Undernutrition and Increased Healthcare Demand: Evidence from a Community-Based Longitudinal Panel Study in Singapore

Background/Introduction: Undernutrition's impact on healthcare utilisation across age groups and care settings remains underexplored, particularly in Asian contexts. This study investigated the dynamic association between nutritional status and healthcare utilisation among community-dwelling adults in Singapore and assessed whether age modified this relationship. Methods: The study sampled 1703 adults enrolled in the Population Health Index study. Nutritional status was assessed annually using the Mini Nutritional Assessment, and healthcare utilisation data-across primary care, specialist outpatient clinics (SOCs), emergency departments (EDs), day surgeries, and inpatient admissions-were extracted from administrative databases. Negative binomial regressions with interaction terms using longitudinal panel data were conducted to examine age-modified effects. Results: At baseline, 9.7% of participants were classified as undernourished, with a higher prevalence in older adults (15.0%). Key risk factors for undernutrition included female sex, unemployment, financial inadequacy, currently smoking, lack of formal education, and multimorbidity. Undernutrition was associated with increased ED visits (IRR 1.41, AME: 0.35) and inpatient admissions (IRR 1.52, AME: 0.42). Among older adults, undernutrition was associated with less primary and specialist care (IRR: 0.72 and 0.57), while younger undernourished adults had more SOC visits (AME: 0.46). Older undernourished adults had 0.46 more ED visits and 0.47 more inpatient admissions on average in one year, though these increases did not differ from younger adults (interaction p > 0.05). Conclusions: Undernutrition is associated with increased ED visits and inpatient admissions, especially in older adults. Integrating nutritional screening and targeted interventions into community and primary care may help reduce preventable hospitalisations in high-risk populations.