Prevalence of allergic diseases and evaluation of total IgE and blood eosinophils as diagnostic biomarkers in Colombia, a tropical country

Abstract Introduction The prevalence of allergic conditions and inflammatory T2 diseases has been widely studied in developed countries but less explored in developing countries located in the tropics. Total IgE (tIgE) and blood eosinophils count (BEC) are frequently used for assessing type 2 (T2) inflammation. However, their diagnostic performance information is limited in populations where different non-allergic factors could affect the interpretation of these biomarkers. Objective To determine the prevalence of asthma, rhinitis, conjunctivitis, rhinosinusitis, and atopic dermatitis, in Colombian population over 18 years old and to evaluate the diagnostic performance of tIgE and BEC. Methods Cross-sectional national-based study in 6 Colombian cities. The diagnostic performance of the cut-off points for tIgE (100 IU/mL) and BEC (150 cells/uL) suggested by some international guidelines was evaluated with a comparison of allergic group versus non-allergic group. Results A total of 4248 individuals participated; 1465 (34.4%) had an allergic condition (asthma 13.5%, rhinitis 32.2%, rhinosinusitis 6.3%, conjunctivitis 25.9%, and atopic dermatitis 7.2%). For tIgE, 40.7% of the non-allergic group and 85.9% of the allergic group were over 100 IU/mL (Sensitivity 86%, specificity 59%). For BEC, 43.9% in the non-allergic group and 79.9% in the allergic group were over 150 cells/uL (Sensitivity 79%, specificity 56%). Conclusion Allergic conditions affect around 30% of the population in Colombia with some differences according with the prevalence of each disease between cities. The cut-off points used traditionally for tIgE and BEC had moderate diagnostic performance to detect allergic diseases in tropical population.