Hypertension is one of the most prevalent non-communicable diseases worldwide and represents a major risk factor for cardiovascular morbidity and mortality. According to the World Health Organization, hypertension contributes significantly to the global burden of ischemic heart disease, stroke, chronic kidney disease, and heart failure. Persistent elevation of blood pressure leads to progressive structural and functional alterations in various organs, commonly referred to as target organ damage (TOD), affecting the heart, kidneys, brain, and vasculature. Importantly, these changes often remain clinically silent in the early stages, making early detection crucial for effective intervention and prevention of long-term complications.[1]

Microalbuminuria, defined as urinary albumin excretion between 30–300 mg/day, has emerged as a sensitive marker of generalized endothelial dysfunction and early renal involvement in hypertensive patients. It reflects increased vascular permeability and glomerular damage, serving as an early indicator of systemic microvascular injury. Several studies have demonstrated a strong association between microalbuminuria and increased cardiovascular risk, independent of traditional risk factors such as age, smoking, and dyslipidemia. Thus, microalbuminuria is now recognized not only as a renal marker but also as a surrogate marker of widespread vascular damage.[2]

Subclinical target organ damage refers to early pathological changes that precede overt clinical disease. These include left ventricular hypertrophy detected by echocardiography, increased carotid intima-media thickness assessed by ultrasonography, impaired renal function, and retinal microvascular changes. Identification of such subclinical abnormalities allows timely initiation of aggressive antihypertensive therapy and lifestyle modifications, thereby reducing future cardiovascular events. Among these, left ventricular hypertrophy is one of the most common cardiac manifestations of sustained hypertension and is associated with increased risk of arrhythmias, heart failure, and sudden cardiac death.[3]

The interrelationship between microalbuminuria and subclinical target organ damage highlights the systemic nature of hypertensive vascular injury. Evidence suggests that hypertensive patients with microalbuminuria are more likely to exhibit cardiac, renal, and vascular structural changes compared to those without microalbuminuria. This association underscores the role of microalbuminuria 

Source of Data

The study data were collected from patients diagnosed with essential hypertension attending the outpatient and inpatient departments of the tertiary care hospital during the study period. Clinical, laboratory, and imaging data were obtained after obtaining informed consent.

Study Design

This study was conducted as a hospital-based cross-sectional observational study.

Study Location

The study was carried out at the Department of General Medicine of a tertiary care teaching hospital.

Study Duration

The study was conducted over a period of 18 months from the date of institutional ethical committee approval.

Sample Size

A total of 200 patients diagnosed with essential hypertension were included in the study based on the inclusion and exclusion criteria.

Inclusion Criteria

• Patients aged ≥18 years diagnosed with essential hypertension
• Both male and female patients
• Patients willing to provide informed written consent
• Newly diagnosed and known hypertensive patients on treatment

Exclusion Criteria

• Patients with secondary hypertension
• Known diabetic patients
• Patients with chronic kidney disease
• Patients with overt proteinuria (>300 mg/day)
• Pregnant women
• Patients with acute infections or systemic inflammatory diseases
• Patients with known cardiovascular events such as myocardial infarction or stroke
• Patient with history of smoking or history of Alcohol consumption excluded

Procedure and Methodology

After obtaining informed consent, detailed demographic data, clinical history, and risk factor profile were recorded using a structured proforma. Blood pressure was measured using a standardized mercury sphygmomanometer after the patient had rested for at least 5 minutes in the sitting position. Two readings were taken at an interval of 5 minutes and the average value was considered for analysis.

All participants underwent routine biochemical investigations including fasting blood sugar, serum creatinine, lipid profile, and urine analysis. Microalbuminuria was assessed using a spot urine sample by calculating the urine albumin-to-creatinine ratio (UACR). Values between 30–300 mg/g were considered diagnostic of microalbuminuria.

Assessment of subclinical target organ damage included echocardiography to evaluate left ventricular mass index and detect left ventricular hypertrophy. Carotid Doppler ultrasonography was performed to measure carotid intima-media thickness. Fundoscopic examination was carried out to detect hypertensive retinopathy. Renal involvement was evaluated using estimated glomerular filtration rate (eGFR) calculated by the CKD-EPI formula.

Sample Processing

Venous blood samples were collected under aseptic precautions and processed in the central laboratory. Serum samples were analyzed using automated biochemistry analyzers. Spot urine samples were collected in sterile containers and analyzed for albumin and creatinine using immunoturbidimetric methods. Quality control measures were maintained throughout the laboratory procedures.

