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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 10  |  Issue : 17  |  Page : 25-29

Coronary atherosclerosis in diabetics: A postmortem teaching hospital experience in South-South Nigeria


1 Department of Anatomic Pathology, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria
2 Department of Morbid Anatomy, University of Benin Teaching Hospital, Benin City, Edo State, Nigeria

Date of Submission29-Mar-2020
Date of Decision11-Sep-2020
Date of Acceptance23-Nov-2020
Date of Web Publication24-Apr-2021

Correspondence Address:
Dr. Dele Eradebamwen Imasogie
Department of Morbid Anatomy, University of Benin Teaching Hospital, PMB 1111, Ugbowo Lagos Road, Benin City, Edo State
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/nnjcr.nnjcr_5_20

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  Abstract 


Context: Diabetes mellitus (DM) is a risk factor for the development of coronary artery disease. It is plausible that there is no significant association in the grade/severity of coronary atherosclerosis in diabetics in comparison with nondiabetics. Aims: The aim of this study, therefore, was to test this hypothesis by assessing the association of DM on the grade of coronary atherosclerosis. Settings and Design: This study was carried out at the Department of Morbid Anatomy, University of Benin Teaching as a prospective postmortem study. Subjects and Methods: This study employed consecutive sampling technique for recruiting the study population from June 1, 2012, to May 31, 2013. At postmortem, the coronary artery of each subject was graded into one of four grades on the basis of the percentage of cross-sectional area stenosis. Statistical analysis used: the data obtained were analyzed with Chi-square, Mann–Whitney U-test, Spearman's correlation, and multinomial logistic regression to determine the association/relationship between DM and coronary atherosclerosis. Results: Fifty-two cases constituted the study population. Their age ranged from 23 to 82 years with a mean age of 50.35 years (standard deviation = 16.62), median age of 50 years and modal age of 36 years. The severity of the grades of coronary atherosclerosis increased with age. There was a statistically significant association between the atherosclerotic grades of those participants with DM in comparison with those without the disease. Conclusion: The null hypothesis is therefore rejected as there is a statistical significant association in the grades of atherosclerosis in the study population with and without DM.

Keywords: Atherosclerosis, coronary artery disease, diabetes mellitus


How to cite this article:
Azeke AT, Imasogie DE. Coronary atherosclerosis in diabetics: A postmortem teaching hospital experience in South-South Nigeria. N Niger J Clin Res 2021;10:25-9

How to cite this URL:
Azeke AT, Imasogie DE. Coronary atherosclerosis in diabetics: A postmortem teaching hospital experience in South-South Nigeria. N Niger J Clin Res [serial online] 2021 [cited 2021 Jun 19];10:25-9. Available from: https://www.mdcan-uath.org/text.asp?2021/10/17/25/314603




  Introduction Top


Diabetes mellitus (DM) refers to a disorder of glucose metabolism that is predominantly typified by an increase in blood glucose levels, macrovascular, and microvascular complications which significantly increases the morbidity and mortality related to the disease.[1] This disorder predisposes to an increased risk of cardiovascular death and a higher incidence of cardiovascular diseases (CVDs) including but not limited to coronary artery diseases (CAD).[2] To this end, the determination of the association that exist between CAD and abnormal glucose homeostasis has been the center of extensive basic science, epidemiological, and therapeutic research studies.[2] Notable among these studies are the Framingham Heart Study and Atherosclerosis Risk in Communities Study.[3] Smith et al. observed that most of these studies were devoid of autopsy data, instead they make do with death certificates, medical records, questionnaires, and family interviews.[4] To correct this anomaly, autopsy studies and its generated data should be incorporated in epidemiological studies that aim to determine the link between risks factors including DM on one hand and CAD on the other hand. There is, however, a paucity of such studies in our own environment. It is likely that there is no significant statistical association on the grades/severity of coronary atherosclerosis in the diabetic in comparison with the nondiabetic. The aim of this study, therefore, was to test this hypothesis by assessing the association of DM on the grade of coronary atherosclerosis.


