Cardiovascular diseases (CVDs) remain the leading cause of mortality and morbidity globally, with over 80% of deaths occurring in low- and middle-income countries (1). Despite the fact that a significant portion of these deaths are preventable, they continue to rise, primarily due to inadequate preventive measures. Projections suggest that by 2030, approximately 23.6 million people will die from CVDs (1). This increase is largely attributed to the worsening cardiovascular risk profiles in developing countries, which are undergoing an epidemiologic transition (1).

Metabolic syndrome (MS) is a cluster of metabolic risk factors for cardiovascular diseases, including atherogenic dyslipidemia, hypertension, obesity, dysglycemia, insulin resistance, and/or hyperinsulinemia (2). The diagnostic criteria for MS have been published by several working groups, each making modifications and revisions in an effort to find a consensus (3). These include the World Health Organization (WHO) criteria, the European Group for the Study of Insulin Resistance (EGIR) criteria, the American College of Endocrinology (ACE) criteria, the International Diabetes Federation (IDF) criteria, and the Third Report of the National Cholesterol Education Program Adult Treatment Panel (NCEP ATP III) criteria (3,4,5,6).

The most widely used clinical diagnostic criteria are those of the IDF and NCEP ATP III. According to the NCEP ATP III criteria, an individual is considered to have MS if at least three of the following clinical criteria are met:

• Blood pressure (BP) ≥ 130/85 mmHg,
• Waist circumference (WC) > 102 cm in men and > 88 cm in women,
• HDL cholesterol < 1.0 mmol/L (40 mg/dl) in men and < 1.3 mmol/L (50 mg/dl) in women,
• Triglycerides (TG) ≥ 1.7 mmol/L (150 mg/dl), and
• Fasting blood glucose (FBG) ≥ 5.6 mmol/L (101 mg/dl) (6).

MS has raised considerable concern due to its clear association with an increased risk for coronary artery disease and other cardiovascular events (7). The aim of this study was to assess the prevalence of metabolic syndrome in a population of hypertensive patients attending a tertiary hospital in Odisha.

This cross-sectional study was conducted at VIMSAR Medical College and Hospital in Burla, Odisha. The study protocol was reviewed and approved by the Research and Ethics Committee of the hospital prior to the initiation of the study. The study population consisted of 320 hypertensive subjects (156 males and 164 females), aged 18 years and older, who were attending the hypertensive clinic at the hospital. Participants were selected consecutively from both the male and female hypertensive clinics and were screened for the presence of metabolic syndrome between August and October 2021.

A structured pre-tested interviewer-administered questionnaire was used for data collection. The questionnaire included questions on personal information, history of type II diabetes mellitus, and the measurement of body mass index (BMI), waist circumference, fasting plasma glucose, and fasting lipid profile (including triglycerides (TG), total cholesterol, and high-density lipoprotein cholesterol (HDL-C)).

The diagnosis of metabolic syndrome was based on the NCEP ATP III criteria (6). A patient was classified as obese if the BMI was ≥ 30 kg/m², and abdominal obesity was diagnosed when waist circumference exceeded 102 cm (40 inches) in males and 88 cm (35 inches) in females (8). Dyslipidemia was defined according to the National Cholesterol Education Program - Adult Treatment Panel III (NCEP ATP III) guidelines (6), where hypercholesterolemia was defined as total cholesterol (TC) ≥ 200 mg/dl (5.2 mmol/L), hypertriglyceridemia was defined as triglycerides (TG) ≥ 150 mg/dl (3.38 mmol/L), and low HDL-C was defined as ≤ 40 mg/dl (1.0 mmol/L) in men or ≤ 50 mg/dl (1.2 mmol/L) in women (6). Diabetes mellitus (DM) and impaired fasting glucose were diagnosed based on the American Diabetes Association (ADA) guidelines (9). All laboratory tests were performed at the Chemical Pathology Laboratory of the hospital using an auto-analyzer machine (10).

Statistical analysis was performed using R software. Continuous variables were presented as mean ± standard deviation. Qualitative variables were expressed as proportions and percentages. The Chi-squared or Fisher’s Exact tests were used to compare proportions, while the student’s t-test was used to compare means. A P-value < 0.05 was considered statistically significant.

Among the 320 hypertensive patients, 129 (40.3%) were diagnosed with metabolic syndrome (MS) based on the ATP III criteria. This included 93 males (72.1%) and 36 females (27.9%). The mean age of the patients was 57 ± 12.3 years, ranging from 23 to 88 years. The clinical characteristics of the hypertensive patients in the study are presented in Table 1. The mean systolic blood pressure (SBP) was significantly higher in males (158 ± 14.7 mmHg) compared to females (148 ± 13.9 mmHg) (P < 0.001). However, there was no significant difference in diastolic blood pressure (DBP) between males (91 ± 14.5 mmHg) and females (89 ± 15.9 mmHg) (P = 0.124). The fasting blood glucose (FBG) levels were comparable between the two sexes (P = 0.467). Similarly, high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) levels did not show any statistically significant differences between males and females. Notably, waist circumference (WC) was significantly higher in females (96.9 ± 13.4 cm) than in males (93.1 ± 11.2 cm) (P < 0.001).

