Low Cardiorespiratory Fitness Is a Significant Indicator of Increased Mortality Among Patients With RA

Low cardiorespiratory fitness (CRF) is a significant contributor to increased mortality among patients with rheumatoid arthritis (RA), even among those with C reactive protein (CRP) concentrations less than 3 mg/L, according to study results published in Rheumatic & Musculoskeletal Diseases.

Investigators assessed the effects of inflammation and reduced CRF on all-cause mortality among patients with RA.

A population-based cohort study was conducted using survey data collected from patients with RA included in the Trøndelag Health Study (HUNT3 2006-2008) in Norway.

Inflammation was determined using CRP concentrations and estimated CRF (eCRF) was calculated using patient-specific factors.

All-cause mortality was assessed by the Norwegian Cause of Death Registry, tracking participants from HUNT3 inclusion until death or December 2018.

 A total of 223 patients with RA and 31,684 individuals without RA (control group) were included in the study.

Patients with RA vs members of the control group demonstrated higher rates of mortality for all causes (24.1% vs 9.9%; P <.001). Both eCRF (P <.001) and CRP concentrations of at least 3 mg/L (P <.001) contributed to increased mortality, with the direct impact of RA being insignificant (P =.19).

In sensitivity analyses including all participants (n=50,787), the direct effect of RA was not statistically significant (0.004; P =.28). However, there were significant indirect effects of RA via CRP levels of at least 3 mg/L (0.003; P <.001) and via eCRF (0.007; P <.001). The total effect of RA was 0.014 (P <.001).

Overall, the negative effect of low CRF on all-cause mortality was about 3 times greater than that of inflammation, as indicated by CRP concentrations of at least 3 mg/L.

This study was limited by its case-control design and lack of RA-specific data.

The study authors concluded, “Our study strongly supports recommendations for development of exercise programmes aimed at improving CRF in persons with RA.”

Disclosure: Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Rheumatology Advisor