Statins use and the risk of all and subtype hematological malignancies: a meta-analysis of observational studies

In order to quantify the association between use of statins and the risk of all hematological malignancies and of subtypes, we performed a meta-analysis of observational studies. We achieved a MEDLINE/EMBASE comprehensive search for studies published up to August 2014 investigating the association between use of statins and the risk of hematological malignancies, including Hodgkin- and non-Hodgkin lymphoma, leukemia, and myeloma. Fixed- and random-effect models were fitted to estimate the summary relative risk (RR) based on adjusted study-specific results. Between-study heterogeneity was assessed using the Q and I-2 statistics and the sources of heterogeneity were investigated using Deeks' test. Moreover, an influence analysis was performed. Finally, publication bias was evaluated using funnel plot and Egger's regression asymmetry test. Fourteen studies (10 case-control and four cohort studies) contributed to the analysis. Statin use, compared to nonuse of statins, was negatively associated with all hematological malignancies taken together (summary RR 0.86; 95% CI: 0.77-0.96), with leukemia (0.83; 0.74-0.92), and non-Hodgkin lymphoma (0.81; 0.68 to 0.96), but it was not related to the risk of myeloma (0.89; 0.53-1.51). Long-term users of statins showed a statistically significant reduction in the risk of all hematological malignancies taken together (0.78; 0.71-0.87). Statistically significant between-studies heterogeneity was observed for all outcome except for leukemia. Heterogeneity was caused by differences confounding-adjustment level of the included studies only for Myeloma. No significant evidence of publication bias was found.