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European Journal of Applied Sciences – Vol. 10, No. 2
Publication Date: April 25, 2022
DOI:10.14738/aivp.102.11899. Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of
Cardiovascular Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied
Sciences, 10(2). 362-379.
Services for Science and Education – United Kingdom
Prevalence of Cardiovascular Diseases and Associated Factors
Among Patients in Low- and Middle-Income Settings
Samwel Jacob Rweyemamu
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
Tatizo Waane
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
George L. Longopa
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
Peter Richard Kisenge
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
Sophia Bishashara
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
Rosemary Mpella
Jakaya Kikwete Cardiac Institute, P. O. Box 65141
Dar es Salaam, Tanzania
Reuben Mutagaywa
School of Medicine, Muhimbili University of Health and
Allied Sciences, P.O. BOX 65001, Tanzania
ABSTRACT
Background: Cardiovascular Diseases (CVDs) are the public health problems
worldwide, causing over 18.9 million deaths per year. The major risk factors which
are also preventable are tobacco use, diabetes, high blood pressure, overweight/
obesity and alcohol consumption. The aim of this study was to determine the
Prevalence of CVDs and associated factors. Methodology: We conducted a cross- sectional hospital-based study that consecutively enrolled 785 consenting adults
who came to attend Jakaya Kikwete Cardiac Institute (JKCI) mobile clinic in South
Western urban Tanzania, a typical LMIC, in 2018. A structured questionnaire was
used to obtain demographic data and gather several co-morbid information. A 12
lead Electrocardiogram (ECG) and 2D, M mode Transthoracic Echocardiogram were
done to determine the structural and none structural heart diseases from the
participants. Results: Of 785 participants, 528 (67.3 %) were females, 479 (61%)
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
were middle aged (40-60 years) and 196 (25%) were 65 years old and above, their
mean age (±SD) was 56 (±14) years. Most of participants were married 558 (71%),
625 (80%) sponsored by the National Health Insurance Fund (NHIF) and less than
half were employed. Of all the participants, tobacco users were 29(3.6%), diabetics
60 (7.5%), alcoholic users 99 (12.5%) and more than half were overweight/obese.
The prevalence of Systolic Hypertension was 65% and Diastolic Hypertension was
50% Few participants 85 (11%) had chest pain, 56 (7%) had tachycardia and
difficulty in breathing 45 (6%). By ECHO diagnosis; the prevalence of dilated
cardiomyopathy was 3.8%, hypertensive heart diseases 2.3% and valvular heart
diseases was 2%. Majority 780 (99%) and 694 (88%) had normal Left Ventricular
Systolic and Diastolic functions respectively. Furthermore, by ECG diagnosis, the
prevalence of Left Ventricular Hypertrophy was 8% and ischemic heart disease was
diagnosed in 4% of the participants. In a multivariate analysis, CVD were found to
be statistically significant associated with the age 65+ years, 3.41 [95% CI 1.49 -
7.78, p- value 0.004], diastolic blood pressure above or equal to 90 mmHg, 1.61
[95% CI 1.05 -2.48, p -value 0.03] and overweight/ obese 1.94 [95% CI 1.28 -2.92, p- value 0.002]. Conclusion: The prevalence of cardiovascular diseases was found to
be high and the main associated risk factors were advanced age, overweight/obese
and diastolic hypertension. Some of the participants had already developed
asymptomatic structural heart disease and features which were suggesting of
coronary artery diseases.
BACKGROUND
Cardiovascular disease (CVD) is the group of diseases which includes structural heart diseases,
coronary artery disease and all diseases of the blood vessels in the brain and other peripheral
circulatory systems of the human. In 2016, World Health Organization (WHO) reported that
CVD kills more than 17.9 million people annually all over the continents, representing 31% of
all deaths(1). Low and middle income countries are more affected and about 80% of all death
are due to acute/chronic coronary syndromes and cerebrovascular events such as stroke (2–
5). Young and middle aged individuals die of CVD and therefore WHO and World Heart
Federation (WHF) are working together to reducer these mortalities by 25% by 2025/30 in all
countries (5,6).
