Distance as explanatory factor for sexual health centre utilization: an urban population-based study in the Netherlands

Background: The central sexual health centre (SHC) in the greater Rotterdam area in the Netherlands helps finding people unaware of their STI/HIV status. We aimed to determine a possible association between SHC utilization and travel distance in this urban and infrastructure-rich area. Insight in area-specific utilization helps adjust outreach policies to enhance STI testing. Methods: The study population consists of all residents aged 15-45 years in the greater Rotterdam area (2015-17). We linked SHC consultation data from STI tested heterosexual clients to the population registry. The association between SHC utilization and distance was investigated by multilevel modelling, adjusting for sociodemographic and area-specific determinants. The data were also stratified by age (aged < 25 years) and migratory background (non-Western), since SHC triage may affect their utilization. We used straight-line distance between postal code area centroid and SHC address as a proxy for travel distance. Results: We found large area variation in SHC utilization (range: 1.13-48.76 per 1000 residents). Both individual- and area-level determinants determine utilization. Travel distance explained most area variation and was inversely associated with SHC utilization when adjusted for other sociodemographic and area-specific determinants [odds ratio (OR) per kilometre: 0.95; 95% confidence interval (CI): 0.93-0.96]. Similar results were obtained for residents <25 years (OR: 0.95; 95% CI: 0.94-0.96), but not for non-Western residents (OR: 0.99; 95% CI: 0.99-1.00). Conclusions: Living further away from a central SHC shows a distance decline effect in utilization. We recommend to enhance STI testing by offering STI testing services closer to the population.