Spatial and Spatio-temporal Epidemiology 36 (2021) 100389 Contents lists available at ScienceDirect Spatial and Spatio-temporal Epidemiology journal homepage: www.elsevier.com/locate/sste Bayesian spatial modeling of transfusion-dependent β -thalassemia incidence rate in Fars Province, Southern Iran Sezaneh Haghpanah a,1 , Naeimehossadat Asmarian b,1,∗ , Omid Reza Zekavat a , Mohammadreza Bordbar a , Mehran Karimi a , Soheila Zareifar a , Mani Ramzi a , Sanaz Safaei a a Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran b Anesthesiology and Critical Care Research Center, Shiraz University of Medical Sciences, Shiraz, Iran a r t i c l e i n f o Article history: Received 23 May 2020 Revised 18 August 2020 Accepted 6 November 2020 Available online 7 November 2020 Keywords: β-thalassemia Anemia Transfusion Spatial Bayesian analysis Iran a b s t r a c t Background: Using maps and spatial analysis are technologies to evaluate the magnitude and spatial distribution of disease in epidemiology investigations. We aimed to conduct a Bayesian spatial analysis on epidemiologic data of transfusion-dependent β -thalassemia (TDT) patients. Methods: In this cross-sectional study, data of all TDT patients diagnosed during 1955–2018 in all coun- ties of Fars Province were obtained from data registry of the Organization of Special Diseases of Shiraz University of Medical Sciences in Shiraz, Fars Province, Iran. Besag, York, and Mollie’s (BYM) model was used for mapping. Results: The estimated relative risk ranged from 0.23 to 1.66 for TDT patients. The highest and lowest relative risks of TDT were observed in Larestan located in Southern and Abadeh in Northern Fars Province respectively. Conclusions: Determining the accurate geographical distribution of a chronic disease such as β -thalassemia can be an essential prerequisite in allocation of regional health system resources. © 2020 Published by Elsevier Ltd. Introduction β -thalassemia is one of the most common inherited single- gene disorders worldwide. It has the highest prevalence in the Mediterranean region, South-East Asia, the Indian subconti- nent, and the Middle East (Karimi et al., 2012). Nowadays, due to the migration of people, it has become a global problem (Colah et al.,2010; Vichinsky, 2005). Iran is one of the most affected countries and located on the thalassemia belt with a high fre- quency of β -thalassemia carriers (approximately 2–3 million) and about 25,000–26,000 patients with β -thalassemia major (Asadi- Pooya and Doroudchi, 2004; De Sanctis et al., 2017; Rezaee et al., 2012; Rezaei et al., 2015). β -thalassemia is caused by the decreased synthesis (β +) or absence (β o) of the β -globin chains, resulting in the imbalance between α- and β -globin chains leading to the precipitation and accumulation of excess unbound α-globin chains in erythroid precursors resulting in peripheral hemolysis as well ∗ Corresponding author. E-mail address: ns.asmarian@gmail.com (N. Asmarian). 1 Sezaneh Haghpanah and Naeimehossadat Asmarian have contributed equally to this work. as ineffective erythropoiesis. Depending on the amount of genetic defect, disease phenotype varies from mild to severe disease. Het- erozygotes form of β -thalassemia cause minor or carrier type of the disease with an estimated global prevalence of 1.5%. On the other hand, the homozygotes form of β -thalassemia may develop either β -thalassemia major or β -thalassemia inter- media. Patients with β -thalassemia major usually present with se- vere anemia in the first two years of life and need lifelong regular blood transfusions. Patients with β -thalassemia intermedia have milder anemia and less demand for blood transfusion, so they are diagnosed later. The treatment of the disease and management of its complications accounts for a considerable global disease burden (De Sanctis et al., 2017). In Iran, the highest prevalence of β -thalassemia has been de- tected in Northern and Southern Iran around the Caspian Sea and the Persian Gulf (Asadi-Pooya and Doroudchi, 2004). Consanguin- ity encountered as one of the essential responsible causes of the higher prevalence of the disease in these regions (Asadi-Pooya and Doroudchi, 2004). The mean annual cost per patient with thalassemia major was estimated as $ 8321.8 excluding the cost of lost welfare in Iran (Esmaeilzadeh et al., 2016) and $ 7464.4 in Taiwan (Ho et al., https://doi.org/10.1016/j.sste.2020.100389 1877-5845/© 2020 Published by Elsevier Ltd.