Study Design and participants' characteristics
This research was a cross-sectional, population-based study carried out in the medical wards of a tertiary care hospital in Erode. The participants comprised individuals who sought care at health centers in Erode. The study included individuals of all genders, aged 40–59 years, who were residents of Erode, willing to participate, and diagnosed with non-communicable diseases such as Diabetes Mellitus, Hypertension, Dyslipidemia, and Obesity.
The exclusion criteria encompassed incomplete questionnaires, unwillingness to participate in the tests, and pre-existing renal diseases or other conditions that could potentially impact renal function. Ultimately, a total of 317 eligible middle-aged individuals were included in the study. The study was conducted by the Declaration of Helsinki and was approved by the Institutional Ethics Committee of JKKN College of Pharmacy (JKKNCP/IEC-CER/0522123/38). Before the commencement of the study, all participants provided their written informed consent.
The research took into account a variety of characteristics of the participants, including their age, gender, place of residence, level of physical activity, dietary habits, and medical history. The age of the participants was divided into four categories: 40–44, 45–49, 50–54, and 55–59 years. The International Physical Activity Questionnaire (IPAQ) was used to classify physical activity levels as high, moderate, or low.17 Dietary habits were categorized as healthy, moderate, or unhealthy based on the Healthy Eating Index (HEI) score.18,19 The duration of conditions such as diabetes and hypertension was determined through direct patient interviews. Information on current smoking habits and alcohol consumption was also collected.
Metabolic Syndrome Assessment
Risk factors for renal failure, including hypertension, dyslipidemia, waist circumference, smoking, blood pressure, fasting blood glucose, lipid analysis, BUN/creatinine, and BMI were analyzed. Metabolic syndrome was diagnosed based on the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III).20 Participants were diagnosed with metabolic syndrome if they met three or more of the following five criteria: waist circumference ≥ 90 cm (men) or ≥ 85 cm (women), fasting blood sugar ≥ 100 mg/dL, triglycerides > 150 mg, HDL –C level < 40 mg/dL (men) or < 50 mg/dL (women), and blood pressure ≥ 130/85 mmHg. The data from participants diagnosed with metabolic syndrome were then analyzed.
Biochemical Analysis
Blood samples were primarily drawn from the median cubital and cephalic veins after a minimum of 8 hours of fasting. The samples were refrigerated and sent to a diagnostic medical laboratory for analysis within 24 hours. The levels of triglycerides, HDL-C, and fasting blood glucose were measured using enzymatic methods on Lipid Biosensor (TamilNadu, India).21
Chronic Kidney Disease Assessment
The assessment of chronic kidney disease (CKD) was conducted using the estimated Glomerular Filtration Rate (eGFR), calculated with the Cockcroft-Gault formula.22 This formula takes into account the patient’s creatinine levels, age, gender, and ethnicity: CrCl = 72×serum creatinine in mg/dL (140 − age in years) weight in kg
[For females, the result is multiplied by a factor of 0.85].
Following the National Kidney Foundation- Kidney Disease Outcomes Quality Initiative (NKF-KDOQI), CKD was categorized into five stages: normal (stage 1), mildly decreased (stage 2), mildly to moderately decreased (stage 3a), moderately to severely decreased (stage 3b), and severely decreased (stage 4) (stage 1, eGFR ≥ 90 mL/min/1.73 m2; stage 2, 89 to 60 mL/min/1.73 m2; stage 3a, 59 to 45 mL/min/1.73 m2; stage 3b, 44 to 30 mL/min/1.73 m2; and stage 4, < 30 mL/min/1.73 m2, respectively).23
Our research aimed to understand the effects of metabolic syndrome on the progression of renal function deterioration. To achieve this, we categorized participants into five distinct groups based on their renal function: normal, mildly decreased, mildly to moderately decreased, moderately to severely decreased, and severely decreased. We then proceeded to analyze various factors that could potentially influence the deterioration of renal function.
Statistical Analysis
Data were collated in an Excel spreadsheet and analyzed using SPSS version 27.0.1.0. The mean ± standard deviation (SD) for continuous variables was calculated, and the number of participants was expressed as a percentage for categorical variables. Hypothesis testing for continuous variables was performed using an independent t-test and One-way ANOVA to examine differences in the mean values between groups. For categorical variables, the Chi-squared test and X2-trend test were used to identify differences in proportions. Multiple logistic regression models were developed to investigate the association between the metabolic components of metabolic syndrome and chronic kidney disease (CKD). A p-value of less than 0.05 was considered statistically significant.