Lung Volume Reduction Surgery: Reinterpreted With Longitudinal Data Analyses Methodology

The largest randomised controlled trial evaluating results of lung volume reduction surgery (LVRS) was conducted by the National Emphysema Treatment Trial (NETT) that published a series of reports for outcomes up to 24 months. However, patient outcomes were difficult to interpret due to limitations in and the presentation of conventional statistical analyses applied to longitudinal data. We reevaluated the NETT results using longitudinal data methodology to report longer-term outcomes to facilitate interpretation by clinicians and patients who are considering LVRS for emphysema management.

Trial data were released by the United States National Institutes of Health and the National Heart, Lung, and Blood Institute and analyzed using a mixed-effects model. Data on the difference in lung function variables between patients receiving LVRS vs medical care out to 5 years were estimated and are presented.

The 5-year differences in patients randomised to LVRS were a small but sustained improvement in lung function indicators of forced expiratory volume in 1 second, forced vital capacity, and residual volume of +1.4% (P < .001), +3.44% (P < .001) and -19.49% (P < .001) of the predicted values, respectively. With regards to physiological function, the 5-year difference in patients randomised to LVRS was an overall 0.89 W improvement in maximum workload (P = .069), -4.12 improvement in shortness of breath score (P < .001), and 0.088 improvement in quality of well-being score (P = .102).

Our results suggest that LVRS continues to have an important role in the treatment of patients with severe emphysema, with long-term benefits to lung function variables and a sustained improvement to the relief of dyspnea.