Table 1: Clinical characteristics of the hypertensive patients

SBP: Systolic Blood Pressure, DBP: Diastolic Blood Pressure, FBG: Fasting Blood Glucose, HDL-C: High-Density Lipoprotein Cholesterol, TG: Triglycerides, WC: Waist Circumference

The prevalence of individual metabolic syndrome (MS) criteria among the study population is shown in Table 2. Low HDL-C was observed in 34.4% of the participants, with a slightly higher prevalence in males (55.5%) compared to females (44.5%), though this difference was not statistically significant (P = 0.136). Elevated triglycerides (TG) were present in 23.4% of the population, without a significant gender-based difference (P = 0.249). Increased waist circumference was significantly more prevalent among females (62.5%) than males (37.5%) (P < 0.001). Type II diabetes mellitus (DM) was present in 36.6% of the study population, affecting males (53.8%) slightly more than females (46.2%), though this difference was not statistically significant (P = 0.379). However, impaired fasting blood glucose (FBG) was significantly more common in females (65.4%) than in males (34.6%) (P < 0.001).

Table 2: Prevalence of each of the criteria for diagnosis of metabolic syndrome among study population

HDL – C; high density lipoprotein cholesterol, TG; triglycerides, WC; waist circumference, DM; diabetes mellitus, FBG; fasting blood glucose.

The age-wise distribution of metabolic syndrome (MS) prevalence is summarized in Table 3. The overall prevalence of MS in the study population was 38.8%. The prevalence was lowest in individuals aged <30 years (17.6%), increasing to 39.0% in the 31–44 age group, and peaking at 45.7% in the 45–60 age group. In the >60 years group, MS prevalence was 37.6%. The majority of individuals without MS were in the <30 years age group (82.4%), while the proportion of MS cases increased progressively with age.

Table 3: Prevalence of metabolic syndrome among participants based on age group

MS; metabolic syndrome

Hypertension often coexists with other cardiovascular risk factors, increasing the likelihood of metabolic syndrome (MS). In this study, 40.3% of hypertensive patients met the ATP III criteria for MS, a prevalence comparable to findings from Nigeria and other regions globally (1-7). However, significantly higher prevalence rates have been reported in Spain (52%), the United States (62.9%), and Jordan (52%) (8, 9, 10). These variations could be attributed to differences in genetic predisposition, ethnicity, socio-demographic characteristics, lifestyle factors, duration of hypertension, and adherence to treatment protocols (11-13).

Ethnic variations also play a role in MS prevalence. Studies indicate that Black Africans tend to have lower adipose tissue mass for the same body mass index (BMI) compared to Caucasians (14). Findings from the Third National Health and Nutrition Examination Survey (NHANES III) demonstrated a higher prevalence of MS in Caucasian and Hispanic men compared to their Black counterparts (9). Conversely, a study in Abuja, Nigeria reported a much lower MS prevalence (16.8%), which may be due to differences in diagnostic criteria (15).

The study also observed a higher MS prevalence among females, aligning with findings from various global studies (2, 3, 10, 16). This could be attributed to the higher prevalence of obesity among women and socio-cultural factors that limit their engagement in physical activity. However, some studies have reported similar prevalence rates in both genders or even a higher prevalence among men, which could be explained by differences in study methodologies (17-23).

Among the components of MS, central obesity was the most common, consistent with previous studies (2, 16, 21-25). Research from Cameroon also highlighted that central obesity was more strongly linked to MS than insulin resistance, suggesting it may be a key determinant of MS in sub-Saharan Africa (21,26).

MS prevalence tends to rise with increasing age, a trend widely documented (9, 22, 23). In this study, MS was more common in individuals aged ≥ 40 years, likely due to age-related insulin resistance and fat redistribution from peripheral to central areas (24-28). Additionally, hormonal changes associated with aging can contribute to MS pathogenesis. Interestingly, some studies suggest a decline in MS prevalence among the oldest age groups, possibly due to age-related body fat loss (24).

Metabolic syndrome is highly prevalent among hypertensive individuals, emphasizing the need for early detection and intervention. The clustering of multiple cardiovascular risk factors in hypertensive patients heightens their susceptibility to MS. Therefore, routine screening and timely lifestyle modifications—including dietary changes, increased physical activity, and appropriate medical interventions—are essential to reduce cardiovascular disease risk and improve long-term health outcomes.

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