Low-dose acetylsalicylic acid use and hemoglobin levels. Effects in a primary care population.

OBJECTIVE

To determine the prevalence of acetylsalicylic acid therapy and effect of the drug on hemoglobin concentration over time.

DESIGN

Retrospective, observational study.

SETTING

Primary care population in a university-affiliated family medicine clinic.

PATIENTS

A population-based sample of 80 patients receiving low-dose ASA for secondary prevention of cardiovascular disease was studied. Of 84 patients receiving the drug after a cardiovascular problem, four were excluded: one man died of a recurrent stroke during the study; the file of a second man was unavailable; another man developed a bleeding ulcer; and one woman had been taking ASA for only 1 month when the data were collated.

MAIN OUTCOME MEASURES

Demographic variables of patients taking low-dose ASA, duration of ASA use, and two successive measures of hemoglobin level.

RESULTS

The frequency of ASA administration was 7.7% for men aged 60 and older and 2.9% for women. Women had no significant change in hemoglobin levels, while men had a mean loss of 0.472 g/dL (95% confidence interval, .198 to .746; P = .009). For the study population as a whole (80 patients), the average decline was 0.294 g/dL (95% confidence interval, .039 to .549; P = .029).

CONCLUSIONS

Although the clinical significance of these findings is uncertain, they suggest the need for a prospective investigation of the influence of low-dose ASA on hemoglobin levels.