500 Meters Is a Result of 6-Minute Walk Test Which Differentiates Patients with High and Low Risk of Postoperative Complications after Lobectomy-A Validation Study.

The 6-min walk test (6MWT) is a simple method of identifying patients with a high risk of postoperative complications. In this study, we internally validated the previously obtained threshold value of 500 m in the 6MWT as differentiating populations with a high and a low risk of postoperative complications after a lobectomy. Between November 2011 and November 2016, 624 patients who underwent a lobectomy and performed the 6MWT preoperatively entered this study. We compared the complication rates of two groups of patients-those who walked more than and those who walked less than 500 m. The patients who did not reach the distance of 500 m in the 6MWT were older (70 vs. 63 years p < 0.001), had worse pulmonary function tests (FEV1% 84 vs. 88 p = 0.041) and had a higher Charlson Comorbidity Index (p < 0.001). The patients who had a worse result in the 6MWT had a higher complication rate (52% vs. 42% p = 0.019; OR: 1.501 95% CI: 1.066-2.114) and a longer median postoperative hospital stay (7 vs. 6 days p = 0.010). In a multivariate analysis, the result of the 6MWT and pack-years proved to independently influence the risk of postoperative complications. This internal validation study confirms that 500 m is a result of the 6MWT which differentiates patients with a higher risk of postoperative complications and a prolonged hospital stay after a lobectomy.