The risk factor for cardiovascular diseases such as diabetes and overweight/obesity begins
early in childhood and adolescents The earlier manifestations of these risk factors predicts the
earlier increase of asymptomatic CVDs younger adults (7,8). The children /adolescents remains
asymptomatic but the evidence from the autopsy and land marks trial showed the existence of
subclinical conditions at the age of 22 years old (9). Among those who died at an age of 18 years
without diabetes mellitus, autopsy studies found a close relationship of aortic fatty streaks with
an increased level of total cholesterol and low-density lipoprotein cholesterol (LDL-c)(10).
Coronary artery diseases begin early in childhood/adolescents and the individual remains
subclinical. One study which involved 2,876 participants aged between 15 and 34 years old
found atherosclerotic lesions in coronary arteries (11). The main pathology of CVD is the
asymptomatic gradual onset of atherosclerosis which begins early in life time. The symptoms
and complications are overt as an individual becomes older (12,13).
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 2, April-2022
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In United State of America (USA) CVDS is the leading cause of morbidity and mortality and
about 40 million individuals over the age of 65 are affected (14,15). Morbidity and Mortality
rates increases with age, for instance individuals with age of 80 years the prevalence is above
80% (15).
In the Sub-Saharan Africa countries where majority of the people lives in rural areas the trends
of risk factors for cardiovascular diseases are increasing, however with variations among
countries.
In Mozambique, about 64% of the population lives in rural areas. In this country, the prevalence
of adults with obese (BMI of ≥30 kg/m2) is 9.7% which is less than that reported globally
(13.1%) (16). The prevalence of Rheumatic Heart Diseases (RHD) is 3.04% which is also higher
than that which was reported globally (0.53%) and the mortality rates attributable by RHD is
0.16%(16). Furthermore, the rates of tobacco use among adults is 23% males , 3% females ,
hypertension 31%, diabetes 7.4% (16). In this low income country, cardiovascular mortality
rate is about 11.62% (16).
The aim of this study was to determine Prevalence of Cardiovascular Diseases and associated
factors among patients who came to attend JKCI mobile clinic in South Western urban Tanzania.
Also, the study aimed at creating the database for the risk factors of CVDs in South West urban
settings. The results of this study will help the policymakers to propagate the current
preventive measures for CVDs.
METHODOLOGY
Study design
A cross-sectional community-based study
Study population
785 consenting adults were consecutively recruited, who came to attend JKCI mobile Clinic at
Songea Regional Referral Hospital in South West urban Tanzania in 2018.
Study tools
12 lead Electrocardiogram and a 2D, M mode Transthoracic Echocardiogram were used to
determine the structural and none structural heart changes from the participants. A structured
questionnaire was used to obtain and gather comorbid information such as record blood
pressure, Body weight/BMI and fasting / random blood sugar. BP was checked while the
patient was sitting on the chair with their feet kept flat on the floor a. Three readings were
obtained at the interval of three minutes when the first was high for those who were not
previously diagnosed with hypertension. The average of the last two reading was calculated to
determine the final diagnosis of hypertension. The statistical analysis was done using IBM SPSS
Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp, U.S.A
Ethical Consideration
The ethical clearance was obtained from Jakaya Kikwete Cardiac Institute Review Board and
from the management of Songea Regional Referral Hospital. A comprehensive informed
consent form was signed by the participant or a close relative of a participant. The issue of
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
autonomy, beneficence were explained in the form in a language that the patient understood.
This clinical study was conducted according to the revised declaration of Helsinki concerning
biomedical research in using patient information. All authors agreed for this manuscript to be
published.
RESULTS
Table 1: Socio-demographic characteristics of study participants, n=785
Characteristic Frequency Percent
Sex
Males 257 32.7
Females 528 67.3
Age (Years)
18-39 110 14.0
40-64 479 61.0
65+ 196 25.0
Mean (SD) 55.5 (14.4)
Level of education
Never went to school 26 3.3
Primary school 409 52.1
Secondary school 274 34.9
Higher education 76 9.7
Marital status
Single 66 8.4
Married 558 71.1
Widowed 121 15.4
Divorced 5 0.6
Separated 35 8.4
Occupation
Employed 325 41.4
Non-employed 460 58.6
Sponsor
NHIF 625 79.6
Self 156 19.9
Other Insurance 4 0.5
Of 785 participants, 528 (67.3 %) were females, 479 (61%) were middle aged (40-60 years)
and 196 (25%) were 65 years old and above, mean (SD) age for all participants was 56 (14)
years. In terms of level of education, majority 409 (52.1%) had primary education. Most of
participants were married 558 (71%), unemployed 460 (58.6%) and 625 (80%) were
sponsored by National Health Insurance Fund (NHIF) for treatment.
