Association between iron deficiency and hospitalization rate in community-dwelling older adults: A 3-year prospective observational study of DO-HEALTH

Abstract

Background: Iron deficiency (ID) is associated with negative health outcomes in older adults. However, data on the impact of ID on the number of hospitalizations and length of hospital stay (LOS) is lacking. Objective: To explore the associations between baseline ID and the number of hospitalizations and between baseline ID and at least one LOS ≥5 days in community-dwelling older adults. Methods: This is a secondary observational analysis of a randomized controlled trial including 2157 community-dwelling adults aged ≥70 years without major diseases at baseline. The main exposure was defined as ID (soluble transferrin receptor [sTfR] concentrations >28.1 nmol/L) at baseline. The primary outcome was the number of hospitalizations over a 3-year follow-up. The secondary outcome was having at least one LOS ≥5 days over the study period among individuals with one or more hospitalizations. Interaction between ID and anemia (hemoglobin <130 g/L for men and <120 g/L for women) was also investigated. Results: Baseline sTfR concentration was determined in 2141 participants (median age 74.0 years). At 3 year, 1497 hospitalizations were reported with an incidence rate of hospitalization of 0.26 per person-year (95% CI: 0.24, 0.28). Overall, baseline ID was associated with a 24% increased incidence rate of hospitalization (incidence rate ratio: 1.24; 95% CI: 1.05, 1.45) over 3 years. This association was independent of anemia status at baseline since the interaction between ID and anemia at baseline was not significant. Moreover, ID was not significantly associated with having a LOS ≥5 days (OR: 1.40; 95% CI: 1.00, 1.97) among participants with at least one hospitalization over 3 years. Conclusions: ID is associated with increased hospitalization rate and not associated with LOS ≥5 days among generally healthy older adults. Efforts to minimize ID in older adults may improve overall health and optimize healthcare costs.