Patients with rheumatoid arthritis had a 47% increased risk of hospitalization for COPD
by Nancy Walsh, Senior Staff Writer, MedPage Today October 19, 2017

Action Points
• Patients with rheumatoid arthritis (RA) have a significantly elevated risk of being hospitalized for chronic obstructive pulmonary disease (COPD).
• The study suggests that patients with RA and their physicians, therefore, should be vigilant in looking for early symptoms of COPD so that treatment can begin before permanent damage to the lungs occurs.

Patients with rheumatoid arthritis (RA) have a significantly elevated risk of being hospitalized for chronic obstructive pulmonary disease (COPD), Canadian researchers reported.
In an unadjusted analysis, the incidence rate ratio for risk of COPD admission was 1.58 (95% CI 1.34-1.87) among RA patients compared with controls, according to Diane Lacaille, MD, of the University of British Columbia in Vancouver, and colleagues.
And in a multivariable analysis, patients with RA had a 47% greater risk of admission for COPD (HR 1.47, 95% CI 1.24-1.74) after adjustment for covariates including healthcare visits, prior hospitalization, history of asthma, and use of cardiovascular medications, the researchers reported online in Arthritis Care & Research.
The chronic inflammation characteristic of RA predisposes patients to various comorbidities such as cardiovascular disease, and it is becoming apparent that COPD is an additional potential comorbidity, with several studies having identified an association between COPD and inflammation.
This has been shown by observations that, as with RA, patients with COPD have elevated C-reactive protein, tumor necrosis factor-α, and fibrinogen levels, higher erythrocyte sedimentation rates, and develop autoantibodies.
“Furthermore, studies have shown that inflammatory mediators, such as interleukin (IL)-32 and IL-17, and anti-citrullinated protein antibodies, which play a role in RA, may be involved in the pathogenesis of COPD,” Lacaille and colleagues wrote.
Therefore, to assess the risk of COPD in patients with RA, the researchers conducted a retrospective cohort study of all patients in the British Columbia universal healthcare system diagnosed with RA from 1996 to 2006, along with matched controls. The primary outcome was a first hospitalization for COPD.
The study population included 24,625 patients with RA and 25,396 matched controls. Most of the patients were women; mean age at RA onset was 57. Compared with controls, RA patients had higher scores on the Charlson comorbidity index (0.92 versus 0.29), a greater prevalence of asthma (3.4% versus 2.6%), and more cardiovascular drug (30.7% versus 28.9%) and corticosteroid (23.7% versus 3.4%) use.
During 171,751 and 181,670 patient-years of follow-up among cases and controls, respectively, there were 3,826 and 3,410 deaths, with 70 and 64 patients having COPD listed as the primary cause of death. During follow-up, there were 356 and 238 admissions for COPD among cases and controls, respectively, for an incidence rate of 2.07 and 1.31 per 1,000 patient-years, respectively.
On a sex-stratified analysis, women had an increased risk of COPD hospitalization, with an adjusted hazard ratio of 1.61 (95% CI 1.30-1.98), while men did not (HR 1.25, 95% CI 0.95-1.66). The increased risk of COPD for women with RA was also reported recently in an analysis of data from the Nurses’ Health Study.
On a multivariable proportional hazard model stratified by age, the risk magnitude among RA patients versus controls diminished with age, declining from 1.87 (95% CI 1.23-2.83) for those ages 45 to 59 to 1.32 (95% CI 1.01-1.72) for those 75 and older. This probably reflected the increased incidence of COPD in the general population at older ages, according to the authors.
In a sensitivity analysis that calculated a risk model for potential confounding by smoking status (information on this was not available in the database), the risk for RA patients remained significantly higher, with odds ratios ranging from 1.3 to 3 depending on smoking prevalence.
“The results of our study have notable implications for the clinical care of RA and COPD,” supporting previous evidence that inflammation is important in multiple conditions and highlighting the need for control of inflammation in RA not only to prevent joint damage but also to lower the risks of cardiac and lung disease, the researchers said.
Patients with RA and their physicians, therefore, should be vigilant in looking for early symptoms of COPD so that treatment can begin before permanent damage to the lungs occurs. “Given the tremendous burden and cost of COPD, this has potential for cost saving to the healthcare system,” Lacaille and colleagues wrote.
They noted that limitations of the study included the lack of information on smoking and the reliance on administrative health data.
“Further research is needed to understand the underlying reasons for the increased risk and to explore the relationships between smoking, autoantibody production, and the risk of RA and COPD, in light of research showing that COPD is associated with increased production of a wide range of autoantibodies, including antibodies to citrullinated proteins,” the team concluded.

The study was funded by the Canadian Institute for Health Research.
The authors reported no financial conflicts of interest.
• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
• Primary Source
Arthritis Care & Research
Source Reference: McGuire K, et al “Risk of incident chronic obstructive pulmonary disease (COPD) in rheumatoid arthritis: a population based cohort study” Arthritis Care Res 2017; doi:10.1002/acr.23410.