Anemia in the general population: prevalence, clinical correlates and prognostic impact
- 1.2k Downloads
Low hemoglobin concentration is associated with increased mortality, but there is disagreement with regard to the clinical definition of anemia. We aimed to evaluate the prevalence, clinical correlates and association with total and cause-specific long-term mortality across the hemoglobin distribution and for previously proposed definitions of anemia. Blood hemoglobin concentration and mean corpuscular volume was measured in participants of the Malmö diet and cancer study—a prospective cohort study, and related to baseline characteristics and outcomes during follow-up. Primary endpoints were all-cause mortality, cardiovascular mortality and cancer-related mortality. A U-shaped association of hemoglobin with total mortality was observed in spline regression analyses, with nadir at hemoglobin 150 g/L among men and 130 g/L among women. Mortality increased steeply with more strict definitions of anemia, hazard ratio: 1.36, 1.94 and 2.16 for hemoglobin <140/130 (men/women), 132/122 and 130/120 g/L, respectively. Similar trends were seen for both cancer- and cardiovascular mortality. The incidence of coronary disease and cancer did not differ across groups. Erythrocyte volume was an independent predictor of mortality, with the highest mortality observed for macrocytic anemia, which was less prevalent than microcytic and normocytic anemia. Dietary intake of iron and vitamin B12 were significantly lower and use of antithrombotic medications was significantly higher in subjects with anemia. The World Health Organisation definition of anemia was associated with increased mortality (hazard ratio 2.16) but excess mortality was also observed at higher hemoglobin levels. Of morphological subtypes, anemia with macrocytosis was rare but associated with the highest mortality.
KeywordsAnemia Epidemiology Mean-corpuscular volume Hemoglobin
The Malmö Diet and Cancer study was made possible by grants from the Swedish Cancer Society, the Swedish Medical Research Council, the Swedish Dairy Association, the Albert Påhlsson and Gunnar Nilsson Foundations and the Malmö city council. J.G.S. was supported by the Swedish Heart–Lung Foundation, governmental funding of clinical research within the Swedish National Health Service, the Ulla Ekdahl foundation, the Thorsten Westerström foundation and Skåne University Hospital in Lund.
Conflict of interest
The authors declare no competing interests. All individuals provided written, informed consent. The regional ethics committee approved of the study.
- 8.Winther SA, Finer N, Sharma AM, Torp-Pedersen C, Andersson C. Association of anemia with the risk of cardiovascular adverse events in overweight/obese patients. Int J Obes (Lond). Prepublished on Jun 18 2013. doi: 10.1038/ijo.2013.111.
- 9.World Health Organisation. Hemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Geneva: World Health Organization; 2011.Google Scholar
- 10.World Health Organisation. Nutritional anaemias. Report of a WHO Scientific Group. Geneva: World Health Organisation; 1968.Google Scholar
- 23.Dödsorsakstatistik—Historik, metoder och tillförlitlighet. Socialstyrelsen. http://www.socialstyrelsen.se/Lists/Artikelkatalog/Attachments/18019/2010-4-33.pdf (14 May 2014).
- 25.Kvalitet och innehåll i patientregistret: Utskrivningar från 1964–2007 och besök i specialiserad öppenvård (exklusive primärvårdsbesök) 1997-2007. Socialstyrelsen. http://www.socialstyrelsen.se/Lists/Artikelkatalog/Attachments/8306/2009-125-15_200912515_rev2.pdf (14 May 2014).
- 32.Silverberg DS, Wexler D, Blum M, et al. The use of subcutaneous erythropoietin and intravenous iron for the treatment of the anemia of severe, resistant congestive heart failure improves cardiac and renal function and functional cardiac class, and markedly reduces hospitalizations. J Am Coll Cardiol. 2000;35(7):1737–44.PubMedCrossRefGoogle Scholar
- 34.Goddard AF, James MW, McIntyre AS, Scott BB. Guidelines for the management of iron deficiency anaemia. Gut. 2000;46(Suppl IV):iv1–iv5.Google Scholar