PURPOSE: Six-minute walk test is a useful tool to predict poor outcomes in patients with different types of advanced lung diseases. Classically, more value is given to the distance walked than other recoded variables. The objective of the study was to correlate variables obtained during 6-min walk test with mortality in patients with advanced lung disease who underwent evaluation for lung transplantation.
METHODS: We retrospectively reviewed the records of charts of 180 patients who underwent lung transplant evaluation at University of Florida between March 2001 and November 2008.
RESULTS: Six-min walk test was done on 3.5 ± 3.7 l/m of O2. The distance walked in 6 minutes was 261 ± 123 m (44 ± 21 % of predicted). The SpO2 dropped 6.8 ± 5.6 % and heart rate increased 21 ± 13 bpm during the test. Survival from the time of evaluation (censored for transplantation) was 89% and 59% at one and five years, respectively. The distance walked in meters and % of predicted inversely correlated with mortality (HR: 0.995 (0.992-0.998) and 0.97 (0.95-0.99), respectively). Patients who walked less than 200 meters (HR: 2.1 (1.1-4)) or < 45% of predicted (HR: 2.7 (1.2-5.7)) had higher mortality. The number of l/m of O2 during the test had a direct correlation with mortality (HR: 1.1 (1.02-1.2)). The difference in heart rate or SpO2 before and at the end of exercise did not correlate with mortality. In multivariate analysis only the number of l/m of O2 predicted mortality (HR: 1.1 (1.01-1.2)).
CONCLUSION: Number of l/m of O2 during the test and distance walk in meters or percentage of predicted correlated with mortality, however only the number of l/m of O2 remained significant in multivariate analysis.
CLINICAL IMPLICATIONS: Increased oxygen supplementation in l/m as well as a walking distance of less than 200 meters during the 6 minute walk test are predictive factors for mortality in advanced lung disease.
DISCLOSURE: Irina Timofte, No Financial Disclosure Information; No Product/Research Disclosure Information