en Cardiology Cardiology Review Article Review Article <span style="font-size:14px;"><span style="font-family:times new roman;"><span style="color:#0000FF;"><strong><em>Background:</em></strong></span> Cardiovascular disease (CVD) is the first cause of mortality worldwide, with all the healthcare systems facing this very challenging issue. Aspirin continues to be the major gold-standard treatment worldwide in the prevention of thrombotic disease in patients with CVD, even though not all individuals respond to antiplatelet therapy in a similar way, being resistant to aspirin. The aim of this study was to determine the prevalence of laboratory defined aspirin resistance in CVD patients worldwide.<br> <span style="color:#0000FF;"><em><strong>Methods: </strong></em></span>Relevant articles were identified through searching EMBASE, PubMed/ MEDLINE, ISI /Web of Science, Scopus, and the Cochrane Library, from January 2000 to February 2018. The methodological quality of the included studies was critically appraised using the Newcastle-Ottawa scale. The pooled prevalence of laboratory defined aspirin resistance was computed using the Der Simonian-Laird random-effect model.<br> <span style="color:#0000FF;"><strong><em>Results:</em></strong></span> We included 65 studies, with a total of 10,729 patients. The overall prevalence of laboratory defined aspirin resistance in CVD patients was 24.7% ([95%CI 21.4-28.4]. Women were found to be at increased risk of laboratory defined aspirin resistance compared to men, with an odds ratio of 1.16 [95%CI 0.87-1.54].&nbsp;<br> <span style="color:#0000FF;"><strong><em>Conclusion: </em></strong></span>Doctors and healthcare providers should pay special attention to aspirin resistance since lack of awareness could cause problems and increase mortality in these patients, if not properly treated with higher aspirin doses.</span></span> Prevalence, Aspirin resistance, cardiovascular disease, systematic review, meta-analysis 124 134 http://caspjim.com/browse.php?a_code=A-10-1322-1&slc_lang=en&sid=1 Parvin Ebrahimi ebrahimi@gmail.com 100319475328460021713 100319475328460021713 No Department of Health Services Management, School of Health Management and Information Sciences, Iran University of Medical Sciences, Tehran, Iran. Zeynab Farhadi farhadi_zeynab@yahoo.com 100319475328460021714 100319475328460021714 Yes Department of Health Services Management, School of Health Management and Information Sciences, Iran University of Medical Sciences, Tehran, Iran Masoud Bahzadifar behzadifar@gmail.com 100319475328460021715 100319475328460021715 No Social Determinants of Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran Hosein Shabaninejad shaabani@gmail.com 100319475328460021716 100319475328460021716 No School of Health Management and Information Sciences of Iran University of Medical Sciences (IUMS), and 7. Health Economic Group, Institute of Health & Society, Newcastle University, UK Hasan abolghasem gorji gorji@gmail.com 100319475328460021717 100319475328460021717 No School of Health Management and Information Sciences of Iran University of Medical Sciences (IUMS), Masood Tahermi mirghaed taheri@gmail.com 100319475328460021718 100319475328460021718 No School of Health Management and Information Sciences of Iran University of Medical Sciences (IUMS), Morteza Salemi salemi@gmail.com 100319475328460021719 100319475328460021719 No School of Health Management and Information Sciences of Iran University of Medical Sciences (IUMS), Kamyar Amin kamyar@gmail.com 100319475328460021720 100319475328460021720 No School of Medical Sciences, Babol University of Medical Sciences, Babol, Iran Roghayeh Mohammadibakhsh mohamadi@gmail.com 100319475328460021721 100319475328460021721 No School of Health Management and Information Sciences of Iran University of Medical Sciences (IUMS), Nicola Luigi Bragazzi nicola@gmail.com 100319475328460021722 100319475328460021722 No School of Public Health, Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy Rahim Sohrabi sohrabi@gmail.com 100319475328460021723 100319475328460021723 No Iranian Social Security Organization, Zanjan Province Health Administration, Zanjan, Iran