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 2, April-2022
Services for Science and Education – United Kingdom
Table 2: Univariate analysis on risk factors for cardiovascular disease (CVD) among study
participants n=785
Factor Frequency Percent
Systolic blood Pressure (mmHg)
Normal (<140) 274 34.9
High (140+) 511 65.1
Mean (SD) 151.7 (27.0)
Diastolic blood pressure (mmHg)
Normal (<90) 395 50.3
High (90+) 390 49.7
Mean (SD) 89.8 (15.4)
BMI
Under weight 7 0.9
Normal 358 45.6
Overweight /Obese 420 53.5
Mean (SD) 26.4 (6.6)
Alcohol consumption
Consume 99 12.6
Not consume 686 87.4
Diabetes status
Diabetic 60 7.6
Not diabetic 725 92.4
History of smoking
Smoked/smoking 29 3.7
Never smoker 754 96.3
Of all participants, tobacco users were 29 (3.6%), diabetics 60 (7.5%), alcoholics 99 (12.5%)
and more than half were overweight/obese. The prevalence of Systolic Hypertension (SBP 140+
mmHg) was 65% and Diastolic Hypertension was 50% (DBP 90+ mmHg).
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
Table 3: Clinical symptoms of CVD reported by study participants, n=785
Symptom Frequency Percent
Heart rate (Beats per minute)
Bradycardia (<60) 75 9.6
Normal (60-100) 654 83.3
Tachycardia (>100) 56 7.1
Mean (SD) 77.1 (16.1)
Chest pain
Yes 85 10.8
No 700 89.2
Difficulty in breathing
Yes 45 5.7
No 740 94.3
Palpitation
Yes 44 5.6
No 741 94.4
Tender liver
Yes 4 0.5
No 781 99.5
Elevated Jugural Venus Pressure
Yes 2 0.3
No 783 99.7
Leg swelling
Yes 17 2.2
No 768 97.8
Assessment of clinical symptoms of participants reveal that, eighty-five (11%) participants had
chest pain, 56 (7%) had tachycardia and 45 (6%) had difficulty in breathing. Forty-four (5.6%)
participants presented with palpitation, 4 (0.5%) with tender liver, 17 (2.2%) with leg swelling
and 2 (0.3%) with elevated Jugular Venous Pressure (elevated JVP). By ECHO diagnosis, the
prevalence of dilated cardiomyopathy was 3.8%, hypertensive heart diseases 2.3% and
valvular heart diseases was 2%. Majority 780 (99%) and 694 (88%) had normal Left
Ventricular Systolic and Diastolic functions respectively. Furthermore, by ECG diagnosis, 9
(1.2%) presented with Arrhythmias, the prevalence of Left Ventricular Hypertrophy was 8%,
Right Ventricular Hypertrophy was 0.5% and ischemic heart disease was 4%.
