Abstract
This study aimed to find an association between ABO blood groups with presence and severity of Coronary artery disease (CAD) among Indian population. 1500 patients undergoing elective coronary angiogram (CAG) at a tertiary care hospital in Karnataka were enrolled in the study. Baseline demographic data and the presence of cardiac comorbidities were documented. Data from baseline echocardiography and angiographic studies were compiled. The incidence of CAD was higher among patients with blood group A. Blood group A also showed a higher incidence of acute coronary syndrome (ACS), left ventricular dysfunction, triple vessel disease, and severe CAD among the patients who underwent CAG.
Keywords: ABO blood Group, Coronary artery disease, Gensini score
1. Introduction
Coronary artery disease (CAD) is a multifactorial condition and is considered one of the major concerns of cardiovascular disease.1,2 Currently CAD is one of the leading causes of death in industrialized to developing countries.3, 4, 5 Influence of cumulative pathologic effects from various cardiovascular risk factors plays a potential role in the development of CAD. In the process of disease progression, these cohorts present with myocardial Infarction (MI), heart Failure (HF) or cardiac arrhythmias.6,7
There is a significant number of patients who suffer from an MI but do not possess any of the major risk factors. In this context, studies focusing on the association between the ABO blood grouping and CAD have documented that the presence of a locus on 9p21 tends to play an important part in the progression of CAD.8
Therefore, based on the preliminary data, we sought to further exploit the relationship between the ABO blood groups and CAD and the severity of CAD in the South Indian population.
2. Materials and method
A prospective observational study was carried out between October 2019 and August 2021 at a tertiary care hospital in the coastal region of South Karnataka under the Department of Cardiology after approval from the Institutional Ethics Committee (IEC 762/2019). Patients admitted to the hospital with clinical suspicion or known CAD and were posted for CAG were included in the study. Patients with stroke, chronic obstructive pulmonary disease (COPD), cerebral Vascular Accident (CVA), chronic kidney disease (CKD) on dialysis, malignant disease, significant renal or liver insufficiency, serious acute HF with multiorgan dysfunction, significant hemolytic disorders and infections or systemic illnesses were excluded. A total of 1500 patients were enrolled in the study after they met both the inclusion and exclusion criteria.
Baseline data including age, gender, height, weight, body mass Index (BMI), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were collected and documented for each patient. Comorbidities were documented for each patient. As part of the laboratory investigations; lipid profile parameters were logged. LV systolic function status was documented. Coronary angiogram findings were documented and lesions >50% were considered significant. The severity of CAD was assessed using the Gensini score (GS) which incorporates the extent of stenosis and the anatomical location depending on the coronary circulation.9 All the data obtained were analyzed using Statistical Package for Social Sciences (SPSS) software version 16. One-way ANOVA and Kruskal Wallis tests were used to compare the mean and median values between the 4 groups. The Chi-square test was used to find the association between the 2 categorical variables. A P value of <0.05 was considered statistically significant.
3. Results
Out of the 1500 enrolled patients, the O group was the most prevalent blood group found in 37.1% patients followed by blood group A (30.6%), blood group B (25.5%), and blood group AB (6.7%). 1 individual had a rare group called Bombay blood group. Among 1500 study participants, 1086 patients (72.4%) were diagnosed with CAD. There were 1028 (68.53%) males and 472 (31.46%) females in the study population.
Table 1 shows the baseline characteristics, cardiac risk factors, and lipid profile among the 4 categories of the blood group. There was a statistically significant association between the blood group and hypertension where blood group AB had a higher prevalence of hypertension compared to other groups. Other risk factors such as Diabetes Mellitus (DM), family history of MI, previous MI were not associated with the blood group category. Likewise, lipid profile parameters did not differ among the four blood groups. LV dysfunction with EF <55% was more evident among blood group A category compared to other groups. Prevalence of acute coronary syndrome (ACS) was higher among blood group A compared to B, AB and O groups. Triple Vessel disease (TVD) was observed to be the highest among blood group A (32.5%) compared to the other blood groups whereas blood group O had the highest frequency of patients with normal coronaries (31.3%) [P < 0.001]. These findings were also supported by the Gensini score which illustrated that blood group A had a higher median value for the severity of CAD in comparison to blood group B, AB, and [Table 2]. Among 414 Non-CAD group, the O group was the commonest blood group found in 174 (42.02%), followed by B group 125 (30.19%), AB group 29 (7%), and A group 86 (20.77%).
