Burden of Illness of Sickle Cell Disease in Countries of the Middle East: A Systematic Literature Review

Background: Sickle cell disease (SCD) is a group of hereditary hemolytic disorders characterized by abnormal hemoglobin molecules that distort red blood cells (RBCs) into a rigid, sickle-like shape. The global burden of SCD is substantial. In North America and Europe, the incidence and prevalence of SCD range from approximately 0.00008% to 0.274% and 0.01% to 0.05%, respectively. In these regions, the median age at death for patients with the disease ranges from 40 to 60 years, and childhood mortality has steadily dropped in recent years. Sickle cell disease is more common in certain ethnic groups and is most prominent in malaria-endemic regions, as individuals who are heterozygous for the sickle cell mutation are relatively protected against malaria infection. One such region is the Middle East, where the incidence and prevalence rates of SCD in some countries are amongst the highest in the world, and childhood mortality rates for patients with SCD are relatively high. However, the overall burden of illness-encompassing various aspects of disease and their impact on costs and health outcomes-is largely uncharacterized for SCD in Middle Eastern countries. Understanding the burden of illness of SCD in this region could help to inform and prioritize health care policies and assist in the allocation of health care resources.

Objective: To understand the burden of illness of SCD in Middle Eastern countries by identifying available information using a systematic literature review (SLR).

Methods: A systematic literature search of English-language studies published within five years of the search date (July 2018) was conducted using PubMed and EMBASE databases. Pre-defined population, intervention, comparator, and outcomes (PICO) criteria were used to identify relevant studies conducted in Middle Eastern countries. All patient populations with SCD receiving any approved or guideline-recommended medical interventions were of interest. Studies that reported any outcomes related to burden of illness such as epidemiology, treatment patterns, prognosis, health-related quality of life (HRQoL), and economic information were included. All study types were included except for case reports and conference meeting minutes.

Results: Twenty-three studies from Middle Eastern countries met the inclusion criteria (Figure 1). Of these studies, eight were from Saudi Arabia, one was from the United Arab Emirates, six were from Bahrain, three were from Lebanon, one was from Oman, one was from Kuwait, and three were from Egypt. Epidemiological information was captured for six countries, treatment pattern information was captured for three countries, disease prognosis information was captured for six countries, HRQoL information was captured for two countries, and cost information was captured for one country.

Overall, the incidence and prevalence of SCD in Middle Eastern countries both ranged from approximately 0.04% to 2.1%. Vaso-occlusive crises (VOC), acute chest syndrome (ACS), acute splenic sequestration events, viral infections, and anemic/hemolytic events were the most common causes of hospitalization; however, the rates generally differed between countries. Limited information was available for disease prognosis; factors related to high mortality included age, frequency of hospitalizations, and length of stay in the ICU. Information on HRQoL was even further limited; only two studies captured by the search reported this type of data. In these two studies, SCD patients experienced a reduced QoL compared with non-diseased controls. The reported reductions in QoL for SCD patients were associated with poor education, age of onset of ACS and blood transfusion in the three-month period preceding the study, and specific physical symptoms including fever and pain. Finally, the only published economic information identified by the search was the cost of screening for SCD with high-performance liquid chromatography (HPLC) in Lebanon ($3.50 per newborn).

Conclusions: Substantial data gaps across all aspects of burden of illness were identified. Moreover, the data captured-especially for HRQoL and costs-were limited and reported in very few countries. These findings highlight the importance of further characterizing the burden of illness of SCD in the Middle East, where the incidence and prevalence rates of the disease are relatively high.

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