inflammatory Diseases

Session Type: ACR Poster Session A

Session Time: 9:00AM-11:00AM

Background/Purpose:

A link between chronic obstructive pulmonary disease (COPD) and inflammation has been established in a number of studies. This raises the question of whether chronic inflammatory conditions, such as RA, predispose to COPD. The objective of this study was to evaluate the risk of incident COPD in RA compared to the general population.

Methods:

We conducted a retrospective cohort study of a population based incident RA cohort, identified between 1996-2006 and followed until 2010, using administrative health data. All incident RA cases in British Columbia were selected using previously published criteria. Controls were randomly selected from the general population, matched 1:1 to RA cases on birth year, gender and calendar year of inclusion. Individuals with inpatient or outpatient visits for COPD prior to index date were excluded. COPD outcome was defined as a hospitalization with a COPD code, which has been validated. All data were obtained from the Ministry of Health, including all visits to physicians, hospitalizations and dispensed medications.

Incidence rates and 95% CI were calculated for the RA cohort and controls, along with incidence rate ratios (IRR). Multivariable Cox proportional hazard models (PHM) were used to estimate the risk of COPD in RA compared to the general population after adjusting for potential confounders. Sensitivity analyses were performed to test the robustness of the results to the possible confounding effect of smoking, as it is a risk factor for both RA and COPD unavailable in administrative data, assuming a prevalence of 10% or 20% and an OR of 1.3 or 3.0, which covers the smoking rate of 16% for BC and of 12.5% observed in our prior RA survey.

Results:

The population cohorts included 24625 RA cases (67% female; mean [SD] age 57.2[17.1] years) and 25537 controls contributing 170401 and 184416 person-years of follow-up, respectively. The incidence rate of COPD was greater in RA than controls (Table 1), yielding an IRR of 1.75. After adjusting for potential confounders, RA cases had a 42% greater risk of developing COPD than controls (Table 1). The increase in risk did not differ according to age or gender. The increased risk in RA remained significant after modelling for smoking.

Conclusion:

In our population-based cohort, individuals with RA had a 42% greater risk of developing COPD compared to the general population. This has important clinical implications for clinicians and people living with RA, supporting good control of inflammation, smoking cessation, and testing for COPD, as indicated.

Table 1: Risk of COPD in RA compared to general population controls

	RA cohort (N=24625)		Controls (N=25537)
No. of incident cases of COPD	892		551
Incident rate of COPD per 1000 patient-years	5.23		2.99
Incident rate ratio (95% CI), RA vs. controls	1.75 (1.57-1.95)
	aHR (95% CI) for COPD
PHM adjusted for age and sex RA vs. general population	1.70 (1.53-1.89)
PHM adjusted for baseline GC use, no. physician visits, prior hospitalizations, asthma, cardiovascular disease and hyperlipidemia, in 1 yr prior to index date RA vs. general population	1.42 (1.27-1.60)
Multivariable PHM stratified by gender RA vs. general population	Males	1.42 (1.19-1.69)
	Females	1.45 (1.25-1.68)
Multivariable PHM stratified by age RA vs. general population	<60 years	1.53 (1.15-2.03)
	>60 years	1.37 (1.20-1.56)
PHM Sensitivity Analyses modeling potential confounding effect of smoking, RA vs. general population controls	Prev.:10% OR: 1.3	1.39 (1.23-1.56)
	Prev.:10% OR: 3.0	1.23 (1.10-1.39)
	Prev.:20% OR: 1.3	1.41 (1.26-1.59)
	Prev.:20% OR: 3.0	1.14 (1.01-1.29)

Abbreviations: GC= Gluococorticosteroids, aHR=adjusted Hazard Ratio, CI= Confidence Intervals

Disclosure: K. McGuire, None; J. A. Avina-Zubieta, None; E. C. Sayre, None; J. Esdaile, None; D. Lacaille, None.

To cite this abstract in AMA style:

McGuire K, Avina-Zubieta JA, Sayre EC, Esdaile J, Lacaille D. Risk of Chronic Obstructive Pulmonary Disease in Rheumatoid Arthritis: A Population Based Cohort Study [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/risk-of-chronic-obstructive-pulmonary-disease-in-rheumatoid-arthritis-a-population-based-cohort-study/. Accessed .

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