Background: Microalbuminuria serves as a critical early biomarker of hypertensive complications, preceding overt target organ dysfunction. This study evaluated microalbuminuria in essential hypertensive patients and its correlation with target organ damage. Methods: A cross-sectional study was conducted on 160 patients with essential hypertension at Sri Aurobindo Medical College. Patients underwent comprehensive evaluation including fundoscopy, echocardiography, renal ultrasonography, and biochemical analysis. Microalbuminuria was assessed using urinary albumin-creatinine ratio (UACR). Statistical analysis included descriptive statistics, Chi-square test, Pearson correlation using R software, one way ANOVA and Kruskal-Wallis Test. Results: The study comprised 100 males (62.5%) and 60 females (37.5%) with mean age 51.66±15.28 years. Grade 1 systolic hypertension was present in 96.3% patients. Target organ damage included retinopathy in 53.7%, left ventricular hypertrophy in 51.2%, and diastolic dysfunction in 61.9%. Mean UACR was 1373.37±2784.01 mg/g. Significant correlation was found between UACR and creatinine levels (rho=0.305, p<0.0001). Proteinuria showed significant association with elevated creatinine (p=0.016). Conclusions: Microalbuminuria demonstrates strong correlation with renal dysfunction markers in essential hypertension, supporting its role as an early indicator of target organ damage. Regular UACR screening is recommended for hypertensive patients, particularly those over 40 years.
Systemic hypertension represents a substantial global health challenge, serving as a principal contributor to cerebrovascular accidents, cardiac complications, chronic kidney disease, and increased mortality rates across diverse populations¹. The condition particularly burdens healthcare infrastructure in India, where urban prevalence has increased thirty-fold and rural prevalence ten-fold over recent decades². Contemporary epidemiological data reveals variable prevalence rates ranging from 6.2-36.4% in urban males and 2-39.4% in urban females, with rural populations showing rates of 3-36% and 5.8-37% respectively³.
Microalbuminuria, defined as urinary albumin excretion between 30-300 mg/24 hours or 20-199 µg/minute in timed collections, emerges as a critical early biomarker of hypertensive complications⁴. This subclinical manifestation precedes overt target organ dysfunction, including left ventricular hypertrophy, retinal changes, and cognitive impairment⁵. The prevalence of microalbuminuria varies considerably, affecting 10-40% of hypertensive diabetic patients and 5-7% of apparently healthy individuals⁶. As an independent cardiovascular risk predictor, microalbuminuria signifies endothelial dysfunction and warrants systematic evaluation in hypertensive management protocols⁷.
The present study aimed to evaluate hypertension severity in essential hypertensive patients, quantify microalbuminuria prevalence, assess comprehensive target organ involvement, and establish correlations between microalbuminuria levels and extent of target organ compromise
This cross-sectional study was conducted at the General Medicine Department of Sri Aurobindo Medical College and Post Graduate Institute to evaluate microalbuminuria presence in essential hypertensive patients and its association with target organ damage.
Patient Selection
Patients admitted to the General Medicine Department with essential hypertension fulfilling inclusion and exclusion criteria were recruited. Blood pressure was recorded using standard sphygmomanometer with two readings taken five minutes apart. The American College of Cardiology/American Heart Association classification was used for hypertension grading.
Inclusion Criteria:
Exclusion Criteria:
Sample Size Calculation
Sample size was calculated using the formula: N = Z₁²⁻ᴬ¹² P(1-P)/l²
A total of 160 patients fulfilling inclusion criteria were included based on yearly admission feasibility of over 100 patients with newly diagnosed or existing essential hypertension.
Data Collection and Investigations
Data were collected using pre-structured proforma. Early morning mid-stream urine samples were collected for microalbuminuria assessment. The following investigations were performed: Complete Blood Count, Urea and Serum Creatinine, Electrolytes (Sodium, Potassium, Chloride), Lipid Profile, Urine Routine Microscopy, Urine for Microalbumin, Fundus Examination, Ultrasonography Whole Abdomen, Electrocardiography and Echocardiography.