  Subjects and Methods Top


It was a prospective, postmortem study. The postmortem suite and the histopathology laboratory unit of the Department of Morbid Anatomy, University of Benin Teaching Hospital, Benin city, Edo State, South-South, Nigeria was the location for this study. This hospital serves as a tertiary referral center to all other secondary and primary health care facilities within Edo states and its catchment areas of Delta, Ondo, Kogi and Anambra states. This study was carried out over a 1-year period from June 1, 2012, to May 31, 2013. The age, sex, and the clinical history, including the information about the premorbid diabetic/nondiabetic state of each subject, were obtained from the patient's case file and or mortuary/autopsy register. Using this information, we employed the consecutive sampling technique for recruiting the study population. The target population consisted of adult subjects with a premorbid history of DM and an equal number of controls without a premorbid history of this disease. Hand lens were employed during the post-mortem of each subject to assess luminal narrowing of the left coronary artery (LCA) proximally at the level of the ostium in the root of the ascending aorta above the aortic valves, then 2–4 transverse serial sections along the course of the LCA were made. The most distal serial section was taken just above the bifurcation of the LCA into left circumflex artery and left anterior descending artery. These sections were reflected and with the aid of the hand lens assessed for luminal narrowing; the resultant stenosis was used to grade the coronary artery of each subject into one of four grades on the basis of the percentage of cross-sectional area stenosis.[5],[6] These grades ranged from Grade 0 (no narrowing/normal) to Grade IV (complete obliteration). Grade-0: normal, Grade-I: 1%–25% stenosis, Grade-II: 26%–50% stenosis, Grade-III: 51%–75% stenosis, and Grade-IV: 76%–100% stenosis.[5],[6] The data obtained were analyzed with the Statistical Package for the Social Sciences, software version 20 (SPSS 20, IBM Corp. Armonk, NY, US) using the Chi-square and Mann–Whitney test to determine the association between DM and coronary atherosclerosis with the level of statistical significance set at P ≤ 0.05. Spearman's correlation on SPSS was used to correlate the relationship between DM and coronary atherosclerosis. Multinomial logistic regression on SPSS was utilized to obtain the odds ratio which was used to measure the dependent relationship between diabetics (independent variable) and the severity of coronary atherosclerosis (dependent variable), whereas age, sex, and hypertension were used as co-independent variables in this analysis. Approval was obtained from the University of Benin Teaching Hospital ethics committee as recommended by the provisions of the declaration of Helsinki in 1995 (revised in Edinburgh 2000).[7]

A limitation of this study was its inability to predict the effect a change in all the known documented risk factors implicated in the development of atherosclerosis would have on the severity of the grades of coronary atherosclerosis in subjects with pre-morbid history of DM at postmortem.


  Results Top


There were 296 postmortems performed during the 1-year study period. Eighteen percent (52 cases) of these postmortems constituted the study population. Their age ranged from 23 to 82 years with a mean age of 50.35 years (standard deviation [SD] = 16.62), median age of 50 years and modal age of 36 years, as shown in [Table 1]. There were 35 males and 17 females giving a male-to-female ratio of 2.1:1. A bimodal peak age was each noted for Grades I, II, and III coronary atherosclerosis in the study population while an overall peak age for the lesion was observed in the sixth decade, as shown in [Table 2]. Fifty percent of the cases in this study was diabetics, as shown in [Table 2] and [Table 3]. Their age range was 42–82 years, with a mean age of 62.15 years (SD = 10.83), as shown in [Table 1]. Their median and modal ages were coincidentally 60 years. The males were 20, whereas the females were 6 giving a male-to-female ratio 3.3:1. The nondiabetics were the remaining 50% of the study population. Their age ranged from 23 to 59 years, whereas their mean, median, and modal ages were 38.54 (SD = 10.78), 36.50, and 36.00 years, respectively, as shown. The males were 15 participants while the females were 11 participants giving a male-to-female ratio of 1.4:1, as shown in [Table 1]. Participants with DM were associated with higher grade of atherosclerosis, as shown in [Table 2] where corresponding P values for Chi-square and Mann–Whitney U-tests were <0.05. Mann–Whitney U-test also showed that the average mean rank of the grade of coronary atherosclerosis in diabetics was higher (36.65) when compared with a lower value of 16.35 in nondiabetics. The presence of DM correlated with high grade of coronary atherosclerosis in a negatively but very strong relationship, as shown in [Table 2] by the Spearman's correlation coefficient. The odds of a diabetic developing Grade III coronary atherosclerosis relative to Grade I was 1.356E higher. [Table 2] shows that age and hypertension had a significant statistical association with the severity of coronary atherosclerosis while sex had no statistical significant association with the severity of coronary atherosclerosis. The age group, sex, and hypertensive distribution in diabetics/nondiabetics are shown in [Table 3].
Table 1: Demography of the study population

