Do not leave men behind: socioeconomic inequality in undiagnosed diabetes in Indonesia 2013–2023

Abstract Background Despite the rollout of universal health coverage in 2014, undiagnosed diabetes remains high in Indonesia. This study assessed trends in socioeconomic disparities in undiagnosed diabetes from 2013 to 2023, focusing on sex differences and contributing factors. Methods We used biomedical subsamples from the 2013 and 2023 nationally representative Indonesian Health Surveys. Undiagnosed diabetes was defined as meeting the ADA 2020 criteria of diabetes without a self-reported diagnosis. Socioeconomic status was based on the household wealth index. Inequality was measured using the Erreygers Concentration Index (ECI), where negative values indicate greater burden among the poor. We conducted regression-based decomposition to identify key contributors, stratified by sex and adjusted for survey design. Results The prevalence of undiagnosed diabetes declined from 87.9% in 2013 to 79.9% in 2023 (P < 0.001). Socioeconomic inequality also narrowed (ECI: −0.134 to − 0.084, P < 0.001), though the burden remained concentrated among poorer individuals. Inequality fell significantly among women (−0.131 to − 0.050, P < 0.05) but remained unchanged among men (−0.141 to − 0.143, P > 0.05). Education, urban residence, and agricultural work were key contributors. In 2023, formal employment reduced inequality among men by 45%, driven by increased undiagnosed diabetes among this group, concentrated among wealthier men. Among women, being aged 45-74 and having lower education reduced inequality by 16% and 17%, respectively, as both were linked to lower undiagnosed diabetes risk and were more common among poorer women. Conclusions While the overall inequality of undiagnosed diabetes has declined, persistent disparities among men highlight missed opportunities. A narrowing gap due to worsening outcomes among advantaged groups is concerning. Targeted efforts, especially for men in formal jobs, are needed to improve early detection and prevent a widening gender gap in undiagnosed diabetes. Key messages • Universal health coverage has helped reduce undiagnosed diabetes and improved access to care among lower socioeconomic groups in Indonesia. • Despite a reduction in the overall socioeconomic inequality in undiagnosed diabetes, no significant progress was made among men, highlighting the need for targeted, gender-sensitive interventions.