Taking a health economic perspective in monitoring health inequalities: A focus on excess weight

Background: Traditional approaches to monitoring health inequalities predominantly rely on headcount methods. However, these methods fail to reflect the non-linear health economic implications of changes in disease severity. Alternative, distribution-sensitive metrics are available which could more adequately inform financial planning and policy decision making. Methods: We describe the design of the Foster-Greer-Thorbecke (FGT) index, and discuss its relative merits as a summary monitoring metric of health inequalities in the population, compared to the Erreygers concentration index. We illustrate the FGT index by conducting a comparative longitudinal analysis of adult excess inequalities in England using Health Survey for England data from 2009 to 2019. Findings: Excess weight inequalities have steadily increased in the English adult population, especially over the last five years. Going beyond headcount, the FGT index analyses revealed that, unlike the rest of the population, the average overweight adult from the most socio-economically deprived group is either obese (30.3 BMI for females) or at the brink of obesity (29.1 BMI for males). These results underscore a deepening divide in obesity severity between communities, with the most socioeconomically deprived groups being increasingly and disproportionally affected. Conclusions: The FGT index can address some shortcomings of traditional approaches to inequality measurement and local governments should consider adopting it as an alternative population health metric. Future research should apply and develop more refined distribution-sensitive measures of health inequality.