Asthma and atopy in Angola: a cluster analysis

<bold>Background:</bold> Asthma is a complex and heterogeneous disease, with several phenotypes described but not yet clearly defined, especially in low- and middle-income countries. However, phenotypic characteristics are important for better management of the disease. <bold>Objectives:</bold> Identify clinical clusters in Angolan asthmatics. <bold>Methods:</bold> A cross-sectional study was carried out with asthmatic patients aged 18 and over, followed up at a pulmonology outpatient clinic in Luanda, the capital city of Angola. We used questionnaires with questions related to asthma control and allergic rhinitis symptoms, personal and family history of asthma and allergies, drugs used, and sociodemographic and environmental questions. Atopy was defined by positive skin prick tests. Respiratory function was assessed by spirometry. The data was analyzed using SPSS v25. A cluster analysis was carried out using the Two-Step method (first non-hierarchical and second hierarchical). <bold>Results:</bold> The sample consisted of 305 asthmatics with a mean age of 41.3±15.5 years, most of them women. Around 56% of the patients had asthma associated with allergic rhinitis, 26% had a history of allergic disease in childhood, 57% had a family history of asthma, 67% were sensitized to any aeroallergens tested, and 77% were polysensitized (most common were mites and fungi). We identified three clusters. The first (42%) included men with mild, predominantly non-allergic asthma. The second (26%) included women with mild asthma, but predominantly allergic. The third (32%) included women with moderate to severe asthma, but predominantly non-allergic. <bold>Conclusion:</bold> Cluster analysis showed that non-allergic asthma predominated among Angolan adult asthmatics. Further studies are needed to clarify these aspects.