Diabetes mellitus and survival of non‐small cell lung cancer patients after surgery: A comprehensive systematic review and meta‐analysis

BACKGROUND: Diabetes mellitus (DM) is one of the most common comorbidities in surgically treated non‐small cell lung cancer (NSCLC) patients and has a negative impact on short‐term outcomes. However, the impact of DM on long‐term survival of such patients remains controversial; therefore, we conducted a comprehensive updated meta‐analysis. METHODS: We systematically searched relevant studies in PubMed, Embase, Cochrane Library, and Web of Science up to 6 September 2018. Hazard ratios (HRs) for the impact of DM on overall survival (OS) and recurrence‐free survival (RFS) of patients with surgically treated NSCLC were extracted and analyzed using the STATA 12.0 package. RESULTS: We included 13 cohort studies consisting of 4343 patients (730 patients with DM and 3613 patients without) with surgically treated NSCLC. Meta‐analysis showed that patients with DM had significantly poorer OS (random effects: HR 1.30, 95% confidence interval 1.05–1.60; P = 0.016) than those without. However, with a limited sample size, there was no significant difference in RFS (random effects: HR 1.06, 95% confidence interval 0.71–1.58; P = 0.786) between patients with and without DM after surgical resection of NSCLC. CONCLUSION: DM is an independent unfavorable prognostic factor for patients with surgically treated NSCLC. High‐quality studies with appropriate adjustment for confounding factors are needed to confirm our conclusions.