C8000 automatic analyzer

Serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total protein (TP), albumin (Alb), total bilirubin (TBil), direct bilirubin (DBil), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr), uric acid (UA), and glucose (Glu) were measured with a Roche C8000 automatic analyzer (Roche, Basel, Switzerland).

A venous blood sample was obtained from the forearm of each participant after an overnight fast of at least 12 hours. Serum or plasma samples were separated within 30 minutes of collection and were stored at −80 °C. Plasma Hcy was measured using an autobiochemical analyzer (Beckman Coulter AU480) with the enzymatic method. This method mainly uses the S-adenosylhomocysteine (SAH) hydrolase reaction principle, in which SAH is hydrolyzed by hydrolytic enzymes into adenosine and Hcy, adenosine is immediately hydrolyzed into ammonia and hypoxanthine, nicotinamide adenine dinucleotide (NADH) is converted to NAD with ammonia and glutamic dehydrogenase, and the concentration of Hcy in the sample is proportional to the NADH transformation rate. Folate was measured using an automated chemiluminescence immunoassay analyzer (MAGLUMI4000) with the electrochemiluminescence method. Hcy and folate were all tested at the core laboratory of the National Clinical Research Center for Kidney Disease, at the Nanfang Hospital in Guangzhou, China. FBG and the standard 75-g OGTT as well as the lipid profiles and serum creatinine (Scr) at baseline were measured on the Roche C8000 Automatic Analyzer in the laboratory of the Chinese PLA General Hospital.

After an overnight fast of at least 12 h, a venous blood sample was obtained from the forearm of each participant. Plasma samples were separated within 30 min of collection and were stored at −80 °C. Plasma Hcy was measured using an electrochemiluminescence method at Southern Medical University Nanfang Hospital National Clinical Research Center for Kidney Disease in Guangzhou. Serum total cholesterol (TC), LDL-C, HDL-C, triglycerides (TG), fasting blood glucose (FBG), and creatinine (Scr) at baseline were measured on a Roche C8000 Automatic Analyzer in the laboratory of Chinese PLA General Hospital. According to the China Adult Dyslipidemia Prevention Guide (2007 Edition) criteria [11 ], we defined TC ≥5.18 mmol/L as hypercholesterolemia, LDL-C ≥3.37 mmol/L as a high level of LDL-C, HDL-C <1.04 mmol/L as low HDL-C, and TG ≥1.7 mmol/L as hypertriglyceridemia. According to results from previous studies [12 (link)], Hcy ≥ 15 μmol/L is often defined as HHcy. Additionally, in the present study, 15 μmol/L was the cut-off value of the upper quartiles of Hcy, so we defined Hcy ≥ 15 μmol/L as HHcy and divided the participants into two groups (Hcy ≥ 15 μmol/L and Hcy < 15 μmol/L) for further analysis.

The following potential confounders and risk factors were extracted from clinical data: age, sex, body mass index (BMI), blood pressure (BP), plasma glucose, HbA1c and self-reported smoking and alcohol use. Sleep parameters were as follows: AHI, ODI, mean oxygen saturation and lowest oxygen saturation. Comorbidities were identified at baseline (carotid atherosclerosis, hyperlipidaemia, atrial fibrillation, hypertension [HTN], chronic obstructive pulmonary disease [COPD], coronary heart disease [CHD] and diabetes from the hospital administrative database over a six-month period before the diagnostic sleep study. These data were assessed by an interviewer who administered the Unified epidemiological questionnaire and were reviewed by three physicians. Blood was drawn for biochemical analysis after overnight fasting. Plasma glucose, 2 h glucose concentration in the standard 75 g oral glucose tolerance test were measured using a Roche C8000 Automatic Analyzer. The categories of covariates were listed in Supplementary Table s-1.

After 12–15 hours of fasting, a venous blood sample was obtained from each participant. Serum or plasma samples were separated within 30 minutes of collection and were stored at −80°C. The Roche C8000 Automatic Analyzer was used for measurement of fasting blood glucose (FBG), the standard 75 g oral glucose tolerance test (OGTT), lipids profiles (including total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides), and serum creatinine (Scr) concentrations.
Scr (μmol/L) was measured using an enzymatic method, and then eGFR was estimated using the equation derived from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) [29 (link)]: eGFR = 141 × min (Scr/κ, 1)^α × max (Scr/κ, 1)^−1.209 × 0.993^Age × 1.018 (if female), where Scr is serum creatinine (mg/dL), κ is 0.7 for females and 0.9 for males, α is –0.329 for females and –0.411 for males, min indicates the minimum of Scr/k or 1, and max indicates the maximum of Scr/k or 1.