Rheumatoid arthritis (RA) is an inflammatory disorder characterized by bone and joint destruction. It has been reported in previous studies that exhaled nitric oxide (NO) is a non-invasive marker of airway inflammation and has been found higher in many diseases. In the present study author compare the NO parameters between subjects with RA to healthy control subjects, and showed significant differences between subjects with RA and matched healthy control subjects regarding the exhaled NO parameters. 

Rheumatoid arthritis (RA) is an autoimmune problem recognised by joint and bone disruption, but other organ systems can also be affected. According to the recent studies, RA may also affect the lungs. Exhaled nitric oxide (FENO) is considered as one of the markers of inflammation. The study compares the NO parameters within RA and healthy control subjects and assess whether the NO parameters associated with the functioning of lungs and disease activity among RA patients.

Individuals were selected at the time of their routine outpatient visits to the rheumatology department. An algorithmic estimation of nitric oxide (NO) parameters (tissue concentration of NO in the airway wall (CawNO), alveolar NO concentration (CANO), and airway compartment diffusing capacity of NO (DawNO) were conducted. Controls involved the healthy participants who matched by gender, height and age. Median was used to represent the data. Group comparison was done by applying the Wilcoxon Matched Pairs test and comparisons between any two groups, and for pairwise comparisons, the Mann-Whitney U test was applied. Further, the Spearman rank order correlation was used to test the associations. 

As compared to healthy subjects, RA patients exhibited significantly lowered CANO and CawNO with higher DawNO. 

A significant difference was between healthy and RA subjects about exhaled NO parameters. It is uncertain if this can be defined by the pathogenesis of RA, outcomes of long-term disease, and/or due to drug therapy.