Asthma symptom severity and diagnosis in adolescents in sub-Saharan Africa

Abstract

Introduction: The prevalence of asthma in Africa has been rising. The International Study of Asthma and Allergies in Childhood (ISAAC) study has shown that symptom severity is higher in African adolescents compared to other global regions. Studies on asthma control and diagnosis, in African children, are limited. The objectives of the Achieving Control of Asthma in Children in Africa (ACACIA) study are to identify adolescents with asthma symptoms and collect data on asthma diagnosis and control in six African countries.

Methods: Data was collected from 12-14 year-old urban school children in Ghana, Malawi, Nigeria, South Africa, Uganda, and Zimbabwe. Study inclusion criteria were current asthma symptoms (wheeze in the last 12 months) and/or “asthma ever”. Those included completed a survey, spirometry, and exhaled nitric oxide (FeNO) testing. Objective markers of asthma were defined as either or a combination of i) an FEV1 < 80% of percent predicted and an FEV1/FVC ratio < the lower limit of normal, ii) bronchodilator reversibility (increase in FEV1 ≥ 12% and 200 ml), iii) raised FeNO (≥35 ppb).

Results: Of 442 children who screened positive, 65% (n=272) had ISAAC-defined severe symptoms. 73% of those with severe symptoms, had wheeze affecting speech and 50% had 4 or more attacks of wheeze within the last 12 months. Of the children with asthma symptoms, 72% (n=314) had no doctor-diagnosis of asthma. 62% (n=196) of these had ISAAC-defined severe symptoms and 32.7% had objective markers of asthma.

Conclusion: The high proportion of adolescents with severe asthma symptoms in Sub-Saharan Africa without an asthma diagnosis suggests the need for community-based asthma screening and subsequent medical input.