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

Abstract

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.