D. C. Thomas1, B. N. Arnold1, M. DeLuzio1, F. C. Detterbeck1, D. J. Boffa1, J. D. Blasberg1, A. W. Kim2 1Yale School Of Medicine,Section Of Thoracic Surgery,New Haven, CT, USA 2University Of Southern California,Division Of Thoracic Surgery,Los Angeles, CA, USA
Introduction: Patients with poor pulmonary function tests (PFTs) and more comorbid conditions, identified by the Charlson comorbidity index (CCI), have been associated independently with an increased risk of perioperative complications after lung cancer surgery. Many large national databases currently available lack PFT data and consequently often rely on surrogates such as comorbidity indices. This study sought to evaluate the interaction of PFTs and comorbidities on postoperative complications in a large single institution dataset of patients undergoing lobectomy for lung cancer.
Methods: Patients undergoing lobectomy for lung cancer at an academic medical center from 2008-14 were examined. Patients were stratified by predicted postoperative FEV1 and DLCO:1) low PFTs (either FEV1 or DLCO ≤40%),2) moderate PFTs (both >40%, but not >80%), and 3) high PFTs (both ≥80%). The primary outcome was incidence of any complication in the postoperative period. Variables were analyzed using the χ2 test and predictors of complications using a multivariate model.
Results: A total of 376 patients were identified as having undergone lobectomy for lung cancer. Low ppoPFTs comprised 9% (34) of patients, while 76% (286) had moderate ppoPFTs, and 15% (56) had high ppoPFTs. Forty-one percent (154) of patients had a CCI=0, 32% (121) had CCI=1, and 27% (101) had a CCI≥2. The overall incidence of complications was 36% (136). Bivariate analysis demonstrated that among patients with high ppoPFFTs and moderate ppoPFTs, as CCI increased from 0 to 1 to ≥2, the incidence of complications increased then plateaued (Figure 1). However, in patients with low ppoPFTs, increasing CCI from 0 to 1 to ≥2 continued to increase the incidence of complications. On multivariable, low and moderate ppoPFTs independently predicted complications compared to patients with high ppoPFTs (OR=5.4, P<0.001 and OR=2.2, P=0.05, respectively), while CCI was not independently predictive.
Conclusion: Poor PFTs remain an independent predictor of complications after lobectomy for lung cancer and this finding alone supports utilization of PFTs in the analysis of outcomes. However, poor PFTs appear to have a greater negative impact when the number of comorbidities increases. This effect is distinctly different and not observed among patients with superior PFTs. Therefore, while the absence of PFT data may not be as impactful when the comorbidities are minimal, the impact of absent PFT data may be more profound when their values are poor and found in patients with a greater number of comorbidities.
