Rheumatic heart disease prevalence in Namibia: a retrospective review of surveillance registers.

Background: Rheumatic heart disease (RHD) is the most commonly acquired heart disease in children and young people in low and middle-income settings. Fragile health systems and scarcity of data persist to limit the understanding of the relative burden of this disease. The aims of this study were to estimate the prevalence of RHD and to assess the RHD-related health care systems in Namibia.

Methods: Data was retrieved from outpatient and inpatient registers for all patients diagnosed and treated for RHD between January 2010 to December 2020. We used descriptive statistics to estimate the prevalence of RHD. Key observations and engagement with local cardiac clinicians and patients helped to identify key areas of improvement in the systems.

Results: The outpatient register covered 0.032% of the adult Namibian population and combined with the cumulative incidence from the inpatient register we predict the prevalence of clinically diagnosed RHD to be between 0.05% and 0.10% in Namibia. Young people (< 18 years old) are most affected (72%), and most cases are from the north-eastern regions. Mitral heart valve impairment (58%) was the most common among patients. We identified weaknesses in care systems i.e., lack of patient unique identifiers, missing data, and clinic-based prevention activities.

Conclusion: The prevalence of RHD is expected to be lower than previously reported. It will be valuable to investigate latent RHD and patient follow-ups for better estimates of the true burden of disease. Surveillance systems needs improvements to enhance data quality. Plans for expansions of the clinic-based interventions must adopt the "Awareness Surveillance Advocacy Prevention" framework supported by relevant resolutions by the WHO.