Following the stepwise approach to the rank ordering of interventions on the basis of their cost effectiveness, we first report the average cost effectiveness ratios of all interventions within each disease area (appendix table B1 on bmj.com).
Second, we report the incremental cost effectiveness ratios for those interventions that both cost less and provide more health effects than other interventions, and these indicate the economic attractiveness of interventions within each disease area (same table).
In trachoma control, trichiasis surgery is the most cost effective intervention, followed by mass treatment with azithromycin in both regions. Both mass treatment with tetracycline ointment and targeted treatment with azithromycin are not cost effective. In cataract control, extracapsular cataract surgery dominates intracapsular surgery in both regions. In both regions, passive screening of children and adults for hearing disorders (in combination with provision of hearing aids) is most cost effective, followed by screening of adults every five years and annual screening of primary and secondary school children. Screening of adults every 10 years is not cost effective. For treatment of chronic otitis media, treatment with topical antibiotics is the most cost effective intervention in both regions. For screening for refractive error (including the provision of spectacles), screening of all primary and secondary school children is most cost effective in sub-Saharan Africa. In South East Asia, screening of secondary school children is most cost effective, followed by screening of both primary and secondary school children.
In a third step, we rank interventions according to their incremental cost effectiveness ratio across all disease areas (tables 4 and 5 for sub-Saharan Africa and South East Asia). This is illustrated in the figure for sub-Saharan Africa. Implementation of all cost effective interventions would cost around $Int19 per capita in sub-Saharan Africa.
Table 4 Cost effectiveness of strategies to combat vision and hearing loss in WHO sub-Saharan African sub-region AfrE
Table 5 Cost effectiveness of strategies to combat vision and hearing loss in WHO South East Asian sub-region SearD
Incremental cost effectiveness ratios and cumulative cost per capita ($Int) of interventions to combat vision and hearing loss in WHO sub-Saharan African sub-region AfrE. Cost per DALY averted (bars) ranges from very cost effective (such as treatment (more ...)
In both regions treatment of chronic otitis media with topical antibiotics is the most cost effective intervention, with an average cost per DALY averted of <$Int63 at all levels. In sub-Saharan Africa the next most cost effective interventions are trichiasis surgery, extracapsular cataract surgery, annual screening of all primary and secondary school children for refractive error, and treatment for meningitis with ceftriaxione. In South East Asia the next most cost effective interventions are treatment of meningitis with ceftriaxione, extracapsular cataract surgery, screening of all primary and secondary school children for refractive error, and trichiasis surgery. In both regions these interventions all cost <$Int285 per DALY averted (incremental cost effectiveness ratio, with the exact order of interventions dependent on coverage level). In both regions introducing screening for hearing impairment in combination with the delivery of hearing aids, at 80% coverage level costs around $Int1000 per DALY averted. According to WHO-CHOICE benchmark on cost effectiveness, these interventions can all be considered very cost effective. Mass treatment with azithromycin is the least cost effective intervention in both regions but can, depending on the coverage level, still be considered cost effective in the sub-Saharan African region. In the absence of any budgetary constraint implementation of all interventions would lead to a total health gain of up to 32 million DALYs in sub-Saharan Africa and 84 million DALYs in South East Asia.
The probabilistic uncertainty analysis depicted in appendix C on bmj.com shows the impact of plausible variations in total costs and total effects and shows that the average cost effectiveness ratios of most interventions would retain their classification of highly cost effective or cost effective after taking into account such uncertainty. A similar logic would apply to the incremental cost effectiveness ratio.