Study population
The study population was selected from the subjects who have been addressed to the Vibrant America Laboratory for cardiovascular, diabetic, and hepatic panels at the same time. The retrospective analysis was completed using the deidentified clinical data and test results from a total of 438 subjects and hence the study was exempted from the formal ethical review by Western IRB (Washington USA). The mean age (±SD) of the subjects was 48 ± 15 years with a female to the male ratio of 1:1 (50% female, 50% male).
Cardiovascular markers
Blood samples were processed for the separation of serum and further analyzed for a cardiovascular panel comprised of lipids (total cholesterol, LDL, HDL, and triglycerides), apolipoproteins (Apo A1, Apo B), and a lipoprotein marker lipoprotein (a). Total cholesterol was measured by the cholesterol dehydrogenase method via Beckman Coulter AU680 analyzer. Serum levels of LDL, HDL, and triglycerides were measured by an enzymatic-colorimetric method using the Beckman Coulter AU680 analyzer. Other cardiovascular markers such as Apo A1, Apo B, and Lp(a) were also measured by a particle enhanced immunoturbidimetric assay via Roche Cobas 6000 c 501 analyzer.
Table 1. Baseline clinical characteristics of the study population
hs-CRP
low risk: ≤0.9(mg/L)
normal: 1.0~3.0(mg/L)
High risk: ≥3.1(mg/L)
|
n=438
|
Frequency (n)
|
Mean ± SD
|
Male
|
220
|
48.8 ± 14.4
|
Female
|
218
|
48.0 ± 15.5
|
Cardio marker
|
|
|
|
Cholesterol
≤199 mg/dL
|
Low
|
-
|
-
|
Normal
|
389
|
181.4 ± 33.0
|
High
|
49
|
263.9 ± 27.8
|
Low-density lipoprotein
≤99 mg/dL
|
Low
|
-
|
-
|
Normal
|
263
|
99.9 ± 20.6
|
High
|
175
|
158.3 ± 24.4
|
High-density lipoprotein
≥56 mg/dL
|
Low
|
53
|
35.4 ± 5.3
|
Normal
|
385
|
58.4 ± 14.9
|
High
|
-
|
-
|
Triglyceride
≤149 mg/dL
|
Low
|
-
|
-
|
Normal
|
405
|
88.9 ± 35.3
|
High
|
33
|
313.3 ± 107.5
|
Apolipoprotein A1
≥120 mg/dL
|
Low
|
50
|
117 ± 12.9
|
Normal
|
388
|
173.9 ± 31.5
|
High
|
-
|
-
|
Apolipoprotein B
≤89 mg/dL
|
Low
|
-
|
-
|
Normal
|
367
|
89.5 ± 17.6
|
High
|
71
|
137.9 ± 17.4
|
Lipoprotein (a)
≥30 mg/dL
|
Low
|
|
|
Normal
|
273
|
14.0 ± 6.4
|
High
|
165
|
69.8 ± 31.4
|
Diabetic marker
|
|
|
|
Insulin
30-230 ml U/L
|
Low
|
15
|
1.8 ± 0.4
|
Normal
|
387
|
8.6 ± 4.9
|
High
|
36
|
43.2 ± 24.6
|
Ferritin
Male: 30-400 ng/mL
Female: 13-150 ng/mL
|
Low
|
06
|
16.0 ± 3.1
|
Normal
|
372
|
125.2 ± 90.3
|
High
|
60
|
367.6 ± 3
|
Hemoglobin A1c
5.7~6.4(%)
|
Low
|
-
|
-
|
Normal
|
416
|
5.3 ± 2.6
|
High
|
21
|
5.3 ± 2.7
|
Glucose
101~126(mg/dL)
|
Low
|
06
|
60.5 ± 3.0
|
Normal
|
384
|
92.3 ± 9.8
|
High
|
48
|
151.1 ± 71.9
|
Adiponectin
~58.5 (ug/mL)
|
Low
|
24
|
3.2 ± 0.76
|
Normal
|
412
|
16.2 ± 9.5
|
High
|
02
|
-
|
Glycated Serum Protein
~300 (umol/L)
|
Low
|
-
|
-
|
Normal
|
407
|
228.1 ± 34.8
|
High
|
31
|
415.0 ± 140.5
|
Hepatic marker
|
|
|
|
Alkaline phosphatase (ALK)
Male: ~130 (U/L)
Female: ~105 (U/L)
|
Low
|
06
|
35.5 ± 3.2
|
Normal
|
413
|
68.3 ± 16.2
|
High
|
19
|
134.4 ± 36.6
|
Aspartate transaminase (AST)
Male: ~40 (U/L)
Female: ~32 (U/L)
|
Low
|
-
|
-
|
Normal
|
399
|
21.2 ± 5.3
|
High
|
39
|
66.7 ± 62.4
|
Alanine transaminase (ALT)
~42(U/L)
|
Low
|
-
|
-
|
Normal
|
381
|
19.9 ± 7.1
|
High
|
57
|
65.2 ± 37.6
|
Albumin
~5.2(g/dL)
|
Low
|
-
|
-
|
Normal
|
431
|
4.6 ± 0.2
|
High
|
7
|
5.3 ± 0.1
|
Total Bilirubin
~1.3(mg/dL)
|
Low
|
-
|
-
|
Normal
|
424
|
0.5 ± 0.2
|
High
|
14
|
1.6 ± 0.5
|
Total protein
~8.7(g/dL)
|
Low
|
03
|
5.8 ± 0.1
|
Normal
|
419
|
7.1 ± 0.3
|
High
|
16
|
8.3 ± 0.7
|
Diabetic markers
Peripheral blood was obtained from the subjects and immediately processed for serum separation. All samples were subjected to measurement of various diabetic markers such as glucose, insulin, ferritin, hemoglobin A1C, glycated serum albumin, and adiponectin. Separated serum samples were processed for analysis within 2 h, serum samples may be refrigerated at 2-8 ℃ for 8 days if required.
