Consideration of health inequity in systematic reviews and primary studies on risk factors for hearing loss

Background

Health inequities are systematic, avoidable, and unfair differences in health between populations or population subgroups. There is increased recognition of the need for systematic reviews (SRs) to address health inequities, including drawing out findings relevant to low- and middle-income countries (LMICs). The aim of this study was to determine the extent to which SRs on risk factors for hearing loss reported findings associated with health inequities, and the extent to which this data was captured in the primary studies included within these SRs.

Methods

We identified SRs on risk factors for hearing loss from a report on this topic which included a systematic search for relevant SRs. SRs thus identified were inspected for data related to health inequity with reference to PROGRESS-Plus. We compared how data were reported in SRs versus within primary studies included in the SRs, and the extent to which primary studies from LMICs were represented.

Results

We included 17 SRs which reported findings on a variety of physiological, behavioral, demographic, and environmental risk factors for hearing loss. There were 296 unique primary studies included in the SRs, of which 251 (81.49%) were successfully retrieved. Data relating to health inequities was reported relatively infrequently in the SRs and mainly focused on gender and age. Data related to health inequities was more frequently reported in primary studies. However, several PROGRESS-Plus criteria were only reported in a minority of primary studies. Approximately one-third of primary studies were from LMICs.

Conclusions

There is scope to improve the reporting of data relating to health inequities in primary studies on risk factors for hearing loss. However, SR authors could do more to report health inequities than is currently undertaken, including drawing out findings relevant to LMICs where data are available.