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Table 2: Risk factors distribution of the grades of coronary atherosclerosis in the study population

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Table 3: The age group, sex, and hypertensive distribution in diabetics/nondiabetics

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  Discussion Top


In an autopsy study over a 23-year period (1981–2004) from Olmsted County, Minnesota, USA, an increase in the grades of CAD since the year 2000 was noticed by Nemetz et al.[8] Nemetz et al. opinion may have resulted from the epidemic of obesity and its associated DM.[8] They therefore recommended further investigation for this association.[8]

Atherosclerosis begins in childhood, and its progression is influenced by the same risk factors as in adult CAD.[9] These risks factors had been determined from several prospective clinical studies to include but not limited to DM.[2],[3],[10],[11],[12],[13],[14],[15],[16]

Coronary artery atherosclerosis is more common, diffuse, and severe in diabetic participants than in nondiabetic participants.[1],[14] In our own study, the severity of coronary atherosclerosis was depicted by the grades that were more severe and statistically significant when comparison was made between diabetic and nondiabetic subjects. This is consistent with the findings of Waller et al. who observed more severe CAD at postmortem in diabetics when compared to the nondiabetics.[17] Giving credence to the role of diabetes as a risk factor in CAD, Goraya et al. noted that diabetic subjects without clinical evidence of CAD had high grade lesions at autopsy which were comparable to nondiabetic subjects that had clinically overt CAD.[18] Interestingly, the additive effect of some risk factors in the development of CAD had been brought to fore by Burchfiel et al. who examined the predictive association between DM and autopsy evidence of coronary atherosclerosis and myocardial lesions.[19] They reported that diabetic participants had more advanced coronary atherosclerotic lesion than nondiabetic control at autopsy. This they noted may be as a result of other risk factors associated with the development of CAD because less advanced lesions that were statistically insignificant (P = 0.102) were observed after adjustment for other cardiovascular risk factors.[19] Zengin et al. reported that DM has the strongest influence to predict secondary cardiovascular events in patients with known CAD.[20] This may be related to the findings of Burchfiel et al. that myocardial lesions occur more frequently in diabetics than nondiabetics even after adjustment for other risks factors, hence suggesting a role for nonatherogenic mechanism such as diabetes associated microvascular disease.[19] Aside Burchfiel et al. observation, it may be consistent with the hypothesis that the diabetic milieu has an impact on the progression of atherosclerotic lesions but not on their initiation.[21] This hypothesis is substantiated more by the observation that CAD does not occur in diabetic patients in populations with a low risk of CAD among nondiabetic patients.[21] Hyperinsulinemia may play a role, however the precise component of the diabetic milieu responsible for promotion of atherosclerotic lesions is unknown.[21]

The incidence of most of the major CVD risk factors is increasing in most groups of sub-Saharan Africa, including Nigeria, due to sociocultural and socioeconomic changes resulting in the epidemiological transition the region is passing through. Nigeria is at the threshold of this epidemiological transition.[13] This is as a result of exposure to western culture, technological developments, rapid urbanization, and acquisition of western lifestyles. This has resulted in the increasing incidence of the risk factors that predispose to atherosclerotic heart diseases and these factors include but not limited to DM.[13] This has heralded the emergence of CAD/myocardial infarction in South-South, Nigeria a condition that was once considered as uncommon.[13]

Males are more frequently affected by atherosclerosis than females.[22],[23] This is consistent with findings of this study. This is due to the protective effect of estrogen in females before menopause.[23],[24],[25]

At autopsy, the severity of coronary atherosclerosis has been shown to increase with age.[22],[26] This is consistent with the findings of this study that noted an association in the severity of coronary atherosclerosis with advancing age.