Statistical Analysis
Statistical analysis was conducted using R software. Data were presented using frequency tables with mean±standard deviation for quantitative variables and frequency with percentage for qualitative variables. Chi-square test was applied for associations between qualitative variables. Pearson correlation coefficient test evaluated relationships between quantitative variables. A p-value <0.05 was considered statistically significant. One way ANOVA and Kruskal-Wallis Test was used.
Ethical Considerations
Informed consent was obtained from all patients before enrolment. The study was conducted in accordance with ethical guidelines and institutional protocols.
The study comprised 160 participants with male predominance (100 males, 62.5% vs 60 females, 37.5%). The male-to-female ratio of 1.67:1 indicates significant gender disparity warranting consideration in cardiovascular and renal outcome interpretation. Mean participant age was 51.66±15.28 years, indicating predominantly middle-aged population with established cardiovascular risk. Average hypertension duration was 9.58±5.19 years, suggesting chronic disease with potential for target organ damage. Young hypertensives with onset less than 40 yrs of age were 38.8% (62 of 160).
Table 1. Distribution of Clinical Parameters Among Study Subjects
Parameter |
Value |
|
|
Male |
100 (62.5%) |
Female |
60 (37.5%) |
Age (years) |
51.66 ± 15.28 |
Young Hypertensives |
62 (38.75%) |
Hypertension duration (years) |
9.58 ± 5.19 |
Systolic BP (mmHg) |
143.88 ± 5.61 |
Diastolic BP (mmHg) |
83.75 ± 6.89 |
Hemoglobin (g/dL) |
10.68 ± 2.21 |
Total leukocyte count (/μL) |
4901.16 ± 6016.62 |
Platelet count (×10⁵/μL) |
5.10 ± 14.36 |
Urea (mg/dL) |
44.62 ± 28.29 |
Creatinine (mg/dL) |
1.05 ± 0.51 |
Sodium (mEq/L) |
136.51 ± 11.55 |
Potassium (mEq/L) |
4.17 ± 0.90 |
Chloride (mEq/L) |
103.43 ± 17.57 |
Total cholesterol (mg/dL) |
139.41 ± 69.79 |
HDL cholesterol (mg/dL) |
31.84 ± 12.68 |
Average systolic and diastolic blood pressures were 143.88 mmHg and 83.75 mmHg respectively, consistent with Grade 1 hypertension. Haemoglobin levels showed mild anemia (10.68 g/dL). The lipid profile demonstrated significant dyslipidaemia with markedly low HDL cholesterol (31.84 mg/dL) and elevated triglycerides (164.87 mg/dL). Proteinuria assessment revealed significant albuminuria with markedly elevated UACR (mean 1373.37 mg/g, SD 2784.01).
The vast majority of patients (96.3%) presented with Grade 1 systolic hypertension, while 74.4% had normal diastolic pressure. This discordance indicates isolated systolic hypertension, characteristic of middle-aged and elderly populations due to arterial stiffening.
Fundoscopic examination revealed normal findings in 46.3% of subjects, while 53.7% demonstrated varying degrees of hypertensive retinopathy, indicating significant hypertensive retinopathy and organ damage. Left ventricular hypertrophy was present in 51.2% of subjects, with mild LVH being most common (31.9%), reflecting chronic hemodynamic burden of hypertension on cardiac structure. Diastolic dysfunction was present in 61.9% of subjects, with Grade I being most prevalent (45.0%), suggesting early cardiac involvement with impaired relaxationStructural renal changes were minimal (1.3%) despite elevated UACR levels, suggesting functional rather than structural kidney disease. No statistically
significant differences were observed between blood pressure grades for renal parameters, suggesting that kidney damage may occur early in hypertension and may not correlate linearly with current blood pressure levels.
Table 3: Correlation of Echocardiographic findings and UACR
Echocardiographic Finding |
N (Patients) |
Mean UACR (mg/g) |
Std. Dev. |
|
|
MILD |
51 |
910.07 |
1971.08 |
|
|
MODERATE |
25 |
3619.08 |
4549.78 |
|
|
NORMAL |
78 |
1026.72 |
2238.47 |
|
|
SEVERE |
6 |
460.86 |
902.33 |
|
|
One-Way ANOVA (Parametric Test) to check whether the mean UACR differs significantly across the 4 echocardiographic categories was used with a p value of 0.00013. Since p < 0.05, the differences in mean UACR across echocardiographic.