Table 1.
Demographic parameters, clinical profile, and lipid profiles among ABO blood groups.
| Blood Group Variable |
A (n = 459) [n (%)] or [Mean ± SD] | B (n = 383) [n (%)] or [Mean ± SD] | AB (n = 101) [n (%)] or [Mean ± SD] | O (n = 566) [n (%)] or [Mean ± SD] | p VALUE |
|---|---|---|---|---|---|
| Age | 60.98 ± 11.28 | 59.92 ± 11.54 | 59.64 ± 11.70 | 59.84 ± 11.92 | 0.541 |
| Gender | |||||
| Male | 319 (69.5%) | 263 (68.7%) | 64 (63.45) | 381 (68.5%) | 0.786 |
| Female | 140 (30.5%) | 120 (31.3%) | 37 (36.6%) | 175 (31.5%) | |
| Demographic parameters | |||||
| Height | 162.01 ± 6.19 | 162.51 ± 6.44 | 161.66 ± 5.8 | 161.42 ± 8.41 | 0.219 |
| Weight | 60.89 ± 7.44 | 61.22 ± 8.32 | 60.9 ± 7.54 | 61.24 ± 8.23 | 0.775 |
| BMI | 23.27 ± 3.17 | 23.20 ± 3.01 | 23.36 ± 2.96 | 23.82 ± 7.86 | 0.333 |
| SBP | 128.86 ± 21.06 | 128.87 ± 18.43 | 128.10 ± 17.16 | 131.47 ± 21.41 | 0.291 |
| DBP | 78.15 ± 11.22 | 78.89 ± 10.76 | 78.16 ± 10.29 | 80.24 ± 28.19 | 0.523 |
| Lipid Profile | |||||
| HDL | 49.97 ± 10.82 | 41.50 ± 11.87 | 42.35 ± 10.43 | 41.67 ± 12.32 | 0.960 |
| LDL | 110.58 ± 45.68 | 109.30 ± 69.45 | 104.15 ± 44.56 | 107.15 ± 47.14 | 0.670 |
| TC | 171.12 ± 51.25 | 166.14 ± 51.39 | 165.18 ± 51.72 | 168.90 ± 54.48 | 0.539 |
| Risk Factors | |||||
| Hypertension | 281 (61.2%) | 202 (52.7%) | 65 (64.4%) | 318 (57.2%) | 0.050 |
| DM | 204 (44.4%) | 157 (41.0%) | 35 (36.6%) | 206 (37.1%) | 0.080 |
| F/H/O MI | 58 (12.7%) | 55 (14.4%) | 8 (7.9%) | 79 (14.2%) | 0.412 |
| Previous MI | 82 (18.0%) | 65 (17.0%) | 18 (17.8%) | 77 (14.0%) | 0.430 |
| Smoking | 89 (19.4%) | 74 (19.3%) | 19 (18.8%) | 109 (19.6%) | 0.999 |
| Alcohol | 64 (13.9%) | 62 (16.2%) | 17 (16.8%) | 87 (15.7%) | 0.790 |
| Ejection Fraction (EF) | |||||
| >55% | 239 (52.1%) | 218 (56.9%) | 61 (60.4%) | 337 (60.6%) | <0.001 |
| 45–55% | 109 (23.7%) | 78 (20.4%) | 17 (16.8%) | 115 (20.7%) | |
| 35–45% | 79 (17.2%) | 66 (17.2%) | 16 (15.8%) | 82 (14.7%) | |
| <35% | 32 (7.0%) | 21 (5.5%) | 7 (6.9%) | 22 (4.0%) | |
BMI:Body Mass Index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure, HDL: High density lipd; LDL: Low density lipid; TC: Total cholesterol; DM: Diabetes Mellitus; F/H/O MI: Family history of myocardial infarction.
Table 2.
