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. 2008 Jul;8(7):1498-505.
doi: 10.1111/j.1600-6143.2008.02264.x.

Baseline 6-min walk distance predicts survival in lung transplant candidates

T Martinu  1 , M A Babyak, C F O'Connell, R M Carney, E P Trulock, R D Davis, J A Blumenthal, S M Palmer; INSPIRE Investigators
Affiliations

Baseline 6-min walk distance predicts survival in lung transplant candidates

T Martinu et al. Am J Transplant. 2008 Jul.

Abstract

In a large, prospectively followed, two-center cohort of patients listed for lung transplantation (n = 376), we used Cox proportional hazards models to determine the importance of baseline 6-min walk distance (6MWD) in predicting patient survival. 6MWD used as a continuous variable was a significant predictor of survival after adjusting for other important covariates when transplant was considered as a time-varying covariate (HR for each 500 ft increase in 6MWD = 0.57, 95% CI: 0.43-0.77, p = 0.0002). 6MWD remained an important predictor of survival in models that considered only survival to transplant (HR for each 500 ft increase in 6MWD = 0.41, 95% CI: 0.27-0.62, p < 0.0001) or survival only after transplant (HR for each 500 ft increase in 6MWD = 0.40, 95% CI: 0.22-0.72, p = 0.002). Unadjusted Kaplan-Meier analysis demonstrates significantly different survival by 6MWD tertiles (<900, 900-1200, or >1200 ft, p-value = 0.0001). In the overall model, 6MWD prediction of survival was relatively homogeneous across disease category (6MWD by disease interaction term, p-value = 0.63). Our results demonstrate a significant relationship between baseline 6MWD and survival among patients listed for lung transplantation that exists across all native disease categories and extends through transplantation. The 6MWD is thus a useful measure of both urgency and utility among patients awaiting lung transplantation.

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Figures

Figure 1
Figure 1. Unadjusted Kaplan-Meier survival estimates by tertile of 6 MWD
Log rank test for difference among tertile groups, p = 0.0001. Values at bottom of figure represent number at risk for each tertile group
Figure 2
Figure 2. Relation of 6MWD and predicted probability of survival 3 years after study entry adjusted for age, native disease, and FEV1
Dashed lines represent 95% confidence limits. Tick marks on top axis represent case density for the 6MWD.
See this image and copyright information in PMC

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