The fractional concentration of exhaled Nitric Oxide (FeNO) as a predictor of death in people with asthma or chronic obstructive pulmonary disease is little understood (COPD). For a study, researchers hypothesized that a FeNO level of more than or equal to 25 ppb was linked with death in a nationwide population of more than or equal to 40-year-old people with asthma or COPD.

FeNO was detected using an electrochemical sensor in the 2007-2012 National Health and Nutrition Examination Survey (NHANES). Through 2015, mortality was calculated via a connection to the National Death Index. Using STATA V.17, a weighted Cox proportional hazards survival analysis was done with the complicated survey design.

During the follow-up period, 5.16% of the 611 individuals with current asthma died. After correcting confounding factors, FeNO more or equal to 25 ppb was linked with a hazard ratio (HR) of 0.20 (P=0.006, 95% CI:0.068-0.618). Because of effect modification, the analysis was performed on those who had and had not had an emergency department (ED) visit for asthma in the previous year. FeNO more or equal to 25 ppb was significantly linked with death in 522 people who did not attend the emergency department (HR 0.094, 95 CI 0.034-0.26, P<0.001). After adjusting for all variables, no significant connection persisted in 83 people with ED visits. (Six people were excluded from this study due to lacking confounder data in the extended regression model.) FeNO more or equal to 25 ppb was not linked with death in 614 COPD patients.

FeNO more or equal to 25 ppb was related to a lower risk of death during follow-up in people with present asthma who had no history of ED visits in the preceding year. In COPD patients, there was no significant correlation between FeNO and death.