Effect of Low-Dose Aspirin Versus Placebo on Incidence of Anemia in the Elderly : A Secondary Analysis of the Aspirin in Reducing Events in the Elderly Trial.

BACKGROUND

Daily low-dose aspirin increases major bleeding; however, few studies have investigated its effect on iron deficiency and anemia.

OBJECTIVE

To investigate the effect of low-dose aspirin on incident anemia, hemoglobin, and serum ferritin concentrations.

DESIGN

Post hoc analysis of the ASPREE (ASPirin in Reducing Events in the Elderly) randomized controlled trial. (ClinicalTrials.gov: NCT01038583).

SETTING

Primary/community care in Australia and the United States.

PARTICIPANTS

Community-dwelling persons aged 70 years or older (≥65 years for Black persons and Hispanic persons).

INTERVENTION

100 mg of aspirin daily or placebo.

MEASUREMENTS

Hemoglobin concentration was measured annually in all participants. Ferritin was measured at baseline and 3 years after random assignment in a large subset.

RESULTS

19 114 persons were randomly assigned. Anemia incidence in the aspirin and placebo groups was 51.2 events and 42.9 events per 1000 person-years, respectively (hazard ratio, 1.20 [95% CI, 1.12 to 1.29]). Hemoglobin concentrations declined by 3.6 g/L per 5 years in the placebo group and the aspirin group experienced a steeper decline by 0.6 g/L per 5 years (CI, 0.3 to 1.0 g/L). In 7139 participants with ferritin measures at baseline and year 3, the aspirin group had greater prevalence than placebo of ferritin levels less than 45 µg/L at year 3 (465 [13%] vs. 350 [9.8%]) and greater overall decline in ferritin by 11.5% (CI, 9.3% to 13.7%) compared with placebo. A sensitivity analysis quantifying the effect of aspirin in the absence of major bleeding produced similar results.

LIMITATIONS

Hemoglobin was measured annually. No data were available on causes of anemia.

CONCLUSION

Low-dose aspirin increased incident anemia and decline in ferritin in otherwise healthy older adults, independent of major bleeding. Periodic monitoring of hemoglobin should be considered in older persons on aspirin.

PRIMARY FUNDING SOURCE

National Institutes of Health and Australian National Health and Medical Research Council.