The spectrum and the effects of cardiovascular risk factors on the cardiac structure and function at Madadeni Provincial Hospital (Internal Medicine Department)

Abstract

Cardiovascular disease (CVD) is now a leading cause of death worldwide. According to the United Nations (UN), people who are above 60 years of age have a greater chance of developing CVD, and are projected to double in South Africa by 2050. There is clear evidence that patients with cardiovascular risk factors present with cardiac structural and functional abnormalities. Left ventricular remodelling is a major complication in patients with cardiovascular risk factors, particularly hypertension. Very few studies evaluating the structural and functional changes in response to CVD, and none, to the knowledge of the researcher, have been conducted on black Africans in South Africa in urban and rural areas Aim: The aim of the study was to determine the spectrum and the effects of cardiovascular risk factors on cardiac structure and function in patients presenting to Madadeni Provincial Hospital (Internal Medicine Department). Materials and method: The researcher systematically sampled 200 participants in the northern KwaZulu-Natal (KZN) region, presenting to Madadeni Provincial Hospital (Internal Medicine Department) and administered a questionnaire that collected their information on socio-demographic and cardiovascular risk factors. Other measurements included blood pressure, blood glucose, biochemical analysis and transthoracic echocardiography. The statistical analysis included descriptive statistics (frequency tables, bar and pie charts) and chi-squared and T tests to present the study findings and comparison between variables. A multinomial logistic regression analysis was performed to determine independent predictors for left ventricular geometry. Results: The mean age was 50.10 ± 16.188 (range: 18 – 79), with 114 (57.0%) females and 86 (43.0%) males. Black patients had the highest prevalence of cardiovascular risk factors (56, 87.0%), followed by Indians (27, 13.5%), whites (12, 6.0%) and mixed ancestry (5.4.0%). There was a high prevalence of modifiable cardiovascular risk factors with hypertension (HPT) being the leading factor (31.5%), followed by diabetes mellitus (17.0%). The prevalence of hypertension together with diabetes mellitus was 24.5%. Dyslipedemia was the lowest with 2.0%. The prevalence of left ventricular systolic function was normal in 174 (87.0%) participants and abnormal in 26 (13.0%). The prevalence of left ventricular diastolic dysfunction was 70.5% in women and 29.4% in men. There was a high prevalence of normal left ventricular geometry with 103 (51.5%), followed by concentric hypertrophy 72 (36.0%), eccentric remodelling 13 (6.5%), concentric remodelling 11 (5.5%), and eccentric hypertrophy with 0.5%. Metabolic syndrome was documented in 58.3% blacks, followed by 33.3% Indians and 8.3% whites. A multinomial logistic regression model was fitted with the dependent variable, which was left ventricle geometry. The independent variables were age, gender, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), HPT, diabetes mellitus and diastolic function. When comparing risk factors for concentric hypertrophy to the category ‘normal’, the significant variable was diastolic function (p value = 0.015). The risk factors for concentric remodelling was found to be SBP (p = 0.057) and BMI category morbid obese (p = 0.015). The risk factors for eccentric remodelling were found to be BMI category morbid obese (p = 0.002) and HPT (p = 0.016). Conclusion: The study has shown that there is a high prevalence of modifiable cardiovascular risk factors in the northern KZN region and many patients present with metabolic syndrome during the course of the disease. The study also revealed a high prevalence of left ventricular diastolic dysfunction and left ventricular geometric patterns in the studied population. The risk factors for left ventricular geometry were HPT, morbid obesity, diastolic function and SBP.