FeNO thresholds that rule asthma in and out when spirometry is normal

The edition in brief

Today's pulmonology edition opens with a CHRONICLE analysis in the European Respiratory Journal (22 October) of 480 US adults with severe asthma starting biologics. Exacerbations fell by more than half in real-world use (IRR 0.43), similar to pooled trials. Benefit was larger in patients who met trial criteria for raised FeNO or eosinophils, little smoking and prior exacerbations, while spirometry-based exclusions, which removed the most patients from trials, did not change response. A Norwegian cohort of 16,083 patients with suspected sleep apnoea followed for 15 years (AJRCCM, 1 November) found higher respiratory effort during sleep, measured by oesophageal pressure, was independently associated with mortality beyond the apnoea-hypopnoea index and oxygen saturation. A network meta-analysis of 111 trials of mind-body exercise in stable COPD found yoga, tai chi and traditional Chinese routines improved walking distance and quality of life, with low certainty and mostly Chinese trials. The pearl is checking inhaler technique before escalating. The practice changer is a Lancet Respiratory Medicine meta-analysis (15 September) of 30 studies in suspected asthma with normal spirometry, validated in a primary care cohort. FeNO had good accuracy in adults (AUC 0.80); 65 ppb or more gave a positive predictive value of about 80% at primary care prevalence, and under 20 ppb a negative predictive value of 93%, though 18% of cases were missed. Blood eosinophils were weak and added nothing. Accuracy fell within two weeks of starting inhaled steroids, so test before treating.