title: Anti-diabetic medications do not influence risk of lung cancer in patients with diabetes mellitus: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Several preclinical and observational studies have shown that anti-diabetic medications (ADMs) may modify the risk of lung cancer. We performed a systematic review and meta-analysis evaluating the effect of metformin, sulfonylureas (SUs), thiazolidinediones (TZDs), and insulin on the risk of lung cancer in patients with diabetes mellitus (DM).
  
  
  METHODS
  We conducted a systematic search of Pubmed and Web of Science, up to August 20, 2013. We also searched the Conference Proceedings Citation Index (CPCI) and China National Knowledge Infrastructure (CNKI) for abstracts from major meetings. Fixed or random effect pooled measures were selected based on heterogeneity among studies, which was evaluated using Q test and the I2 of Higgins and Thompson. Meta-regression was used to explore the sources of between-study heterogeneity. Publication bias was analyzed by Begg's funnel plot and Egger's regression test. Associations were assessed by odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  A total of 15 studies (11 cohort, 4 case-control) were included in this meta-analysis. In observational studies no significant association between metformin (n=11 studies; adjusted OR=0.99, 95%CI: 0.87-1.12), SUs (n=5 studies; adjusted OR=0.98, 95%CI: 0.79-1.22), or TZDs (n=7 studies; adjusted OR=0.92, 95%CI: 0.75-1.13), insulin (n=6 studies; adjusted OR=1.13, 95%CI: 0.79-1.62) use and risk of developing lung cancer was noted. There was considerable inherent heterogeneity between studies not explained by study design, setting, or location.
  
  
  CONCLUSIONS
  Meta-analysis of existing studies does not support a protective or harmful association between ADMs use and risk of lung cancer in patients with DM. There was considerable heterogeneity across studies, and future, well-designed, prospective studies would be required for better understanding of any association.
authors.affiliation: Clinical Epidemiology Unit, Qilu Hospital of Shandong University, Jinan, China E-mail : lvming@sdu.edu.cn.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Nie
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Mao-Qiang
authors.initials: MQ
authors.lastname: Zhuang
authors.forename: Ming
authors.initials: M
authors.lastname: Lu
mesh_terms: D003920:Diabetes Mellitus / Q000188:drug therapy*; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects* / Q000627:therapeutic use*; D007328:Insulin / Q000009:adverse effects / Q000627:therapeutic use; D008175:Lung Neoplasms / Q000453:epidemiology*; D008687:Metformin / Q000009:adverse effects / Q000627:therapeutic use; D013453:Sulfonylurea Compounds / Q000009:adverse effects / Q000627:therapeutic use; D045162:Thiazolidinediones / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D013453:Sulfonylurea Compounds; D045162:Thiazolidinediones; D008687:Metformin