Statistical Methods

Data were entered into Microsoft Excel and analyzed using SPSS software version 25.0. Continuous variables were expressed as mean ± standard deviation and categorical variables were expressed as frequencies and percentages. Independent t-test was used to compare continuous variables between groups. Chi-square test was applied for categorical variables. Pearson correlation coefficient was used to assess the association between microalbuminuria and parameters of target organ damage. A p-value <0.05 was considered statistically significant.

Data Collection

Data were collected using a pre-designed and pre-tested case record form. Patient demographic details, clinical findings, laboratory reports, and imaging results were systematically recorded and verified before data entry. Confidentiality of patient information was maintained throughout the study period.

Table 1: Association Between Microalbuminuria and Subclinical Target Organ Damage (N = 200)

Table 1 demonstrates a strong and statistically significant association between microalbuminuria and various markers of subclinical target organ damage among essential hypertensive patients. The mean left ventricular mass index was significantly higher in patients with microalbuminuria (131.6 ± 14.9 g/m²) compared to those without microalbuminuria (114.3 ± 12.8 g/m²), with a mean difference of 14.2–20.5 g/m² and a highly significant p-value (<0.001). Similarly, carotid intima-media thickness was significantly increased in the microalbuminuria group (0.92 ± 0.13 mm) compared to the non-microalbuminuria group (0.78 ± 0.11 mm), indicating greater vascular remodeling (p <0.001). Renal function, as assessed by eGFR, was significantly lower among patients with microalbuminuria (74.8 ± 11.7 ml/min/1.73 m²) than those without microalbuminuria (86.2 ± 12.4 ml/min/1.73 m²), highlighting early renal impairment (p <0.001). Furthermore, the prevalence of left ventricular hypertrophy was markedly higher in the microalbuminuria group (67.5%) compared to the non-microalbuminuria group (33.3%), and hypertensive retinopathy was also more frequent in patients with microalbuminuria (57.8% vs 29.1%). Both associations were statistically significant (p <0.001).

Table 2: Prevalence of Microalbuminuria in Essential Hypertension (N = 200)

Table 2 shows that microalbuminuria was present in 83 out of 200 patients, resulting in an overall prevalence of 41.5% (95% CI: 34.7–48.4%), which was statistically significant (p <0.001). The mean urinary albumin-to-creatinine ratio of the study population was 48.9 ± 21.4 mg/g, reflecting moderate albumin excretion levels among affected individuals. Patients with microalbuminuria had a significantly longer duration of hypertension (7.4 ± 3.2 years) compared to those without microalbuminuria (4.9 ± 2.6 years), suggesting a progressive effect of chronic blood pressure elevation on renal microvascular damage (p <0.001). Additionally, systolic blood pressure levels were significantly higher in the microalbuminuria group (152.8 ± 12.6 mmHg) than in the non-microalbuminuria group (143.9 ± 11.8 mmHg), indicating poorer blood pressure control in patients with microalbuminuria (p <0.001).

Table 3: Presence of Subclinical Target Organ Damage in Essential Hypertension (N = 200)

Table 3 illustrates the burden of subclinical target organ damage among essential hypertensive patients. Left ventricular hypertrophy was detected in 47.5% of patients, while increased carotid intima-media thickness was observed in 36.0% of participants. Reduced renal function, defined as eGFR less than 90 ml/min/1.73 m², was present in 40.5% of patients, and hypertensive retinopathy was identified in 41.0% of cases. Overall, 60.5% of the study population exhibited at least one form of subclinical target organ damage. All parameters showed statistically significant prevalence (p <0.001), indicating a high burden of occult organ involvement even in the absence of overt clinical complications.

Table 4: Correlation Between Microalbuminuria and Subclinical Target Organ Damage Parameters (N = 200)

Table 4 presents the correlation analysis between urinary albumin-to-creatinine ratio and various parameters of subclinical target organ damage. A strong positive correlation was observed between UACR and left ventricular mass index (r = +0.62), indicating that increasing albuminuria was associated with greater cardiac hypertrophy. Similarly, UACR showed a moderate to strong positive correlation with carotid intima-media thickness (r = +0.58), reflecting progressive vascular remodeling with rising albumin excretion. A significant negative correlation was noted between UACR and eGFR (r = −0.55), demonstrating that higher levels of microalbuminuria were associated with declining renal function. Furthermore, positive correlations were observed between UACR and systolic blood pressure (r = +0.49) as well as duration of hypertension (r = +0.53), indicating that prolonged disease duration and poor blood pressure control contribute significantly to microvascular damage.

