[Dual antiplatelet therapy and haemoglobin level: An observational study]

To determine the degree of association between dual antiplatelet therapy (DAPT) (clopidogrel plus acetylsalicylic acid) and haemoglobin (Hb) in clinical practice.

A retrospective longitudinal analysis was conducted on all patients on DAPT for at least 6 months. The required sample size was 63 patients. Hb value was determined before DAPT and at least 6 months after, as well as length of treatment, drugs, and diseases that might reduce the Hb. Changes in Hb after DAPT and the emergence or worsening of pre-existing anaemia was determined. Before and after Hb was compared using the t-test for paired samples. The occurrence of anaemia was considered dependent variable in a logistic regression analysis.

A total of 122 cases were included. There were 92 (75.4%) males, and the mean age was 74.5 (SD 9.9) years. DAPT duration was 19.3 (11.8) months. The pre-treatment Hb was 14.3 (1.4) g/dl and 12.8 (1.9) g/dl post-treatment. The prevalence of pre-DAPT anaemia was 9.1% (11 cases), and 45.9% post-treatment (56 cases). Comparison of means showed a decrease of 1.5g/dl (1.6) (95% CI; 1.2-1.8, P<.001). Anaemia post-treatment was associated with concomitant causes of anaemia, bleeding in the follow-up, and inversely with pre-treatment Hb level.

DAPT is associated with a decrease in Hb. Anaemia or worsening of previous anaemia appeared in about half of the subjects, and this effect was most likely in patients with bleeding in the follow-up and if other causes of anaemia were present.