Socioeconomic inequalities in healthcare utilization among older adults in Indonesia: social network mediation and dynamics before and after Universal Health Coverage

Background Socioeconomic inequalities in healthcare utilization (HCU) remain widespread in many low- and middle-income countries, even following major health system reforms. Social networks may influence individuals’ ability to access healthcare by providing information, resources, and support, yet their role in shaping socioeconomic inequalities in HCU remains poorly understood. This study examined whether social networks and their dynamics over time mediate the relationship between socioeconomic position (SEP) and HCU among older adults in Indonesia across periods before and during the implementation of Universal Health Coverage. Methods Data were drawn from the fourth (2007–2008) and fifth (2014–2015) waves of the Indonesian Family Life Survey, including 7,964 and 7,986 adults aged 50 and older, respectively. HCU outcomes included outpatient service use and participation in the posyandu lansia programme during the previous four weeks. SEP was modelled as a latent construct based on education, household expenditure, and wealth indicators. Social networks were conceptualized across four ecological levels (individual, family, community, and societal), and social network dynamics were assessed using a panel sample of 4,411 individuals participating in both waves. Causal mediation analysis was applied to estimate the proportion of the SEP–HCU relationship mediated by social network characteristics. Results HCU was higher in IFLS-5 than in IFLS-4, with outpatient service use rising from 16.9% to 24.6% and posyandu participation from 2.5% to 6.7%. Socioeconomic inequalities persisted, with higher SEP groups more likely to use outpatient services. Social network dynamics were common, with 36% of respondents experiencing changes over time, and were socially patterned, with lower SEP groups more likely to show increasing network trajectories. Loneliness and marital status mediated up to 7.3% of the association between SEP and outpatient service use, while community-level social networks mediated up to 21.7% of the relationship with posyandu participation. Conclusions Social networks contribute to explaining socioeconomic inequalities in HCU among older adults in Indonesia. The findings highlight the importance of both structural health system reforms and informal social support systems in shaping HCU. Strengthening community networks and addressing social isolation may complement improvements in formal healthcare coverage and help promote more equitable HCU in ageing populations.