{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T01:13:45Z","timestamp":1788830025343,"version":"build-2803163510"},"reference-count":26,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T00:00:00Z","timestamp":1767657600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Nutritional deficiency anemias\u2014including iron, vitamin B12, and folate deficiencies\u2014are common worldwide and are increasingly recognized as potential contributors to venous thromboembolism (VTE). Mechanistic and epidemiologic data suggest that anemia may promote thrombosis through hypoxia, endothelial activation, reactive thrombocytosis, and hyperhomocysteinemia. However, a focused synthesis of clinical and genetic evidence specifically linking nutritional deficiency anemia to VTE has been lacking. Methods: We conducted a systematic search of PubMed and the Cochrane Library from inception to 30 September 2025 to identify studies assessing nutritional deficiency anemia in relation to VTE outcomes. Eligible studies included observational designs, case reports, case series, and Mendelian randomization (MR) analyses. Quality assessment followed the Newcastle\u2013Ottawa Scale (NOS), Joanna Briggs Institute (JBI) checklists, and ROB-MR. The review was registered in PROSPERO (CRD420251235479). Results: Seven studies met the inclusion criteria. Observational analytical studies consistently showed that anemia was associated with adverse VTE-related outcomes. Lower hemoglobin predicted higher short-term mortality in acute pulmonary embolism (HR 1.16 per 1 g\/dL decrease), increased symptomatic VTE among hospitalized patients (RR 1.94), and greater long-term bleeding and mortality risk in VTE cohorts (HRs 1.41\u20132.89). Iron-deficiency anemia increased the odds of VTE in population-based data (OR 1.43), and case reports described unprovoked DVT in young adults with moderate to severe anemia. The MR study indicated a potential causal association between anemia traits and thrombosis at unusual anatomical sites (OR 1.446). No study demonstrated a significant association with recurrent VTE. Most analytical studies were rated as good\u2013high quality. Conclusion: Across multiple study designs, anemia\u2014particularly iron-deficiency anemia and low baseline hemoglobin\u2014appears to be an underrecognized factor associated with elevated VTE risk and adverse VTE-related outcomes. However, direct evidence for vitamin B12- and folate-deficiency anemia remains limited, and further well-designed prospective studies are required to confirm causality and clarify the contribution of specific nutritional deficiency subtypes, as well as to support integration of anemia assessment into VTE risk models.<\/jats:p>","DOI":"10.3390\/jcm15020411","type":"journal-article","created":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T09:40:29Z","timestamp":1767692429000},"page":"411","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Anemia as a Potent and Underrecognized Driver of Venous Thromboembolism: A Systematic Review"],"prefix":"10.3390","volume":"15","author":[{"given":"Ghaith K.","family":"Mansour","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Sciences, College of Pharmacy, Alfaisal University, Riyadh 11533, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-5180-1952","authenticated-orcid":false,"given":"Walaa A.","family":"Alshahrani","sequence":"additional","affiliation":[{"name":"King Abdullah International Medical Research Center (KAIMRC), Riyadh 11481, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1549-0941","authenticated-orcid":false,"given":"Lama","family":"Alfehaid","sequence":"additional","affiliation":[{"name":"King Abdullah International Medical Research Center (KAIMRC), Riyadh 11481, Saudi Arabia"},{"name":"Department of Pharmacy Practice, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, Riyadh 11481, Saudi Arabia"},{"name":"King Abdulaziz Medical City, National Guard Health Affairs, Riyadh 14611, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9104-5727","authenticated-orcid":false,"given":"Abdulmajeed M.","family":"Alshehri","sequence":"additional","affiliation":[{"name":"King Abdullah International Medical Research Center (KAIMRC), Riyadh 11481, Saudi Arabia"},{"name":"Department of Pharmacy Practice, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, Riyadh 11481, Saudi Arabia"},{"name":"King Abdulaziz Medical City, National Guard Health Affairs, Riyadh 14611, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2308-8407","authenticated-orcid":false,"given":"Majed S.","family":"Al Yami","sequence":"additional","affiliation":[{"name":"King Abdullah International Medical Research Center (KAIMRC), Riyadh 11481, Saudi Arabia"},{"name":"Department of Pharmacy Practice, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, Riyadh 11481, Saudi Arabia"},{"name":"King Abdulaziz Medical City, National Guard Health Affairs, Riyadh 14611, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/j.hoc.2015.11.002","article-title":"GBD 2013 Anemia Collaborators. 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