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 2, April-2022
Services for Science and Education – United Kingdom
Table 4: ECG diagnosis n=785
Factor Frequency Percent
Arrythmias
Yes 9 1.2
No 776 98.8
Left Ventricular Hypertrophy
Yes 65 8.3
No 720 91.7
Right Ventricular Hypertrophy
Yes 4 0.5
No 781 99.5
Ischemic heart disease
Yes 34 4.3
No 751 95.7
Others
Yes 8 1.0
No 777 99.0
**others include: RBBB, LBBB and heart block
Table 5: Echo diagnosis n=785
Factor Frequency Percent
Dilated cardiomyopathy
Yes 30 3.8
No 755 96.2
Left Ventricular systolic function
Preserved (LVEF ≥ 40%) 780 99.4
Impaired (LVEF < 40%) 5 0.6
Left Ventricular diastolic function
Preserved 694 88.4
Impaired 91 11.6
Ischemic heart disease
Yes 15 1.9
No 770 98.1
Hypertensive heart disease
Yes 18 2.3
No 767 97.7
Valvular heart disease
Yes 16 2.0
No 769 98.0
Other diagnosis
Yes 3 0.4
No 782 99.6
**Others include; congenital heart disease, effusion (pericardial), constrictive pericardial and
infective endocarditis
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
Table 6: Association between sex and modifiable risk factors for cardio vascular disease, n=785
Factor Sex P-value
Total Male n=257
n (%)
Female n=528
n (%)
Systolic blood
Pressure (mmHg)
Normal (<140) 265 (33.8) 87 (33.9) 178 (33.7) 0.969
High (140+) 520 (66.3) 170 (66.2) 350 (66.3)
Diastolic blood
pressure (mmHg)
Normal (<90) 380 (48.4) 126 (49.0) 254 (48.1) 0.809
High (90+) 405 (51.6) 131 (51.0) 274 (51.9)
BMI
Under weight 7 (0.9) 3 (1.2) 4 (0.8) <0.001
Normal 358 (45.6) 143 (55.6) 215 (40.7)
Overweight
/obese
420 (53.5) 111 (43.2) 309 (58.5)
Alcohol use
Consume 97 (12.5) 45 (17.6) 52 (9.9) 0.002
Not consume 682 (87.6) 211 (82.4) 471 (90.1)
Diabetes status
Diabetic 50 (7.5) 18 (8.5) 32 (7.1) 0.542
Not diabetic 613 (92.5) 195 (91.6) 418 (92.9)
smoking
Smoked/smoking 28 (3.6) 14 (5.5) 14 (2.7) 0.047
Never smoker 754 (96.4) 242 (94.5) 512 (97.3)
The associations between sex and modifiable risk factors for CVD were examined, in terms of
BMI, a significant difference (p-value<0.001) between males and females was observed
whereby overweight/obese females were 58.5% while males were 43.2%. Male alcohol
consumers were 17.6% while females were 9.9% with a statistical significance difference (p- value=0.002) between them, even in tobacco using habits more males (5.5%) than females (2.7)
were using tobacco and the difference was statistically significant (p-value=0.047).
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 2, April-2022
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Table 7: Association between Age and modifiable risk factors for Cardio Vascular Disease,
n=785
Factor Age Group P-value
Total 18-39 n=110
n (%)
40- 64 n=479
n (%)
65+
n (%)
Systolic blood
Pressure
(mmHg)
Normal (<140) 265 (33.8) 63 (57.3) 159 (33.2) 43 (21.9) <0.001
High (140+) 520 (66.2) 47 (42.7) 320 (66.8) 153 (78.1)
Diastolic blood
pressure (mmHg)
Normal (<90) 380 (48.4) 65 (59.1) 219 (45.7) 96 (49.0) 0.04
High (90+) 405 (51.6) 45 (40.9) 260 (54.3) 100 (51.0)
BMI
Under weight 7 (0.9) 2 (1.8) 1 (0.2) 4 (2.0) 0.007
Normal 358 (45.6) 61 (55.5) 205 (42.8) 92 (46.9)
Overweight/obese
420 (53.5) 47 (42.7) 273 (57.0) 100 (51.0)
Alcohol use
Consume 97 (12.5) 10 (9.1) 65 (13.7) 22 (11.2) 0.344
Not consume 682 (87.6) 100 (90.9) 408 (86.3) 174 (88.8)
Diabetes status
Diabetic 50 (7.5) 2 (2.0) 34 (8.5) 14 (8.5) 0.075
Not diabetic 613 (92.5) 98 (98.0) 364 (91.5) 151 (91.5)
Smoking
Smoked/smoking 28 (3.6) 3 (2.7) 16 (3.4) 9 (4.6) 0.644
Never smoker 754 (96.4) 107 (97.3) 460 (96.6) 187 (95.4)
The association between age and modifiable risk factors for CVD were examined, 65 years and
above individuals recorded relatively higher (66.8%) systolic blood pressure compared to
other age groups [18-39years (42.7%) and 40- 64 (66.8), p-value<0.001], in terms of diastolic
blood pressure, those with 40- 64 years recorded higher (54.3%) than other groups [18-39
(40.9%) and 65+ (51.0%), p-value=0.040] in terms of BMI, individuals with 40- 64 years
recorded higher (57.0%) than other groups [18-39 (47.2%) and 65+ (51.0%), p-value=0.007].
