Prevalence of iron deficiency anemia in community-dwelling older persons as measured by the transferrin receptor-ferritin index

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

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.

Prevalence and incidence of iron deficiency in European community-dwelling older adults: an observational analysis of the DO-HEALTH trial

BACKGROUND AND AIM

Iron deficiency is associated with increased morbidity and mortality in older adults. However, data on its prevalence and incidence among older adults is limited. The aim of this study was to investigate the prevalence and incidence of iron deficiency in European community-dwelling older adults aged ≥ 70 years.

METHODS

Secondary analysis of the DO-HEALTH trial, a 3-year clinical trial including 2157 community-dwelling adults aged ≥ 70 years from Austria, France, Germany, Portugal and Switzerland. Iron deficiency was defined as soluble transferrin receptor (sTfR) > 28.1 nmol/L. Prevalence and incidence rate (IR) of iron deficiency per 100 person-years were examined overall and stratified by sex, age group, and country. Sensitivity analysis for three commonly used definitions of iron deficiency (ferritin < 45 μg/L, ferritin < 30 μg/L, and sTfR-ferritin index > 1.5) were also performed.

RESULTS

Out of 2157 participants, 2141 had sTfR measured at baseline (mean age 74.9 years; 61.5% women). The prevalence of iron deficiency at baseline was 26.8%, and did not differ by sex, but by age (35.6% in age group ≥ 80, 29.3% in age group 75-79, 23.2% in age group 70-74); P < 0.0001) and country (P = 0.02), with the highest prevalence in Portugal (34.5%) and the lowest in France (24.4%). As for the other definitions of iron deficiency, the prevalence ranged from 4.2% for ferritin < 30 µg/L to 35.3% for sTfR-ferritin index > 1.5. Occurrences of iron deficiency were observed with IR per 100 person-years of 9.2 (95% CI 8.3-10.1) and did not significantly differ by sex or age group. The highest IR per 100 person-years was observed in Austria (20.8, 95% CI 16.1-26.9), the lowest in Germany (6.1, 95% CI 4.7-8.0). Regarding the other definitions of iron deficiency, the IR per 100 person-years was 4.5 (95% CI 4.0-4.9) for ferritin < 45 µg/L, 2.4 (95% CI 2.2-2.7) for ferritin < 30 µg/L, and 12.2 (95% CI 11.0-13.5) for sTfR-ferritin index > 1.5.

CONCLUSIONS

Iron deficiency is frequent among relatively healthy European older adults, with people aged ≥ 80 years and residence in Austria and Portugal associated with the highest risk.