The Association of Visceral Adiposity Index With Progression of Chronic Kidney Disease
Condition: Obesity, Visceral; Chronic Kidney Diseases; Diabetes Mellitus
MeSH terms: Kidney Diseases; Renal Insufficiency, Chronic; Diabetes Mellitus; Obesity, Abdominal
Study type: Observational [Patient Registry]

Summary: 
      The visceral adiposity index (VAI) has been developed, an indicator for the metabolic
      function of VAT. Previous studies have confirmed the association between the VAI and CKD
      prevalence. In this study, we attempted to investigate the association between estimated
      glomerular filtration rate (eGFR) decline and visceral adiposity.
    

Detailed description: 
      Data were collected from patients with stage 2-5 CKD aged 18 and 80 years and were not on
      dialysis. These patients were followed up in the Nephrology Department of the Usak University
      Research and Training Hospital for at least 1 year between December 2017 and November 2018.
      This study was approved by the Ethics Committee of Usak University School of Medicine. Of 218
      patients with stage 2-5 CKD, only 129 were eligible for the study. The exclusion criteria
      were as follows: missing data, patients older than 80 years, patients taking cholesterol and
      lipid lowering drugs and steroids. Demographic data (age, gender, and medical history such as
      diabetes mellitus and hypertension, medications) were collected from the electronic records
      of the patients, and physical examinations such as blood pressure measurement after 5 minutes
      of rest, height, weight, waist circumference (WC) measured at the level midway from the lower
      rib margin and the iliac crest in the midaxillary line while the patients were standing with
      their feet 25-30 cm apart were performed. Laboratory samples were collected from the
      patients, transported to the laboratory, and stored at -80°C until analysis. HbA1c levels
      were measured using the cation exchange high-performance liquid chromatography system
      (Variant II Turbo HbA1c analyzer, Bio-Rad Laboratories, Hercules, CA, USA). TG, HDL, uric
      acid, calcium, phosphorus, bicarbonate, urine protein, and creatinine levels were analyzed
      with the spectrophotometric method using Architect c8000 automated analyzer and original
      Abbott kits (Abbott Diagnostics Inc, Park City, IL, USA). Two milliliters of blood was added
      to ethylenediaminetetraacetic acid (EDTA) (1 mg/ml blood) and mixed thoroughly to perform
      complete blood count by Mindray BC 6800 (Mindray Bio-Medical Electronics Co., Ltd, Shenzhen,
      China). Parathyroid hormone (PTH) was analyzed with the electrochemiluminescence method using
      the ADVIA Centaur analyzer (Siemens Healthcare Diagnostics, Munich, Germany). Serum
      creatinine levels were measured over a 1-year interval. The eGFR was calculated using the
      Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The stages of CKD were
      defined according to eGFR as stage 2 mild CKD (eGFR = 89-60 mL/min/1.73m2), stage 3a moderate
      CKD (eGFR = 45-59 mL/min/1.73m2), stage 3b moderate CKD (eGFR = 30-44 mL/min/1.73m2), stage 4
      severe CKD (eGFR = 15-29 mL/min/1.73m2), and stage 5 end-stage CKD (eGFR = <15
      mL/min/1.73m2). The eGFR change was calculated as the percentage of change in eGFR in 1 year
      to baseline eGFR. VAI was calculated using the formula
      (WC/36.8+(1.89xBMI))x(TG/0.81)x(1.52/HDL) for women and
      (WC/39.68+(1.88xBMI))x(TG/1.03)x(1.31/HDL) for men. BMI was calculated by dividing weight to
      square of height.

      Data were analyzed with the IBM SPSS 22 statistical program. Descriptive statistics were used
      to define the main characteristics of the patients. Shapiro-Wilk and Kolmogorov-Smirnoff
      statistical tests were used to assess the normality of the data. All parameters except
      parathyroid hormone levels were normally distributed. The correlation between the eGFR
      difference, VAI values, and other parameters was tested with the Pearson correlation test.
      The difference between the patients with different CKD stages according to the eGFR change
      and VAI values were tested by the one-way ANOVA test. The independent samples t-test was used
      to investigate the difference between patients with and without DM and hypertension according
      to VAI values and eGFR change. Partial Correlation is used for to investigate the correlation
      between the two variables, where the effect of other variables is kept constant and
      controlled for both variables. A p value of less than 0.05 was defined as significant.
    

Intervention name(s): eGFR
Intervention type(s): Diagnostic Test
Intervention description(s): estimated glomerular filtration rate
Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Chronic kidney disease patients who were followed up in the Nephrology Department of the
        Usak University Research and Training Hospital for at least 1 year between December 2017
        and November 2018.
      
Keywords: obesity; chronic kidney disease; diabetes mellitus