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
Table 8: Bivariate analysis to assess risk factors for cardiovascular disease (CVD) among study
participants
Factor Total With CVD
n=192
n (%)
Without CVD
n=593
n (%)
P-value
Sex
Males 257 (32.7) 63 (32.8) 194 (32.7) 0.98
Females 528 (67.3) 129 (67.2) 399 (67.3)
Age
18-39 110 (14.0) 13 (6.8) 97 (16.4) <0.001
40-64 479 (61.0) 106 (55.2) 373 (62.9)
65+ 196 (25.0) 73 (38.0) 123 (20.7)
Level of education
Never went to
school/primary education
435 (55.4) 121 (63.0) 314 (53.0) 0.047
Secondary school 274 (34.9) 57 (29.7) 217 (36.6)
Higher education 76 (9.7) 14 (7.3) 62 (10.5)
Marital status
Single 66 (8.4) 8 (4.2) 58 (9.8) 0.051
Married 558 (71.1) 142 (74.0) 416 (70.2)
Living alone (but had
partner before)
161 (20.5) 42 (21.9) 119 (20.1)
Occupation
Employed 325 (41.4) 63 (32.8) 262 (44.2) 0.005
Non-employed 460 (58.6) 129 (67.2) 331 (55.8)
Systolic blood Pressure
(mmHg)
Normal (<140) 265 (33.8) 48 (25.0) 217 (36.6) 0.003
High (140+) 520 (66.2) 144 (75.0) 376 (63.4)
Diastolic blood pressure
(mmHg)
Normal (<90) 380 (48.4) 70 (36.5) 310 (52.3) <0.001
High (90+) 405 (51.6) 122 (63.5) 283 (47.7)
BMI
Under weight 7 (0.9) 3 (1.6) 4 (0.7) 0.034
Normal 358 (45.6) 73 (38.0) 285 (48.1)
Overweight/Obese 420 (53.5) 116 (60.4) 304 (51.3)
Alcohol use
Consume 97 (12.5) 21 (11.1) 76 (12.9) 0.502
Not consume 682 (87.6) 169 (89.0) 513 (87.1)
Diabetes status
Diabetic 50 (7.5) 14 (10.0) 36 (6.9) 0.215
Not diabetic 613 (92.5) 126 (90.0) 487 (93.1)
Smoking
Smoked/smoking 28 (3.6) 12 (6.3) 16 (2.7) 0.021
Never smoker 754 (96.4) 179 (93.7) 575 (97.3)
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Table 9: Multivariate analysis to assess associated risk factors for Cardio-Vascular Disease
(CVD) among study participants
Factor Total With CVD cOR (95%CI) P- Value
aOR (95%CI) P-Value
Age
18-39 110
(14.0)
13 (11.8) Ref Ref
40-64 479
(61.0)
106 (22.1) 2.12 (1.14 -3.93) 0.017 1.56 (0.72 -3.38) 0.262
65+ 196
(25.0)
73 (37.2) 4.43 (2.32 -8.46) <0.001 3.41 (1.49 -7.78) 0.004
Level of education
Never went to
school/primary education
435
(55.4)
121 (27.8) 1.71 (0.92 – 3.16) 0.089 1.92 (0.79-4.66) 0.151
Secondary school 274
(34.9)
57 (20.8) 1.16 (0.61-2.22) 0.648 1.55 (0.64 -3.76) 0.332
Higher education 76 (9.7) 14 (18.4) Ref Ref
Marital status
Single 66 (8.4) 8 (12.1) Ref
Married 558
(71.1)
142 (25.5) 2.47 (1.15 -5.31) 0.02 1.59 (0.67-3.78) 0.294
Living alone (but had
partner before)
161
(20.5)
42 (26.1) 2.56 (1.13 -5.80) 0.024 1.17 (0.45-3.06) 0.748
Occupation
Employed 325
(41.4)
63 (19.4) Ref Ref
Non-employed 460
(58.6)
129 (28.0) 1.62 (1.15 -2.28) 0.006 1.20 (0.75 -1.91) 0.448
Systolic blood Pressure
(mmHg)
Normal (<140) 265
(33.8)
48 (18.1) Ref Ref
High (140+) 520
(66.2)
144 (27.7) 1.73 (1.20- 2.50) 0.003 1.52 (0.93 -2.52) 0.099
Diastolic blood pressure
(mmHg)
Normal (<90) 380
(48.4)
70 (36.5) Ref Ref
High (90+) 405
(51.6)
122 (63.5) 1.91 (1.37 -2.67) <0.001 1.61 (1.05 -2.48) 0.03
BMI
Under weight 7 (0.9) 3 (42.9) 2.93 (0.64 -13.37) 0.166 1.00(0.08-
13.28)
0.999
Normal 358
(45.6)
73 (20.4) Ref Ref
Overweight/Obese 420
(53.5)
116 (27.6) 1.49 (1.07-20.8) 0.019 1.94 (1.28 -2.92) 0.002
Diabetes status
Diabetic 50 (7.5) 14 (28.0) 1.50 (0.79-2.87) 0.217 1.29 (0.65-2.55) 0.46
Not diabetic 613
(92.5)
126 (20.6) Ref Ref
Smoking
Smoked/smoking 28 (3.6) 12 (42.9) 2.41 (1.12 - 5.19) 0.025 2.15 (0.79 -5.84) 0.132
Never smoker 754
(96.4)
179 (23.7) Ref Ref
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
In a multivariate analysis, CVD was found to be statistically significant associated with the age
65+ years, 3.41 [95% CI 1.49 -7.78, p- value 0.004], diastolic blood pressure above or equal to
