Table 3.
Studies exploring association between red blood cell distribution width (RDW) and myocardial infarction (MI).
| First author, journal, year | Study design | Study population | Mean follow-up | Major outcomes | Major limitations |
|---|---|---|---|---|---|
| (i) Tonelli et al. [20]
(ii) Circulation (iii) 2008 |
Post hoc analysis | 4111 participants with hyperlipidemia and a history of myocardial infarction, age 21–75 years | A median of 59.7 months | The top RDW quartile had a 56% increased risk of fatal coronary disease or nonfatal myocardial infarction when compared to subjects in the lowest quartile (HR 1.56, 95% CI 1.17–2.08) | (i) Not rule out the possibility of residual confounding
(ii) The samples cannot not be representative of the general population |
| (i) Chen et al. [51]
(ii) American Journal of Epidemiology (iii) 2010 |
Prospective cohort | 3226 participants without history of stroke, coronary heart disease, or cancer, age>35 years | A median of 15.9 years | The highest RDW quartile was 1.46 for all-cause mortality compared with the lowest quartile (95% CI: 1.17–1.81) | (i) Few cases met the anemia criteria, which resulted in fairly wide confidence intervals
(ii) Not reported data on specific causes of non-CVD death (iii) Only measured the RDW values once |
| (i) Zalawadiya et al. [52]
(ii) American Journal of Cardiology (iii) 2010 |
Multiethnic cohort | 7556 participants, age 41.5–15.8 years | 10 years | The risk of being classified in the intermediate risk category of coronary heart disease was 53% greater (95% CI: 1.38–1.69, p < 0.001) with each unit increase in RDW value | (i) Actual cardiovascular events during a set follow-up period was unavailable |
| (i) Lee et al. [53]
(ii) Clinical Cardiology (iii) 2013 |
Retrospective analysis | 1596 patients with acute myocardial infarction, mean age, 64.5 ± 11.9 years | 1634 ± 342 days | The RDW levels were significantly higher in patients with 12-month major adverse cardiac events (13.8 ± 1.3% versus 13.3 ± 1.2%, p < 0.001) | (i) Cannot exclude the possibility of residual confounding factors
(ii) Not adjusted the RDW for nutrients (such as iron, folate, and vitamin B12) |
| (i) Arbel et al. [54]
(ii) Thrombosis and Haemostasis (iii) 2014 |
Registry-based, retrospective cohort | 225,006 subjects from health registry, age ≥ 40 years | 5 years | Compared to patients with a RDW of 13% or lower, patients with RDW > 17% had a HR of 3.83 (95% CI: 3.12–4.69, p < 0.001) for all-cause mortality and 1.22 (95% CI: 1.04–1.42, p = 0.01) for major adverse cardiac events | (i) Not rule out the possibility of residual confounding
(ii) Not reported data on specific causes of non-CVD death |
| (i) Skjelbakken et al. [125]
(ii) Journal of the American Heart Association (iii) 2014 |
Prospective cohort | 25,612 participants with no previous myocardial infarction, mean age 40.2–52.8 years | 15.8 years | There was a linear association between RDW and risk of myocardial infarction, for which a 1% increment in RDW was associated with a 13% increased risk (HR 1.13; 95% CI: 1.07–1.19) | (i) The RDW measure was not repeated, there remained random measurement error
(ii) Participants may underestimate the true prevalence of diabetes |
| (i) Sun et al. [22]
(ii) Cardiology (iii) 2014 |
Prospective cohort | 691 patients with STEMI, free of heart failure | 41.8 months | High RDW was associated with all-cause mortality (HR: 3.43; 95% CI: 1.17–8.32; p = 0.025) | (i) Not rule out the possibility of residual confounding
(ii) The sample size was relatively small |
| (i) Sahin et al. [126]
(ii) Medical Principles and Practice (iii) 2015 |
Cross-sectional study | 335 patients with NSTEMI, age 50–79 years | A median of 18 ± 11 months | The RDW levels of patients were significantly higher in the high SYNTAX group than in the low SYNTAX group (15.2 ± 1.8 versus 14.2 ± 1.2, p < 0.001) | (i) The sample size was relatively small
(ii) Only measured hemoglobin levels, but not other factors such as iron, vitamin B12 and folate |
| (i) Sahin et al. [126]
(ii) Clinics (iii) 2015 |
Cross-sectional study | 251 adult patients with NSTEMI over a 1-year period, age >50 years | — | The RDW was higher in the group with non-ST-elevation myocardial infarction compared with the patient group with unstable angina (14.6 ± 1.0 versus 13.06 ± 1.7, resp., p = 0.006) | (i) The sample size was relatively small
(ii) Only Hb levels were measured in the study |