Prognostic impact of anaemia on patients with ST-elevation myocardial infarction treated by primary PCI.
OBJECTIVE
The aim of this study was to investigate the effects of baseline anaemia on the outcome in patients treated by primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction.


METHODS
This study was a retrospective cohort study of 2418 patients with ST-elevation myocardial infarction treated by PPCI between January 2004 and August 2010 at a single centre. We investigated the outcome in patients with anaemia compared with that in patients with a normal haemoglobin (Hb) level. Anaemia was defined according to the WHO definition as an Hb level less than 12 g/dl for female individuals and less than 13 g/dl for male individuals. We also calculated hazard ratios using a stratified model according to the Hb level.


RESULTS
A total of 471 (19%) patients were anaemic at presentation. The anaemic cohort was older (72.2 vs. 62.4 years, P<0.0001) and had a higher incidence of diabetes (28 vs. 16%, P<0.0001), hypertension (57 vs. 43%, P=0.01), hypercholesterolaemia (48 vs. 40%, P=0.007), previous PCI (15 vs. 9%, P<0.0001), previous myocardial infarction (23 vs. 12%, P=0.002), and cardiogenic shock (12 vs. 5%, P<0.0001). Over a mean follow-up period of 3 years there was significantly higher all-cause mortality in the anaemic group compared with the normal Hb group (20.4 vs. 13.5%, P<0.0001). However, after adjustment for all variables using multivariate analysis, anaemia (on the basis of the WHO definitions) was found not to be an independent predictor of mortality or major adverse cardiac events over the follow-up period. Further, when we used a model stratified by g/dl, we found that there was an increased risk for adverse outcomes among men with low Hb levels. There appeared to be a threshold value of Hb (13 g/dl) associated with increased risk. Although a similar trend was observed among women, no significant difference was observed.


CONCLUSIONS
Patients with anaemia undergoing PPCI are at a higher risk of an adverse outcome. Anaemia is a simple and powerful marker of poor prognosis. Although anaemia (based on the WHO definitions) does not appear to be an independent predictor of all-cause mortality or major adverse cardiac events after PPCI on multivariate analysis, there appears to be a threshold value of Hb among men, below which there is an associated increased risk for PPCI.
aDepartment of Cardiology, Barts and the London NHS Trust bDepartment of Clinical Pharmacology, William Harvey Research Institute, Queen Mary University cNIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Krishnaraj S
KS
Rathod
Daniel A
DA
Jones
Vrijraj S
VS
Rathod
Daniel
D
Bromage
Oliver
O
Guttmann
Sean M
SM
Gallagher
Saidi
S
Mohiddin
Martin T
MT
Rothman
Charles
C
Knight
Ajay K
AK
Jain
Akhil
A
Kapur
Anthony
A
Mathur
Adam D
AD
Timmis
Rajiv
R
Amersey
Andrew
A
Wragg
D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D015415:Biomarkers / Q000097:blood; D015897:Comorbidity; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D008131:London / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
D015415:Biomarkers; D006454:Hemoglobins