90 mmHg, 1.61 [95% CI 1.05 -2.48, p -value 0.03] and overweight/ obese 1.94 [95% CI 1.28 -
2.92, p-value 0.002], while level of education, marital status, occupation systolic blood pressure,
diabetes and smoking/history of smoking showed no association with CVD.
DISCUSSION
A total of 785 participants were studied to determine the prevalence of cardiovascular diseases,
clinical presentation risk and associated factors. More than half of the participants were
females. The modifiable risk factors for cardiovascular disease that were found were diabetes
mellitus, hypertension, smoking/tobacco use and overweight/obese. Cardiovascular diseases
were statistically significant associated with old age, diastolic hypertension and overweight/
obese. Majority of the patients were able to pay for their treatment through the National Health
Insurance (NHIF).
Old age as a none modifiable risk factor for CVD
With regard to our study, old age was defined as the age of 65 years or above. Of all the
participants, 25% were old age. In a multivariate analysis, this age was statistically significant
associated with the occurrence of structural heart changes, 3.41 [95% CI 1.49 -7.78, p- value
0.004]. The results were keeping with the existing results from the prior studies which found a
strong association between the advanced age and cardiovascular diseases(17). However,
advanced age is confounded by other risk factors such as diabetes and obesity that tends to
occur with aging process and thus increases the likelihood of the progress of cardiovascular
disease(17).
Modifiable risk factors for cardiovascular disease
The modifiable risk factors for the development of cardiovascular diseases which were found
in our study were smoking/tobacco use, diabetic mellitus, alcohol use, overweight/obesity and
elevated systolic and diastolic blood pressures. Most of these are risk behaviors that can be
prevented through a combined effort of all stakeholders (Multidisciplinary approach).
Tobacco using habits
The tobacco using habits was determined in 3.6% of all participants. This rate is lower than that
which was reported from the general population. According to TDHS 2015/16 the prevalence
of tobacco use among adults in Tanzania was 14.1%(18–20). Also the rates of tobacco use
among adults which was reported by the National STEP survey in 2012 was 15.9% in 2012 and
by Kapito-Tembo was 21%(21,22). The differences can be explained by variation in sample
size, socioeconomic influences and the setting of the study. Our study was done in a hospital
setting among individuals who came for a healthy check and some of them had an underlying
cardiovascular disease. The lower rate which was reported by our study may also be explained
by the social transformation in the community. in the years 2012 above the rate of tobacco use
was high but the trend shows a decline in this risk behavior in the general population.
Tobacco using habits was statistically significant more in males (5.5%) than females (2.7%), p- value=0.047. The results are similar to other studies (TDHS 2015/16) which reported a high
rate of tobacco use in males (29%) than in females(2.9%) (1,23). Other studies which was done
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in Tanga city and Simanjiro Massai area also reported a high rate of tobacco use in males(2-
23%) than females(1-4%)(24,25). Tobacco use is one the main risk factors for coronary artery
disease (CAD). This unhealth behaviors among men can partly explain the documented
increasing rates of CAD in men as compared to females(26–28).