Kruskal-Wallis Test (Non-Parametric Alternative) which compares the medians of UACR among the different categories was estimated to have a p-value: 0.00299. Which confirms the ANOVA result; the UACR distributions across echocardiographic groups differ significantly.
The investigation revealed demographic patterns regarding microalbuminuria prevalence across age groups. Participants exceeding 40 years demonstrated substantially higher microalbuminuria rates compared to younger cohorts⁸. This age-stratified distribution mirrors established patterns documented throughout Indian clinical populations⁹. Contemporary research has demonstrated similar findings among diabetic hypertensive patients, where individuals beyond 45 years exhibited microalbuminuria in 81.25% of cases¹⁰.
The relationship between advancing age and microalbuminuria prevalence appears particularly pronounced in hypertensive individuals with extended disease duration. Eastern Indian research has corroborated these observations, documenting microalbuminuria in 43.8% of type 2 diabetic patients with concurrent hypertension¹¹. These findings emphasize how chronological aging amplifies both renal and cardiovascular vulnerability within hypertensive populations.
The current investigation's findings regarding UACR levels across diastolic dysfunction grades revealed no statistically significant variations (p=0.958), contrasting with established literature documenting strong correlations between microalbuminuria and target organ damage¹². Previous Indian studies have demonstrated robust associations between microalbuminuria and left ventricular hypertrophy alongside hypertensive retinopathy¹³. Kerala-based research has similarly identified microalbuminuria as conferring elevated stroke risk and increased retinopathy likelihood¹⁴.
The divergent findings may reflect methodological variations, sample characteristics, or diagnostic threshold differences across studies. Research has identified strong positive correlations between UACR and both systolic and diastolic blood pressure¹⁵, suggesting that population-specific factors including comorbid conditions may modulate these relationships.
A statistically significant association emerged between proteinuria detection via dipstick methodology and elevated creatinine concentrations (p=0.016). This relationship aligns consistently with multiple Indian clinical investigations¹⁶. Research has demonstrated that protein-creatinine indices increase proportionally with hypertension severity and duration, exhibiting strong correlations with serum creatinine levels¹⁷.
The robust correlation between UACR and creatinine levels (rho=0.305, p<0.0001) identified in this investigation reinforces creatinine's reliability as an early renal damage biomarker within hypertensive populations. Contemporary research has established elevated systolic blood pressure as significant microalbuminuria predictor¹⁸.
The investigation's findings strongly support routine UACR screening implementation in hypertensive patients, particularly those exceeding 40 years or presenting with elevated creatinine levels. While UACR may not effectively stratify diastolic dysfunction severity, its association with creatinine underscores its utility in renal risk assessment protocols¹⁹. Clinical trial evidence has demonstrated that targeted antihypertensive therapy significantly reduces UACR in Indian hypertensive patients²⁰.
This comprehensive analysis provides significant insights into the intricate relationships between UACR, proteinuria, creatinine, and hypertension. The investigation established a robust positive correlation between UACR and creatinine levels (rho=0.305, p<0.0001), reinforcing UACR's effectiveness as a renal dysfunction marker in hypertensive individuals. The significant association between dipstick-detected proteinuria and elevated creatinine levels (p=0.016) suggests proteinuria's utility as an early kidney damage indicator. Furthermore, the correlation of UACR with LVH demonstrated by a p<0.0001, signifies the utility of UACR as a marker of hypertensive cardiac remodelling and end organ damage. The study findings corelate with the current literature available.
However, the absence of significant UACR differences across diastolic dysfunction grades and hypertension severity indicates that UACR alone may be insufficient for assessing disease progression. The study underscores regular renal function monitoring importance, particularly through UACR and proteinuria measurements, for early kidney dysfunction detection in hypertensive patients.
Key limitations include the cross-sectional study design preventing causal relationship establishment, single-center scope limiting generalizability, and limited biomarker assessment excluding other important indicators. Future investigations should adopt longitudinal approaches, incorporate multiple centers, and expand biomarker assessment for comprehensive understanding of hypertension pathophysiology.
World Health Organization. Hypertension. WHO Fact Sheet 2021. Available at: https://www.who.int/news-room/fact-sheets/detail/hypertension