Association Between Microalbuminuria and Cardiac Target Organ Damage: In the present study, patients with microalbuminuria had significantly higher left ventricular mass index compared to those without microalbuminuria (131.6 ± 14.9 vs 114.3 ± 12.8 g/m², p <0.001), and the prevalence of left ventricular hypertrophy was markedly higher in the microalbuminuria group (67.5% vs 33.3%). Similar observations were reported by Bhowmick D et al. (2023)[5], who demonstrated a strong association between microalbuminuria and left ventricular hypertrophy in essential hypertension. Likewise, AR P. (2025)[2] reported significantly increased LV mass and concentric remodeling patterns in hypertensive patients with microalbuminuria. The HOPE substudy by Lamsal L et al. (2025)[3] further confirmed that microalbuminuria is independently associated with increased cardiovascular risk and structural heart disease, emphasizing its prognostic value.

Association With Vascular Changes (Carotid IMT): The present study found significantly higher carotid intima-media thickness in patients with microalbuminuria (0.92 ± 0.13 mm) compared to those without microalbuminuria (0.78 ± 0.11 mm), indicating accelerated atherosclerotic changes. These findings are consistent with the results of El Mokadem M et al. (2020)[4], who demonstrated that hypertensive patients with microalbuminuria had significantly thicker carotid walls and greater plaque burden. Similarly, Chen Z et al. (2024)[6] reported a strong relationship between albuminuria and carotid artery remodeling, suggesting that microalbuminuria reflects widespread vascular damage beyond renal involvement.

Renal Function and Microalbuminuria: In the present study, patients with microalbuminuria exhibited significantly lower eGFR values compared to those without microalbuminuria (74.8 ± 11.7 vs 86.2 ± 12.4 ml/min/1.73 m², p <0.001), indicating early renal impairment. This observation is supported by Chen Z et al. (2024)[6], who demonstrated that microalbuminuria is an early marker of hypertensive nephropathy and predicts progressive decline in renal function. Furthermore, Baqui MA et al. (2022)[7] reported that microalbuminuria was associated with faster deterioration of renal parameters and increased cardiovascular events in hypertensive populations.

Hypertensive Retinopathy and Microalbuminuria: The present study also demonstrated a significantly higher prevalence of hypertensive retinopathy in patients with microalbuminuria (57.8%) compared to those without microalbuminuria (29.1%). These findings are in agreement with Kanna D et al. (2020)[8], who reported a strong association between retinal microvascular abnormalities and albuminuria, highlighting the shared microvascular pathology affecting both renal and retinal circulation.

Prevalence of Microalbuminuria in Essential Hypertension: The prevalence of microalbuminuria in the present study was 41.5%, which is comparable to previously reported rates ranging from 25% to 50% in hypertensive populations. Ren Q et al. (2020)[9] reported a prevalence of approximately 35%, while El Mokadem M et al. (2020)[4] observed microalbuminuria in nearly 45% of untreated hypertensive patients. Indian studies have also reported similar prevalence rates, reflecting the high burden of undetected microvascular damage in hypertensive patients. The higher prevalence observed in the present study may be attributed to longer disease duration and suboptimal blood pressure control among the study population.

Correlation Between Microalbuminuria and Target Organ Damage: The correlation analysis in the present study demonstrated a strong positive correlation between UACR and left ventricular mass index (r = +0.62) and carotid IMT (r = +0.58), along with a significant negative correlation with eGFR (r = −0.55). These findings are consistent with Tagetti A et al. (2025)[10], who reported similar correlation patterns between albuminuria and cardiovascular as well as renal structural parameters. Additionally, the positive correlation of UACR with systolic blood pressure and duration of hypertension observed in the present study further supports the role of chronic hemodynamic stress in promoting endothelial dysfunction and microvascular injury.

The present study demonstrates a strong and statistically significant association between microalbuminuria and subclinical target organ damage in patients with essential hypertension. A substantial proportion of hypertensive patients exhibited microalbuminuria, which was significantly associated with increased left ventricular mass index, greater carotid intima-media thickness, reduced renal function, and higher prevalence of hypertensive retinopathy. The study also revealed that patients with longer duration of hypertension and higher systolic blood pressure were more likely to develop microalbuminuria and associated organ damage.