Serum levels of glucose were measured by the enzymatic reference method in which the phosphorylation of glucose to glucose-6-phosphate catalyzed by hexokinase with consumption of ATP. The glucose-6-phosphate is further oxidized into gluconate-6-phosphate by glucose-6-phosphate dehydrogenase in the presence of NADP. The glucose concentration is measured photometrically as the rate of NADPH formation during the reaction. The invitro quantitative determination of serum insulin and ferritin was estimated by electrochemiluminescence immunoassay (ECLIA) analyzed using Elecsys and Cobas E analyzers.
The HbA1c determination is based on the turbidimetric inhibition immunoassay (TINIA) for hemolyzed whole blood. The glycohemoglobin in the samples reacts with an anti-HbA1c antibody to form a soluble antigen-antibody complex. Upon the addition of polyhaptens, the excess anti-HbA1c reacts with the polyhaptens to form an insoluble antibody-polyhapten complex. The complex is further measured turbidimetrically using Roche/Hitachi Cobas c systems.
Serum levels of glycated serum protein are estimated by an enzymatic reaction catalyzed by proteinase K to digest GSP into low molecular weight glycated protein fragments (GPF). The oxidative degradation of GPF is catalyzed by Diazyme’s specific fructosamine to yield peptide fragments of amino acids, glucosone, and H2O2. The amount of H2O2 released is calorimetrically measured at 546-600 nm and is directly proportional to the concentration of glycated serum protein present in the sample.
Serum levels of adiponectin are determined by the latex enhanced immunoturbidometric method. The serum samples were treated with anti-Adiponectin-coated latex and the formation of the antigen-antibody complex is characterized by the increase in the turbidity, which is measured photometrically at 570 nm. The concentration of adiponectin in the samples was determined by constructing a standard curve from the absorbance of the standards.
Hepatic markers
The assay panel includes the estimation of most vital liver enzymes such as Alkaline phosphatase (ALK), Aspartate transaminase (AST), Alanine transaminase (ALT), and other hepatic markers such as albumin, total bilirubin, and total protein. The serum levels of hepatic enzymes by colorimetric analysis using Roche/Hitachi Cobas c auto analyzers.
Serum levels of AST are determined by a two-step enzymatic reaction in which the AST present in the sample catalyzes the transfer of amino group between L-aspartate and 2-oxoglutarate resulting in the formation of oxaloacetate and L-glutamate. Further, the oxaloacetate oxidizes the NADH in the presence of malate dehydrogenase to form NAD. The oxidation rate of NADH is directly proportional to the catalytic activity of AST which is measured as the decrease in the absorbance. The enzyme activity of ALT is determined by the catalytic activity between L-alanine and 2-oxoglutarate. The reduction of pyruvate by NADH in a reaction catalyzed by lactate dehydrogenase results in the formation of L-lactate and NAD. The oxidation rate is directly measured as the catalytic activity of ALT and measured photometrically as the decrease in absorbance. Alkaline phosphatase is measured by the ability of phosphatases to cleave the p-nitrophenyl phosphate onto phosphate and p-nitrophenol in the presence of magnesium and zinc. The enzyme activity is directly proportional to the amount of p-nitrophenol released and measured as the increase in absorbance.
Serum levels of albumin are measured by the development of a blue-green complex between the cationic serum albumin and anionic bromocresol green at an ideal pH of 4.1. The color intensity of the blue-green complex is directly measured as the concentration of albumin. The total bilirubin is determined by a colorimetric diazo method in which the serum bilirubin readily solubilizes and forms a red azo dye complex with 3,5-dichlorophenyl diazonium. The color intensity of the complex is photometrically measured and directly proportional to the amount of total bilirubin. The total protein is estimated by divalent copper which reacts with the protein peptides which forms a characteristic purple-colored biuret complex. The color intensity of the complex is directly proportional to the concentration of protein.
High sensitivity C-Reactive protein
Serum hs-CRP levels were measured using a particle-enhanced immunoturbidimetric method, which measures the agglutinates of hs-CRP with latex particles coated with anti-CRP monoclonal antibodies. The concentration of hs-CRP is measured turbidimetrically on Roche Cobas c 311 analyzers. The functional sensitivity is the lowest hs-CRP concentration that can be reproducibly measured with an inter-assay coefficient of variation of < 10 %.
Statistical Analysis
Clinical data were subjected to retrospective analysis from de-identified subjects using Java for windows version 1.8.161. Non-parametric Mann-Whitney U test was used to compare the serum levels of hs-CRP with normal and altered levels of various serum markers. Pearson’s correlation was carried out to analyze the univariant relationship between serum biomarkers with hs-CRP at p<0.05 significance. All statistical analysis was performed using GraphPad Prism Version 7.00 and a descriptive statistic was used to define the continuous variables (mean ± SD, and median, minimum and maximum).