Background and objective: There are few population-based longitudinal studies on the relationship of the single breath nitrogen (SBN2) test (which functionally explores the small airways) with pulmonary diffusing capacity for carbon monoxide (DLCO). This study aimed to evaluate whether the slope of phase 3 (N2-slope) from the SBN2 test may predict DLCO and DLCO/alveolar volume (KCO) decline, and whether the N2-slope and DLCO are related to COPD incidence. Methods: Participants from an observational longitudinal population study underwent a SBN2 test at baseline, and DLCO and spirometry at both baseline and follow-up, 8 years apart. Multivariable regressions adjusted for sex, age, height, and smoking status were run: (1) linear regression to assess the association between N2-slope and DLCO or KCO decline; (2) logistic regression to assess the association between patterns of baseline normal/abnormal N2-slope/DLCO and COPD incidence (both GOLD and ATS-ERS criteria). Results: Six hundred and eighty-seven participants (54.6% males, mean age 37.0 years) showed a mean DLCO decline of -0.12 ± 0.76 mL/mmHg/min/year, a mean KCO decline of -0.03 ± 0.12 mL/mmHg/min/L/year, COPD incidence of 9.0% (GOLD) and 3.9% (ATS-ERS). The N2-slope was significantly associated with DLCO and KCO decline (-0.137 mL/mmHg/min/year and -0.014 mL/mmHg/min/L/year, respectively, for a one-unit change in N2-slope). Participants with abnormal N2-slope and DLCO had the highest risk of developing COPD as measured by GOLD and ATS-ERS criteria (RR 4.42, 95% CI 1.20-16.26, and 6.68, 95% CI 1.48-30.23, respectively). Conclusion: In this longitudinal population study, the N2-slope is a predictor of DLCO and KCO decline, and abnormal N2-slope combined with abnormal DLCO is related to COPD development.
Small Airways and Pulmonary Diffusing Capacity Decline in an 8‐Year Longitudinal Population Study
Carrozzi, Laura;Pistelli, Francesco
2025-01-01
Abstract
Background and objective: There are few population-based longitudinal studies on the relationship of the single breath nitrogen (SBN2) test (which functionally explores the small airways) with pulmonary diffusing capacity for carbon monoxide (DLCO). This study aimed to evaluate whether the slope of phase 3 (N2-slope) from the SBN2 test may predict DLCO and DLCO/alveolar volume (KCO) decline, and whether the N2-slope and DLCO are related to COPD incidence. Methods: Participants from an observational longitudinal population study underwent a SBN2 test at baseline, and DLCO and spirometry at both baseline and follow-up, 8 years apart. Multivariable regressions adjusted for sex, age, height, and smoking status were run: (1) linear regression to assess the association between N2-slope and DLCO or KCO decline; (2) logistic regression to assess the association between patterns of baseline normal/abnormal N2-slope/DLCO and COPD incidence (both GOLD and ATS-ERS criteria). Results: Six hundred and eighty-seven participants (54.6% males, mean age 37.0 years) showed a mean DLCO decline of -0.12 ± 0.76 mL/mmHg/min/year, a mean KCO decline of -0.03 ± 0.12 mL/mmHg/min/L/year, COPD incidence of 9.0% (GOLD) and 3.9% (ATS-ERS). The N2-slope was significantly associated with DLCO and KCO decline (-0.137 mL/mmHg/min/year and -0.014 mL/mmHg/min/L/year, respectively, for a one-unit change in N2-slope). Participants with abnormal N2-slope and DLCO had the highest risk of developing COPD as measured by GOLD and ATS-ERS criteria (RR 4.42, 95% CI 1.20-16.26, and 6.68, 95% CI 1.48-30.23, respectively). Conclusion: In this longitudinal population study, the N2-slope is a predictor of DLCO and KCO decline, and abnormal N2-slope combined with abnormal DLCO is related to COPD development.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