Association between CAD and its severity with the ABO blood group.
| Blood Group Variable |
A (n = 459) [n (%)] or [Median (IQR) | B (n = 383) [n (%)] or [Median (IQR) | AB (n = 101) [n (%)] or [Median (IQR) | O (n = 556) [n (%)] or [Median (IQR) | p VALUE |
|---|---|---|---|---|---|
| CAD | 373 (81.26%) | 253 (66.06%) | 72 (71.29%) | 382 (67.49%) | <0.001 |
| Number of vessels | |||||
| Zero Vessel | 86 (18.7%) | 125 (32.6%) | 29 (28.7%) | 174 (31.3%) | <0.001 |
| 1 Vessel | 101 (22.0%) | 84 (21.9%) | 17 (16.8%) | 145 (26.1%) | |
| 2 Vessel | 123 (26.8%) | 83 (21.7%) | 32 (31.7%) | 115 (20.7%) | |
| 3 Vessel | 149 (32.5%) | 91 (23.8%) | 23 (23.85%) | 122 (21.95%) | |
| LMCA Stenosis | 30 (6.5%) | 20 (5.2%) | 6 (5.9%) | 22 (4.0%) | 0.334 |
| Type Of Diseases | |||||
| Normal | 84 (18.3%) | 124 (32.4%) | 29 (28.7%) | 173 (31.1%) | <0.001 |
| STEMI | 135 (29.4%) | 98 (25.6%) | 21 (20.8%) | 119 (21.4%) | |
| NSTEMI | 159 (34.6%) | 105 (27.4%) | 29 (28.7%) | 146 (26.3%) | |
| Unstable Angina | 61 (13.3%) | 48 (12.5%) | 20 (19.8%) | 105 (18.9%) | |
| Chronic stable angina | 20 (4.4%) | 8 (2.1%) | 2 (2.0%) | 13 (2.3%) | |
| Gensini Score | 39 (14, 70) | 28 (2, 52) | 32 (3, 67.25) | 22.25 (2.5, 51.38) | <0.001 |
LMCA: Left main coronary artery; STEMI:ST elevation MI; NSTEMI: Non-ST elevation MI.
4. Discussion
There were 1086 (72.4%) patients who were diagnosed to have CAD. Blood group distribution across the study group showed O group as the most prevalent followed by A, B and AB group. The incidence of CAD was significantly higher in blood group A (81.26%) than in the other blood groups with the least occurrence in group B (66.06%). Furthermore, a meta-analysis by Zhuo Chen et al documented 17 studies showed that the risk of developing CAD was significantly higher in blood group A and Non-O group.10 Likewise, several reports from different populations such as Taiwanese, American, British and Chinese were consistent with our results [11–20]. Among Indian studies, Garg et al found that the risk of CAD was significantly higher in blood group B than in the other groups. This cross-sectional study compared 200 MI and 200 healthy control population, where they aimed to find the association between MI and ABO group. However, their study was limited by the relatively small sample size and the involvement of only ACS.11 Wherein our study involved all the CAD including chronic stable angina, and acute coronary syndrome subtypes, and found an association with the ABO group. Yet, blood group A showed a higher incidence of MI and overall CAD.
Gensini score was found to be higher in blood group A compared to other blood groups. In a cross-sectional study conducted by Xu-Lin Hong et al, a significant higher Gensini score in the blood group A than in the Non-A groups was seen.12 Likewise, Ping Gong et al demonstrated an association between ABO blood groups and increased severity of CAD where blood group A was independently associated with the severity of CAD.13
Moreover, preventive strategies for CAD can be formulated by identifying as many risk factors associated with CAD as possible. Risk factors, such as tobacco use, smoking, hypertension (HTN), diabetes mellitus (DM), dyslipidemia, increased intake of processed and unhealthy food, psychological factors, sedentary lifestyle, old age, gender, family history of CAD, ethnicity, and obesity are basically classified under modifiable and non-modifiable risk factors for cardiovascular diseases.4,14 Nevertheless, there is a significant number of patients who do not possess any of the major risk factors but present with MI. This prompts an alternative explanation or the presence of a genetic risk factor that hasn't been studied thoroughly. Studies focusing on the association between the ABO blood grouping and CAD have documented that the presence of a locus on 9p21 tends to play an important part in the progression of CAD. Reduction in the cardiac expression of CDKN2A/B due to the targeted deletion of the 9p21 locus remains the most common mechanism for the inactivation of methylthioadenosine phosphorylase leading to a less stable plaque phenotype in the artery.8 ABO blood group seemed to have an impact on coronary artery disease and the type of blood group affected the severity of CAD. However, the literature has inconsistent results with respect to the association between ABO and the presence of CAD. Further thorough investigations are essential to discover the clinical utility of emerging markers in a larger cohort and in a multicenter setting in order to establish the association between the ABO blood group and stratification or prediction of future CAD events with their genetic background.
