European Journal of Cardiovascular Medicine

Hypertension is a major public health problem worldwide.Hypertension is a disease that affects about one billion individual’s worldwide.1The prevalence of hypertension in India according to WHO estimates in people above 18 yrs is around 24%.2Essential hypertension produces proteinuria and a significant reduction in renal function in 5–15% of patients.3 Hypertension is also an independent predisposing factor for heart failure, coronary artery disease, stroke and peripheral arterial disease (PAD).4

Microalbuminuria (MA), defined as urinary albumin excretion (UAE) in the range of 30–300 mg/24 h, is seen in patients with established essential hypertension.5 Detection of increased UAE could be the best index of an increased global cardiovascular risk in a given patient.6

Micro-albuminuria (MA) is one of the earliest indications of kidney injury in patients with diabetes mellitus and hypertension and is associated with high incidence of cardiovascular morbidity.7 Micro-albuminuria possibly reflects a state of increased renal endothelial permeability and is considered an early marker of diffuse endothelial dysfunction.8 Micro-albuminuria is the excretion in urineof small quantities of albumin, insufficient to be demonstrated by ordinary laboratory methods. It has been suggested that micro-albuminuria may represent the renal manifestation of generalized, genetically conditioned vascular endothelial dysfunction.9,10

Although several studies have attempted to define the prevalence of microalbuminuria in essential hypertension, the exact figure is still unclear. The published prevalence of microalbuminuria in hypertensive subjects ranges from 4.7% to 58.4%.10,11

Since micro-albuminuria is associated with poor control of hypertension, its presence may indicate the need for improvement in control of hypertension and careful follow-up for detection of complications. This study has been undertaken with the concept of detecting micro-albuminuria, as the early marker of intra renal vascular dysfunction in essential hypertension

AIM AND OBJECTIVES:

1. To find out the prevalence of microalbuminuria in essential hypertensives.
2. To find out the correlates of microalbuminuria in patients with essential hypertension.

A hospital based Analytical Cross-sectional study was conducted at Narayana Medical college, Nellore among 100 randomly selected patients who were diagnosed with essential hypertension for a period of 6 months.

Sample size was calculated taking an estimated prevalence of 44% from previous study on Prevalence of Microalbuminuria in Patients of Essential Hypertension with 95% Confidence Interval and absolute precision of 10% the calculated sample size was 98.5 and it was rounded to 100.

Inclusion criteria

1.      Age group of 30-70 years.

2.      All new and old casesof hypertension (as per JNC-VII guidelines)

3.      Those who give consent for the study.

Exclusion criteria

1.      Pregnant women

2.      Chronic heart failure and Hepatic and renal insufficiency.

3.      Patients with secondary hypertension.

Microalbuminuria is defined as urinary albumin excretion in range of 30–300 mg/24 hr, and was measured by hemocue albumin technique.

From the study subjects demographic data, cardiovascular history, and other factors was collected using a semi structured questionnaire. The following measurements were then carried out on each patient: Urinary albumin and cholesterol, left ventricular hypertrophy BY 2D-echo and blood pressure measurement.

Statistical Analysis: Data collected was entered in MS-Excel 2013 and was analysed using SPSS version 23 software (trail version) and p-value less than 0.05 was considered statistically significant. Chi-square test (Fischer’s exact test wherever applicable) and Unpaired t-test was used to find out the significant difference between groups and p-value less than 0.05 was considered statistically significant.

The age range of the present study was 34 to 69 years with mean age of 55.64 ± 11.76 years. Out of 100 study subjects 61 (61%) were male and 39 (39%) were female with male: female ratio of 1.56:1. The prevalence of microalbuminuria in the present study was 19%. The mean age of micro-albuminuric patients (52.42 ± 8.78) was less compared to nonmicro-albuminuric patients (56.74 ± 10.91)and no statistical significant association was found between them (p<0.05) as shown in table-1.

The prevalence of microalbuminuria was more in males 19.7% when compared to female 17.9% but no statistical significant association was found between them. Body Mass Index (BMI) was statistically higher (p<0.05) amongst the cases having micro-albumin in their urine as shown in table-1.

The duration of hypertension was high in microalbuminuria cases 5.47 ± 2.32 yrs when compared to non-microalbuminuria patients 3.52 ± 1.26 yrs and a statistically significant association was found  between them (p<0.05) as shown in table-2.

Diastolic blood pressure and cholesterollevels were found to be higher in cases of microalbuminuria when compared to normal patients and a statistically significant association was found between them (p<0.05). Left Ventricular Hypertrophy (LVH) was present in significant number of patients with MA as compared to those without MA (55.5% vs. 15.4%, P<0.05) as shown in table-2.

Table 1: Association between socio-demographic variables and microalbuminuria

Table 2: Association between clinical profile and microalbuminuria

Microalbuminuria was known to occur early in the course of essential hypertension. Hypertensive nephropathy is a known cause of chronic kidney disease but in many cases it may remain under recognized. In the present study out of 100 patients examined the prevalence of microalbuminuria was 19%. Various studies conducted to estimate the level of microalbuminuria in hypertensive patients found wide range of prevalence ie., from 23.2% in Tagore PK et al1, 47% in HK Aggarwal et al2, 67.83% in R Habbal et al3, 47% in Maxwell M. Nwegbu5 et al study and this may wide range of study settings and criteria for selecting patients.

The high prevalence of MA in patients with essential hypertension in this part of country must raise an alarm amongst the health professionals about the rising subclinical chronic kidney diseases (CKD). The prevalence of microalbuminuria was more in males 19.7% when compared to female 17.9% but no statistical significant association was found between them which was similar to the findings of some studies.4,13

In study by Hitha et al.,also, it was found that the prevalence of MA increased steadily in patients of hypertension with advancing age.16 In another large study of 11,343 nondiabetic hypertensive patients with a mean age of 57 years, MA was present in 32% of men and 28% of women and prevalence increased with age, severity, and duration of hypertension.17

The duration of hypertension was high in microalbuminuria cases 5.47 ± 2.32 yrs when compared to non-microalbuminuria patients 3.52 ± 1.26 yrs and a statistically significant association was found  between them (p<0.05). Various studies conducted on the prevalence of microalbuminuria had also found that a direct association ie., with increase in duration of hypertension the prevalence of microalbuminuria also increases.13,18

Body Mass Index (BMI) was statistically higher (p<0.05) amongst the cases having micro-albumin in their urinewhich supports the already proven fact that high BMI among hypertensives are at high risk of micro-albuminuria.There is a positive correlation between micro-albuminuria and obesity which was also found inHitha et al study .16

In the present study, LVH was present in significant number of patients with MA as compared to those without MA (55.5% vs. 15.4%, P = 0.003). Gatzka et al. studied 704 patients of essential hypertension and observed higher LVM in microalbuminuric patients than nonmicroalbuminuricpatients.19In a large study by Agrawal et al. of 11343 nondiabetic hypertensive patients, those with MA had a higher prevalence of LVH and other cardiovascular events as compared to those without MA.17

Our study demonstrates that the presence of MA in a significant number of essential hypertensioncases. The prevalence of micro-albuminuria increases with the increase in duration and level of blood pressure. Micro-albuminuria can be considered as a marker of adverse cardiovascular risk profile such as Left Ventricular Hypertrophy. We recommend that early screeningfor microalbuminuria in patients of essential hypertension and so that early initiation of treatment might help in reducing the morbidity and mortality.

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