The epidemiology of haemolytic anaemia varies with underlying cause. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked defect in enzyme metabolism causing haemolysis after illness or certain drugs, is the most common deficiency of erythrocyte enzymes that results in a shortening of the erythrocyte lifespan. An estimated 360 to 400 million people are affected worldwide.[3]Nkhoma ET, Poole C, Vannappagari V, et al. The global prevalence of glucose-6-phosphate dehydrogenase deficiency: a systematic review and meta-analysis. Blood Cells Mol Dis. 2009 May-Jun;42(3):267-78.
https://www.doi.org/10.1016/j.bcmd.2008.12.005
http://www.ncbi.nlm.nih.gov/pubmed/19233695?tool=bestpractice.com
[4]Lippi G, Mattiuzzi C. Updated worldwide epidemiology of inherited erythrocyte disorders. Acta Haematol. 2020;143(3):196-203.
http://www.ncbi.nlm.nih.gov/pubmed/31550707?tool=bestpractice.com
Prevalence of G6PD deficiency ranges from 50% in Kurdish Jews to <1:1000 in northern Europeans.[5]Beutler E. Red cell enzyme defects. Hematol Pathol. 1990;4(3):103-14.
http://www.ncbi.nlm.nih.gov/pubmed/2258359?tool=bestpractice.com
It is found in Chinese and Southeast Asian populations, but is rare in Japan. Africa is the World Health Organization region with the highest incidence of G6PD deficiency; it is very common in the sub-Saharan region.[3]Nkhoma ET, Poole C, Vannappagari V, et al. The global prevalence of glucose-6-phosphate dehydrogenase deficiency: a systematic review and meta-analysis. Blood Cells Mol Dis. 2009 May-Jun;42(3):267-78.
https://www.doi.org/10.1016/j.bcmd.2008.12.005
http://www.ncbi.nlm.nih.gov/pubmed/19233695?tool=bestpractice.com
[4]Lippi G, Mattiuzzi C. Updated worldwide epidemiology of inherited erythrocyte disorders. Acta Haematol. 2020;143(3):196-203.
http://www.ncbi.nlm.nih.gov/pubmed/31550707?tool=bestpractice.com
Prevalence of G6PD deficiency among black males is 11%.[6]Heller P, Best WR, Nelson RB, et al. Clinical implications of sickle-cell trait and glucose-6-phosphate dehydrogenase deficiency in hospitalized black male patients. N Engl J Med. 1979 May 3;300(18):1001-5.
http://www.ncbi.nlm.nih.gov/pubmed/431593?tool=bestpractice.com
It occurs in <10% of black females, and in lower frequencies in people from the Mediterranean basin.[7]Prchal JT, Gregg XT. Red cell enzymes. Hematology Am Soc Hematol Educ Program. 2005 Jan 1;1:19-23.
http://asheducationbook.hematologylibrary.org/cgi/content/full/2005/1/19
http://www.ncbi.nlm.nih.gov/pubmed/16304354?tool=bestpractice.com
Warm antibody haemolytic anaemia is the most common form of autoimmune haemolytic anaemia, and affects more women than men.[8]Barcellini W, Fattizzo B. How I treat warm autoimmune hemolytic anemia. Blood. 2021 Mar 11;137(10):1283-94.
https://ashpublications.org/blood/article/137/10/1283/475030/How-I-treat-warm-autoimmune-hemolytic-anemia
http://www.ncbi.nlm.nih.gov/pubmed/33512406?tool=bestpractice.com
[9]Tranekær S, Hansen DL, Frederiksen H. Epidemiology of secondary warm autoimmune haemolytic anaemia: a systematic review and meta-analysis. J Clin Med. 2021 Mar 17;10(6):1244.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002719
http://www.ncbi.nlm.nih.gov/pubmed/33802848?tool=bestpractice.com
It may arise spontaneously or in association with diseases such as systemic lupus erythematosus, lymphoma, or chronic lymphocytic leukaemia.[8]Barcellini W, Fattizzo B. How I treat warm autoimmune hemolytic anemia. Blood. 2021 Mar 11;137(10):1283-94.
https://ashpublications.org/blood/article/137/10/1283/475030/How-I-treat-warm-autoimmune-hemolytic-anemia
http://www.ncbi.nlm.nih.gov/pubmed/33512406?tool=bestpractice.com
[10]Go RS, Winters JL, Kay NE. How I treat autoimmune hemolytic anemia. Blood. 2017 Jun 1;129(22):2971-9
http://www.ncbi.nlm.nih.gov/pubmed/28360039?tool=bestpractice.com
[11]Kalfa TA. Warm antibody autoimmune hemolytic anemia. Hematology Am Soc Hematol Educ Program. 2016 Dec 2;2016(1):690-7.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6142448
http://www.ncbi.nlm.nih.gov/pubmed/27913548?tool=bestpractice.com
Drugs are a rare but well-described cause of haemolytic anaemia, estimated to occur in 1 in 1 million of the population.[8]Barcellini W, Fattizzo B. How I treat warm autoimmune hemolytic anemia. Blood. 2021 Mar 11;137(10):1283-94.
https://ashpublications.org/blood/article/137/10/1283/475030/How-I-treat-warm-autoimmune-hemolytic-anemia
http://www.ncbi.nlm.nih.gov/pubmed/33512406?tool=bestpractice.com
[12]Garratty G. Drug-induced immune hemolytic anemia. Hematology Am Soc Hematol Educ Program. 2009 Jan 1;1:73-9.
https://asheducationbook.hematologylibrary.org/cgi/content/full/2009/1/73
http://www.ncbi.nlm.nih.gov/pubmed/20008184?tool=bestpractice.com