5. Conclusion
In summary, we observed a higher incidence of CAD along with more severe form of atherosclerosis in patients with A blood groups compared to controls. Moreover, blood group A had a higher incidence of CAD, ACS, and LV dysfunction compared to other blood group categories. In the future, population-based studies comprising a large cohort of data may highlight the significance and genetic aspect of the ABO blood group and their association with the occurrence, disease pathology, and prognosis of CAD.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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References
- 1.McCullough P.A. Coronary artery disease. Clin J Am Soc Nephrol. 2007 May 1;2(3):611–616. doi: 10.2215/CJN.03871106. [DOI] [PubMed] [Google Scholar]
- 2.Zhao Q., Chen X., Zhang X., Nie M., Yan Y. The relationship between ABO blood group and coronary artery disease: a systematic review and meta-analysis. J Cardiovasc Dis Diagn. 2018;6(340):2. [Google Scholar]
- 3.Ralapanawa U., Sivakanesan R. Epidemiology and the Magnitude of Coronary Artery Disease and Acute Coronary Syndrome: A Narrative Review. J Epidemiol Glob Health. 2021 Jun;11(2):169–177. doi: 10.2991/jegh.k.201217.001. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Pandey R.A., Khadka I. Knowledge regarding preventive measures of heart disease among the adult population in Kathmandu. Health. 2012 Sep 28;4(9):601. [Google Scholar]
- 5.Zeller T., Seiffert M., Müller C., et al. Genome-wide association analysis for severity of coronary artery disease using the Gensini scoring system. Frontiers in cardiovascular medicine. 2017 Sep 20;4:57. doi: 10.3389/fcvm.2017.00057. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Libby P., Theroux P. Pathophysiology of coronary artery disease. Circulation. 2005 Jun 28;111(25):3481–3488. doi: 10.1161/CIRCULATIONAHA.105.537878. [DOI] [PubMed] [Google Scholar]
- 7.Tegos T.J., Kalodiki E., Sabetai M.M., Nicolaides A.N. The genesis of atherosclerosis and risk factors: a review. Angiology. 2001 Feb;52(2):89–98. doi: 10.1177/000331970105200201. [DOI] [PubMed] [Google Scholar]
- 8.Tajbakhsh A., Khorrami M.S., Hassanian S.M., et al. The 9p21 locus and its potential role in atherosclerosis susceptibility; molecular mechanisms and clinical implications. Curr Pharmaceut Des. 2016;22(37):5730–5737. doi: 10.2174/1381612822666160628082453. [DOI] [PubMed] [Google Scholar]
- 9.Gensini G.G. A more meaningful scoring system for determining the severity of coronary heart disease. Am J Cardiol. 1983 Feb 1;51(3):606. doi: 10.1016/s0002-9149(83)80105-2. [DOI] [PubMed] [Google Scholar]
- 10.Chen Z., Yang S.H., Xu H., Li J.J. ABO blood group system and the coronary artery disease: an updated systematic review and meta-analysis. Sci Rep. 2016 Mar 18;6(1):1. doi: 10.1038/srep23250. 1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Garg P., Kumar J., Choudhary R., Chawla V.K. Association between ABO blood groups and myocardial infarction in Jodhpur city of India. J Bangladesh Soc Physiol. 2012 Jul 10;7(1):13–17. [Google Scholar]
- 12.Hong X.L., Li Y., Fu G.S., et al. Association of ABO blood groups with the severity of coronary artery disease: a cross-sectional study. Journal of geriatric cardiology: JGC. 2019 Sep;16(9):701. doi: 10.11909/j.issn.1671-5411.2019.09.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Gong P., Luo S.H., Li X.L., et al. Relation of ABO blood groups to the severity of coronary atherosclerosis: an Gensini score assessment. Atherosclerosis. 2014 Dec 1;237(2):748–753. doi: 10.1016/j.atherosclerosis.2014.10.107. [DOI] [PubMed] [Google Scholar]
- 14.Danaei G., Ding E.L., Mozaffarian D., et al. The preventable causes of death in the United States: comparative risk assessment of dietary, lifestyle, and metabolic risk factors. PLoS Med. 2009 Apr 28;6(4) doi: 10.1371/journal.pmed.1000058. [DOI] [PMC free article] [PubMed] [Google Scholar]