Background: Because of the assumed beneficial effect of lung transplantation on survival, controlled trials to assess the therapeutic benefit of lung transplantation are considered to be unethical. Therefore other methods must be used to provide control data. In this study the effect of lung transplantation on survival for patients with end-stage pulmonary disease was analyzed, with waiting list survival rates used as control data.
Methods: The analysis was based on 157 consecutive patients who were put on the waiting list of the Dutch lung transplantation program during the period November 1990 to January 31, 1996, of whom 76 underwent transplantation. Following the principles of control group estimation as set out in the context of heart transplantation, a stepwise approach was used to arrive at a multivariate time-dependent Cox regression model. The following prognostic variables were included in the analyses: age, forced expiratory volume in 1 second, partial pressure of carbon dioxide, partial pressure of oxygen, and diagnosis.
Results: The 1- and 2-year waiting list survival rates were 78% and 58%, respectively. The 1- and 2-year transplantation survival rates (i.e., survival from placement on the waiting list, including posttransplantation survival) were 79% and 64%, respectively. The multivariate time-dependent Cox analysis showed that lung transplantation reduced the risk of dying by 55% (95% confidence interval, 3% to 79%). For patients with emphysema the risk of dying was estimated to be 77% lower than for patients with other diagnoses (96% confidence interval, 50% to 89%).
Conclusions: With Cox regression, adjusting for age, forced expiratory volume in 1 second, partial pressure of carbon dioxide, partial pressure of oxygen, and diagnosis, lung transplantation showed a statistically significant effect on survival in selected patients with end-stage pulmonary disease.