Emphysema Severity Index (ESI) Predicts Respiratory Death in a Large Swedish General Population

Abstract

Recently, it has been shown and validated that presence and severity of emphysema on computed tomography could be estimated by a novel spirometry based index, the emphysema severity index(ESI). However, the clinical relevance of the index has not been established. We conducted cox-regression analyses with adjustment for age, smoking, sex, forced expiratory volume in one second (FEV1), forced vital capacity (FVC) to study whether ESI was associated with all-cause, respiratory and non-respiratory 10-year mortality. Study population was all participants with acceptable spirometry from the Gott Åldrande i Skåne study, a Swedish general population aged 65-102 years old. ESI is expressed as a continuous numeric parameter on a scale ranging from 0 to 10. Out of the 4453 participants in the main study, 3974 was included in the final analysis. Higher age, higher ESI, lower FEV1 and male sex increased hazard ratio of respiratory death. ESI was significantly correlated to respiratory death but not non-respiratory death, while high age, male sex and low FEV₁ was associated with non-respiratory as well as respiratory death. Current smoking habits increased the hazard of respiratory death but did not reach significance (p 0.066) One unit increase in ESI increased hazard rate of all-cause death by 20% (p 0.0002) and hazard ratio of respiratory death by 57% (p <0.0001). The ESI is a novel clinical marker of emphysema severity that has a predictive value of respiratory death at group level.

Note:
Funding Information: None to declare.

Declaration of Interests: None to declare.

Ethics Approval Statement: The study was approved by the regional ethics committee of Lund University (2002; registration number LU 744-00) and all participants or carers provided written consent.

Keywords: COPD emphysemaspirometrymortality