Furthermore, the correlation analysis confirmed that urinary albumin excretion positively correlated with markers of cardiac and vascular remodeling and negatively correlated with renal function, highlighting microalbuminuria as a reliable surrogate marker of systemic microvascular injury. These findings emphasize the clinical utility of microalbuminuria as an early, non-invasive, and cost-effective screening tool for identifying high-risk hypertensive patients. Routine assessment of microalbuminuria in essential hypertension can facilitate early detection of subclinical organ involvement and enable timely initiation of intensive therapeutic strategies, thereby reducing long-term cardiovascular and renal complications.

LIMITATIONS OF STUDY

1. The cross-sectional study design limited the ability to establish a causal relationship between microalbuminuria and target organ damage.
2. The study was conducted at a single tertiary care center, which may limit the generalizability of the findings to the broader population.
3. Single-time measurement of urinary albumin-to-creatinine ratio may not reflect long-term albumin excretion patterns.
4. The impact of antihypertensive medications on microalbuminuria and target organ damage was not separately analyzed.
5. Advanced imaging modalities such as cardiac MRI for precise assessment of left ventricular mass were not utilized due to resource constraints.
6. Lifestyle factors such as dietary salt intake, physical activity, and socioeconomic status were not comprehensively evaluated.

1. Kamal G, Avinash S. Prevalence of microalbuminuria and its association with end-organ damage in patients with essential hypertension at a private tertiary care center. Asian Journal of Medical Sciences. 2025 Sep 30;16(10):34-40.
2. AR P. Microalbuminuria in Non-Diabetic Patients with Essential hypertension and its Correlation with Left Ventricular Mass Index: A Cross-Sectional Study. European Journal of Cardiovascular Medicine. 2025 Aug 1;15(8).
3. Lamsal L, Joshi R, Bhattarai M, Parajuli B, Timilsina S, Kunwor B, Chhetri S, Bhandari S, Chaurel A, Bhattarai HB. Prevalence and clinical correlates of microalbuminuria among patients of essential hypertension in tertiary care center of Nepal: A cross-sectional study. Medicine. 2025 Jun 27;104(26):e43075.
4. El Mokadem M, Boshra H, Abd el Hady Y, Kasla A, Gouda A. Correlation between blood pressure variability and subclinical target organ damage in patients with essential hypertension. Journal of Human Hypertension. 2020 Sep;34(9):641-7.
5. Bhowmick D, Chakraborty S, Ali MH, Ghosh K, Acharyya A, Karmakar PS, Banerjee S. Microalbuminuria in hypertension and its relationship to target organ damage: A cross-sectional observational study in a tertiary hospital in Eastern India. Journal of Clinical and Scientific Research. 2023 Apr 1;12(2):134-9.
6. Chen Z, Jiang X, Wu J, Lin L, Zhou Z, Li M, Wang C. Association between short-term blood pressure variability and target organ damage in non-dialysis patients with chronic kidney disease. BMC nephrology. 2024 Mar 21;25(1):111.
7. Baqui MA, Sultana N, Chowdhury MA, Hasan SM, Furkanuddin KM, Aleem MA. Microalbuminuria in Non-diabetic Hypertensive Individuals: A Cross Sectional Observation in Dhaka Medical College Hospital. Journal of Medical Science & Research. 2022;33:17-22.
8. Kanna D, Reddy PB. A study on microalbuminuria in systemic hypertension as an indicator of target organ damage in adult patients at Chengalpattu District. International Archives of Integrated Medicine. 2020 Mar 1;7(3).
9. Ren Q, Ma C, Wang J, Guo X, Ji L, ATTEND Investigators. Albuminuria and other target organ damage in Chinese patients with hypertension and diabetes: a data analysis based on the ATTEND study. Journal of Diabetes and its Complications. 2020 Jan 1;34(1):107470.
10. Tagetti A, Cattazzo F, Marcon D, Romano S, Giontella A, Bortolotti S, Minuz P, Pecoraro L, Brugnara M, Fava C. Subclinical target organ damage in a sample of children and adolescents with solitary functioning kidney. A pilot study. Journal of Hypertension. 2025 Feb 1;43(2):221-7.