Former cross-sectional studies indicated the burden of tobacco use by zones, for example, the
high rate of tobacco use was reported in the Southern zone (31%) while the lower rate being
reported in the Southern Highlands (12%) (29). Therefore, the low rate of tobacco use which
was reported by our study can be explained by the geographical location and socioeconomic
status of the study participants.
Tobacco use is associated CVDs and other chronic illnesses that lead to airway diseases like
pneumonia, Chronic Obstructive Pulmonary Diseases (Emphysema and Chronic bronchitis),
and lung cancer (1,28,30,31).
Prevalence of diabetes mellitus
In our study, the prevalence of diabetics was 7.5% as compared to 9% which was reported by
National Survey of 2012(21,23). The lower rate in our study can be influence by the sample size
and socio-economic variations among the study participants. Previously studies which was
conducted in the rural setting documented the prevalence of 2%. However the rate in the same
setting is increasing (21.7%) according to the recent studies (32,33). Therefore, the prevalence
of T2DM was higher than that which was reported initially in rural settings but lower than the
recent reported. The difference can be influenced by variations in the socioeconomic factors
among the rural and urban dwellings. Furthermore, we may speculate that, T2DM is still a
public health problem in both urban and rural areas.
Overweight/ obesity and cardiovascular diseases
The prevalence of overweight/obese among the study participants were more than half. The
results are similar to that which was reported in Tanga city, in which majority of the
participants who came for an health check were overweight and obese(24). Also our results are
analogous to the recent reported results from Arusha in which about 70% of health workers
were obese/overweight(34). In a multivariate analysis overweight/ obese 1.94 [95% CI 1.28 -
2.92, p-value 0.002] were statistically significant associated with the occurrence of CVDs. To
translate this into a clinical setting, it means that, weight reduction can strongly influence a
significant reduction in the burden of a CVDs.
Systolic and diastolic hypertension and cardiovascular disease
The prevalence of hypertension among the studied individual was about 65%. This rate was
similar to that which was recently reported (70%) at Jakaya Kikwete cardiac institutes
(unpublished). The comparations in these two different settings can be due to the fact that
majority of the attendee were sick looking for medical care. On the other hand, the prevalence
of hypertension is higher than that which was reported in Northern Tanzania (28%)(35). This
difference can be elaborated by socioeconomic factors and the setting of these two studies. In a
multivariate analysis, CVD was found to be statistically significant associated with a high
diastolic blood pressure, 1.61 [95% CI 1.05 -2.48, p -value 0.03]. This finding is similar to that
which was reported from the retrospective cohort study involving outpatients from Kaiser
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
Permanente Northern California (KPNC)(36). This study from the developed world concluded
that elevated systolic blood-pressure played a greater role on the cardiovascular outcomes, but
in a sub group analysis, both systolic and diastolic hypertension were independently associated
with adverse cardiovascular events (37).
Clinical symptoms and signs
The results of this study indicated that few of the participants had symptoms or signs for
cardiovascular disease while the majority were asymptomatic. This may indicate an early stage
of the disease, stage A of CVD or they are compensated for the disease. However, the results of
this study found that the participants had chest pain were (11%), tachycardia (7%), difficulty
in breathing (6%), palpitations (5.6%) and tender hepatomegaly (2.2%). Also, the results of this
study showed that very few of the participants had overt symptoms for heart failure such as
lower limb edema (0.3%) and an increased jugular venous pressure (0.3%). The rate of
symptoms and signs for CVDs differs from that reported from a large Primary Care Population
in 31 countries of Central and Northeastern Pennsylvania between 2001 and 2010. By using
the Geisinger Health System, the rates of raised Jugular venous pressures in among the patients
with preserved Left ventricular systolic function (LVEF above 50%) were 19%, ankle edema
90%, tachycardia 11.6%, dyspnea in ordinary activity 90% and hepatomegaly 7%(38). The
difference may be attributed by the sociodemographic features of the participants, sample size
and study design.
