Epidemiology of Clinically Significant Forms of Alpha- and Beta Thalassemia: A Global Map of Evidence and Gaps
This systematic study looked at the worldwide and birth prevalence of clinically relevant types of alpha- and beta-thalassaemia. Searches were conducted in Embase, MEDLINE, and the Cochrane Library for observational studies published between January 1, 2000, and September 21, 2021.
Of the 2.093 unique records found, 69 studies described in 70 publications matched the qualifying requirements, including 6 records found through bibliographical searches.
Estimates of thalassaemia prevalence vary among nations and even within countries. Across 23 population-based studies reporting clinically significant alpha thalassaemia (e.g., haemoglobin H disease and haemoglobin Bart’s hydrops fetalis) and/or beta-thalassaemia (beta-thalassaemia intermedia, major, and/or haemoglobin E/beta-thalassaemia), prevalence estimates per 100 000 people ranged from 0.2 in Spain (2014-2017) to 27.2 in Greece (2010-2015) for combined beta- plus alpha-thalassaemia; from 0.03 in Spain (2014–2017) to 4.5 in Malaysia (2007–2018) for alpha-thalassaemia; and from 0.2 in Spain (2014–2017) to 35.7 to 49.6 in Iraq (2003–2018) for beta-thalassaemia.
Overall, the estimated prevalence of thalassaemia was greater in the Middle East, Asia, and the Mediterranean than in Europe or North America.
However, population-based prevalence figures for many countries were not discovered, and there was variation in case definitions, diagnostic methods, the type of thalassemia reported, and transfusion needs. There is a scarcity of population-based birth prevalence statistics. Twenty-seven studies from non-population-based samples revealed thalassaemia prevalence. Because such research tended to focus on extremely particular populations, the findings are unlikely to be nationwide generalizable.
Up-to-date, population-based epidemiological data for numerous nations are required to completely comprehend the global incidence of thalassaemia.
