Association of Selected Haematological, Biochemical and Genetic Biomarkers among Patients with Essential Hypertension at Chuka County Referral Hospital, Kenya

Abstract

Hypertension is one of the leading causes of heart disease such as coronary artery disease and heart failure along with stroke and kidney damage among other conditions. Known as the “silent killer", hypertension is largely an asymptomatic disease that becomes evident only when it progresses to severity and begins to cause tissue damage in multiple organs. A significant proportion of the general population is not aware of their hypertension status and are therefore not under management to prevent development of complications that are associated with severe untreated essential hypertension. It is approximated that in almost 90% of cases, the underlying causes of hypertension are unknown (perhaps genetic or other environmental factors) and accounts for majority of cases. Primary or essential hypertension (EH) is the name given to this condition. This is in contrast to secondary hypertension that is the result of known medical conditions. Multiple risk factors for hypertension include: age, level of physical activity and genetics. Early detection of essential hypertension is crucial to ensure measures are taken to mitigate against the devastating consequences. The purpose of the current study was therefore to determine whether there is an association between AGTR1 (rs5186) SNP, C - reactive protein, selected hematological biomarkers and EH in a Kenyan population. These markers would contribute to monitoring progression and effective control of essential hypertension. This was a case control study conducted from March to July, 2022 at Chuka County Referral Hospital, Kenya. This being a case-control experiment, comprised of age and gender matched normotensive blood donors as the controls and cases being hypertensive patients. The study included 136 cases and 136 controls. Study participants were recruited by convenience sampling using selection criteria to attain the sample size required. Blood samples were collected and biomarkers analyzed. DNA was extracted and analyzed by PCR and Restriction Fragment Length Polymorphism. Data analysis was performed using Statistical analysis system (SAS) software. Independent t-test and Mann Whitney U test were used to analyse continuous data while for the categorical data, fishers’ exact test and Odds ratio was calculated to determine association between the groups. P values less than 0.05 were considered as statistically significant. The results showed that mean values of mean platelet volume (MPV), Neutrophil to Lymphocyte ratio (NLR) and the median values of C-reactive protein (CRP) and Red Cell Distribution Width (RDW) were significantly higher in hypertensive group compared to healthy control group. Platelet Distribution Width (PDW) (p=0.52) was found not to be statistically significant. The results also indicated that the 98.6% of the study population had the wild type AA genotype, and 1.4% was AC heterozygous carriers of the A1166C polymorphism. The results showed that there was no statistically significant association between AGTR1 (rs5186) SNP frequency and EH in Tharaka Nithi County, Kenya. (p=0.6236, ORs=0.4952(95%CI: 0.0442-5.5456). Therefore, it is important for clinicians to be aware that these biomarkers could be elevated due to essential hypertension in the absence of other inflammatory and chronic diseases. Derangements in CRP, RDW, MPV and NLR can help clinicians question a likelihood of essential hypertension in undiagnosed cases. This can help in prompt initiation of management and control of the disease. This study also recommends that further research to investigate other possible mutations in other genes which could be associated with essential hypertrnsion in Kenyan population.