It is pertinent to note that diabetes has long been recognized to be an independent risk factor for CVD. Prospective studies, such as the Framingham, Honolulu, and San Antonio Heart Studies, as well as numerous more recent population studies in the United States and other countries, have documented excess CVD risk in patients with diabetes from multiple racial and ethnic groups.[10]


  Conclusion Top


This study noted a statistically significant rise in the grade of atherosclerosis with advancing age and hypertension just as a statistically significant association between higher atherosclerotic grade and diabetes was noted. The null hypothesis is therefore rejected. To this end, the conscious prevention and/or treatment of DM, a known modifiable risk factor in the development of atherosclerosis may be invaluable in decreasing the severity of coronary atherosclerosis and by extension deaths due to CAD.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Chiha M, Njeim M, Chedrawy EG. Diabetes and coronary heart disease: a risk factor for the global epidemic. International journal of hypertension 2012;1-7. Available at doi: 10.1155/2012/697240. Last viewed viewed on 4th February 2020.  Back to cited text no. 2
    
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Smith CJ, Scott SM, Wagner BM. The necessary role of the autopsy in cardiovascular epidemiology. Hum Pathol 1998;29:1469-79.  Back to cited text no. 4
    
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Prabhu MH, Siraj As, Begum A. Atherosclerosis of Coronary Arteries - An Autopsy Study. Global Journal of Medical Research Surgeries and Cardiovascular System. 2013;13:18-24. Available at: https://medicalresearchjournal.org/index.php/GJMR/article/download/399/17. Last accessed on 5th February, 2020.  Back to cited text no. 5
    
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Jiangping S, Zhe Z, Wei W, Yunhu S, Jie H, Hongyue W, et al. Assessment of coronary artery stenosis by coronary angiography: A head-to-head comparison with pathological coronary artery anatomy. Circ Cardiovasc Interv 2013;6:262-8.  Back to cited text no. 6
    
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Tyebkhan G. Declaration of Helsinki. Indian J Dermatol 2003;69:245-7.  Back to cited text no. 7
[PUBMED]  [Full text]  
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Nemetz PN, Roger VL, Ransom JE, Bailey KR, Edwards WD, Leibson CL. Recent trends in the prevalence of coronary disease: A population-based autopsy study of nonnatural deaths. Arch Intern Med 2008;168:264-70.  Back to cited text no. 8
    
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Dahl-Jørgensen K, Larsen JR, Hanssen KF. Atherosclerosis in childhood and adolescent type 1 diabetes: Early disease, early treatment? Diabetologia 2005;48:1445-53.  Back to cited text no. 9
    
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Diabetes mellitus: A major risk factor for cardiovascular disease. A joint editorial statement by the American Diabetes Association; The National Heart, Lung, and Blood Institute; The Juvenile Diabetes Foundation International; The National Institute of Diabetes and Digestive and Kidney Diseases; and The American Heart Association. Circulation 1999;100:1132-3.  Back to cited text no. 10
    
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Aronson D, Rayfield EJ. How hyperglycemia promotes atherosclerosis: Molecular mechanisms. Cardiovasc Diabetol 2002;1:1.  Back to cited text no. 11
    
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Bell DS. Diabetes mellitus and coronary artery disease. J Cardiovasc Risk 1997;4:83-90.  Back to cited text no. 12
    
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Essien OE, Andy J, Ansa V, Otu AA, Udoh A. Coronary artery disease and the profile of cardiovascular risk factors in South South Nigeria: A clinical and autopsy study. Cardiol Res Pract 2014;2014:804751.  Back to cited text no. 13
    
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Grundy SM, Benjamin IJ, Burke GL, Chait A, Eckel RH, Howard BV, et al. Diabetes and cardiovascular disease: A statement for healthcare professionals from the American Heart Association. Circulation 1999;100:1134-46.  Back to cited text no. 16
    
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Waller BF, Palumbo PJ, Lie JT, Roberts WC. Status of the coronary arteries at necropsy in diabetes mellitus with onset after age 30 years. Analysis of 229 diabetic patients with and without clinical evidence of coronary heart disease and comparison to 183 control subjects. Am J Med 1980;69:498-506.  Back to cited text no. 17
    
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Goraya TY, Leibson CL, Palumbo PJ, Weston SA, Killian JM, Pfeifer EA, et al. Coronary atherosclerosis in diabetes mellitus: A population-based autopsy study. J Am Coll Cardiol 2002;40:946-53.  Back to cited text no. 18
    
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Raguram R. (2019). Study of prevalence of coronary atherosclerosis in bodies subjected to autopsy belonging to age group 21-40 years in local population. (Unpublished postgraduate dissertation in forensic medicine). Tamilnadu DR.M.G.R. Medical University, Chennai. Available at http://repository-tnmgrmu.ac.in/10988/1/201400819raguram.pdf. Last accessed on 5th of February, 2020.  Back to cited text no. 23
    
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