Prevalence of Cardiovascular Diseases by Electrocardiogram and Echocardiogram
Resting 12 Lead Electrocardiograms (ECG)
Structural heart diseases and arrhythmias were diagnosed among the participants by using a
12-lead resting electrocardiogram. The prevalence rates of ECG abnormalities were Left
Ventricular Hypertrophy (8%), arrhythmias (1.2 %.) strain pattern of Right Ventricular
hypertrophy (0.5%) and ischemic heart disease (4 %.) These rates were lower than that which
was found among elderly population in USA. In this elderly population, 8.7% had ventricular
conduction defects, 5.3% first degree atrioventricular block and 3.2% atrial fibrillation. Our
study indicates a higher prevalent rate of left ventricular hypertrophy (8%) as compared to
4.2% which was found in USA among the elderly population (39). The high rate of left
ventricular hypertrophy in our study is reflecting the high rate of hypertension.
The rate of Left ventricular hypertrophy (8%) which was diagnosed by 12 lead ECG in our study
is lower as compare to (32%) which was found in Tanga city. Tanga is the big city compared to
Songea and it well known that the burden of CVDs is more in cities than in semiurban
areas(40,41). However, this rate is almost equivalent to that which was documented in USA
among the patients with hypertension (6.7%) (42).
Our study shown that, majority of the participants were hypertensive (SBP 63% and DBP 54%)
with lower rates of abnormal ECG finding as compared to another study that indicated higher
rates of abnormal ECG findings (31%) in patients with hypertension. This difference is
contributed by the young and middle age of our participants compared to older age of
counterpart study population. The prevalence of ECG abnormalities in a comparative study
were increasing with age, from 10.5% at age 65-69 years, to 20.2% by age 75-79 years, and
31.6% by age ≥85 (43). Our study indicated structural heart diseases among the study
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population and a high burden of hypertension. These two occurrences fuel each other for
development of symptomatic heart failure and increases mortality rates. (18,44).
The prevalence of cardiovascular disease by 2D, M mode Transthoracic Echocardiogram
(TTE)
The changes of the heart geometry appear earlier in asymptomatic patients with a diagnosis of
CVDs. These geometric changes can be detected early by the aid of an echocardiogram.
Structural heart changes which were noted in the study participants were dilated
cardiomyopathy (3.8%), hypertensive heart diseases (2.3%) and valvular heart diseases (2%).
Left ventricular systolic and diastolic dysfunctions were also prevalent in minority of the
partakers at the rates of 0.6% and 11.6% respectively.
The rates structural heart changes are lower than which was found among residents in Tanga
city. The rates of geometric changes of the heart which were found among the residents of
Tanga were left ventricular hypertrophy which indicates hypertensive heart disease (29%) and
mitral valve (valvular heart disease) regurgitation (10%)(24). The different in rates of
echocardiographic diagnosis can be explained by differences in socio demographic factors,
sample size of the study population and the underlying comorbidities. The rates of structural
heart changes are lower than that which was reported in a Supper Specialize Hospital in Dare
es salaam. The predominant cardiovascular diseases which were reported in this tertiary
hospital by echocardiogram were cardiomyopathy (28%), rheumatic heart disease/valvular
heart disease (12%) and ischemic heart diseases (9%) (45). Our study was done at a Referral
Regional Hospital which receives patients with stage A heart diseases from the local region
compared to a Supers Specialized Hospital which receives patients with high stages of heart
diseases from all regional referral hospitals in the country.
CONCLUSION
The prevalence of cardiovascular diseases was found to be high and the main associated risk
factors were overage, overweight/obese, and diastolic hypertension. Some of the participants
had already developed asymptomatic structural heart diseases and few had features which
were suggesting of coronary artery diseases, arrhythmias and heart failure.
ACKNOWLEDGEMENTS
We thank the Staffs and management of Songea Regional Referral Hospital for granting
permission to conduct this study. And we thank all patients who participated in the study
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Rweyemamu, S. J., Waane, T., Longopa, G. L., Kisenge, P. R., Bishashara, S., Mpella, R., & Mutagaywa, R. (2022). Prevalence of Cardiovascular
Diseases and Associated Factors Among Patients in Low- and Middle-Income Settings. European Journal of Applied Sciences, 10(2). 362-379.
URL: http://dx.doi.org/10.14738/aivp.102.11899
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