Either way, “to our best knowledge, this study is the first study to provide a comprehensive description of the epidemiology and global burden of CLL worldwide,” the authors reported in BioMedical Engineering Online.
The findings are an evaluation of data from the 2019 Global Burden of Disease study, which includes epidemiological data on 369 diseases in 204 nations and territories around the world.
According to the analysis, the age-standardized incidence rate of CLL rose globally over the last 3 decades, from 0.76 per 100,000 persons in 1990 to 1.34 per 100,000 in 2019, for an estimated annual percentage change of 1.86%.
While increases were observed across all economic levels, the highest increases were observed in regions with the highest social determinant index. Notably, the fastest rise was observed in middle-income regions.
“What cannot be ignored is the rapid growth of the disease burden in middle [social determinant index] regions, which potentially indicated an underestimated incidence and mortality in underdeveloped countries,” write the authors, led by senior author Huafeng Wang, MD, of the department of hematology, The First Affiliated Hospital, Zhejiang University, Hangzhou, China.
The highest annual age-standardized incidence rates in 2019 occurred in western Europe, high-income areas of North America and central Europe, while the fastest increase in the incidence of CLL occurred in east Asia, central Europe, and Andean Latin America, according to the study.
The age-standardized death rate from CLL also increased globally, from 0.40 per 100,000 persons in 1990 to 0.58 per 100,000 in 2019, for an estimated annual percentage change of 1.17.
The increases in death rates were observed across all income regions over the study period, with the highest age-standardized death rate in 2019, consistent with incidence rates, occurring in the highest-income regions, specifically in central Europe, western Europe, and high-income North America.
The geographic trends were similar in terms of disability-adjusted life-years, which increased globally from 9.20 per 100,000 persons in 1990 to 12.26 per 100,000 in 2019, for an estimated annual percentage change of 0.92%.
The authors noted that the geographic variation of CLL is consistent with research suggesting that White ancestry is a risk factor for this leukemia. And while the incidence of CLL is generally low in the 22 nations of the Arab League, the burden of disease is high in Israel.
Age and gender
The study shows that, during the past 30 years in general, CLL was more common among males, with some regional differences. For instance, in contrast to global trends, females in low-income regions accounted for the majority of incidence and mortality.
The majority of CLL cases occurred in people over the age of 50, which is consistent with known patterns of CLL occurring in older patients. Of note, the majority of cases between the ages of 50 and 69 were in low-income regions, while more than half of the incidence cases in higher-income regions were among those over the age of 70.