Non-communicable respiratory disease in Malawi: a systematic review and meta-analysis

Background Non-communicable respiratory diseases are important contributors to morbidity and mortality in sub-Saharan African countries such as Malawi. Aim To conduct a systematic review of the available literature relating to chronic respiratory disease in Malawi. Methods We conducted a systematic protocol-driven literature search of key scientific databases including Scopus and Medline. Papers were independently assessed for eligibility by two authors and included if they reported objective measures (including self-reported standard symptoms) of chronic respiratory disease and were conducted in Malawi. A meta-analysis of available estimates was then conducted. We re-analysed data from three of these studies in a secondary data analysis to allow for between-study comparisons. Results Our search identified 393 papers of which 17 (5 involving children and 12 involving adults) met the inclusion criteria. Wheeze was the symptom most frequently reported in children in the community (12.1%), hospital (11.2%) and HIV clinic (8.1%) settings. Cough was the symptom most frequently reported by adults in the community (3-18%). Spirometric abnormalities varied substantially between studies. For example, in adults, airflow obstruction varied between 2.3% and 20% and low forced vital capacity (FVC) varied between 2.7% and 52.8%. Conclusion We identified a high burden of chronic respiratory symptoms and abnormal spirometry (particularly low FVC) within paediatric and adult populations in Malawi. The estimates for country-wide burden related to this disease were limited by the heterogeneity of the methods used to assess symptoms and spirometry. There is an urgent need to develop a better understanding of the determinants and natural history of non-communicable respiratory disease across the life-course in Malawi.