1.1 patient selection:
A total of 1,153 elderly patients with AF who were hospitalized in the First Hospital Affiliated to Chongqing Medical University from 2014 to 2021 were retrospectively collected using a cross-sectional study method. Among them, 490 patients were male, and 663 patients were female, aged 78.37±7.21 years. All patients completed blood biochemistry and colour Doppler echocardiography.
1.2 Inclusion criteria:
Patients were ≥65 years old and met the diagnostic criteria for AF: A single-lead electrocardiogram (≥30s) or 12-lead electrocardiogram (≥10s) showed the disappearance of P waves, which were replaced by fibrillation waves (f-waves) with irregular size, morphology, time limits, and absolute irregularity in the RR interval. There were three types of AF included: persistent AF (AF duration ≥ 7 days), long term persistent AF (7 days < AF duration ≤ 1 year), and permanent AF (AF duration > 1 year)[9] .
Definition of HUA: fasting SUA levels >420 umol/L in men and >360 umol/L in women on a normal purine diet[8].
In total, 1153 patients with AF were included, 554 had HUA, and 599 had a normal SUA concentration.
1.3 Diagnostic criteria for comorbidities:
The criteria for diabetes mellitus(DM) were as follows: fasting blood glucose ≥7.0 mmol/L, or 2-hour blood glucose ≥11.1 mmol/L on oral glucose tolerance test, or typical symptoms of three more than one and random blood glucose ≥11.1 mmol/L [10].
Hypertension status was defined as a systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg measured three times not on the same day without the use of antihypertensive medication; or patients with a previous definitive diagnosis of hypertension and being treated with antihypertensive medication [11].
Gout: urate crystals in the joints with gout stones, arthralgia, and arthritis[12].
Coronary artery disease: myocardial infarction manifested by 12-lead electrocardiogram, atherosclerotic stenosis of ≥50% of the lumen of one of the coronary arteries on angiography, or a previous history of coronary stent implantation. Stroke: imaging evidence of stroke on computed tomography (CT) or magnetic resonance imaging (MRI)[13].
1.4 Exclusion criteria
1. Inflammatory stress conditions such as acute infectious diseases, autoimmune diseases, acute gout, acute myocardial infarction, acute stroke, acute heart failure, and other inflammatory conditions, may affect the blood uric acid level.
2. Degenerative cardiac valvular diseases, congenital heart disease, rheumatic heart disease, hypertrophic cardiomyopathy, dilated cardiomyopathy
3. Chronic obstructive pulmonary disease, malignant tumors. These diseases can lead to malignancy, which can affect blood uric acid and cardiac remodeling.
This was a retrospective case observation study, and the ethics committee of the First Affiliated Hospital of Chongqing Medical University pardoned the written informed consent of the patients.
1.5 Clinic data and measurement for index
1.5.1 Data processing:
eGFR:
For Male: serum creatinine (Scr) >80 μmol/L, eGFR=141(Scr μmol/L/88.4/0.9)-1.209*0.993 age(years); Scr≤80 μmol/L, eGFR=141(Scr μmol/L/88.4/0.9)-0.411*0.993 age(years).
For female: Scr>62μmol/L, eGFR=144(Scr μmol/L/88.4/0.7)-1.029*0.993 age(years); Scr≤62mol/L, eGFR=144(Scr μmol/L/88.4/0.7)-0.329*0.993 age(years) [14].
BMI = body mass (Kg)/[height (m)]2[13, 15].
1.5.2 Measurement of clinical biochemical indicators:
Glycosylated hemoglobin (HbA1c) was determined by high-performance liquid chromatography. White blood cell (WBC) count was calculated via Sysmex XN-1000 analysis (Sysemx Corporation, Kobe, Japan)[16], and neutrophils/lymphocytes (NLR) were calculated manually. Creatine kinase isoenzyme (CK-MB), troponin I (cTnI), and myoglobin (MYO) were detected by chemiluminescence, and amino-terminal brain natriuretic peptide (NT-proBNP) was measured by enzyme-linked immunosorbent assay (ELISA).
1.5.3 Measurement of cardiac structure and function:
Right atrial diameter (RAD), right ventricular diameter (RVD), left atrial diameter (LAD), left ventricular end-systolic diameter (LVSD), left ventricular end-diastolic diameter (LVDD), interventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular ejection fraction (LVEF)[17], and left ventricular ejection fraction (LVEF)[18] were measured by transthoracic 2-dimensional M-mode echocardiography using the GE Vivid7 full-digital color Doppler ultrasound. LVEF)[17].
1.6 Statistical analysis:
SPSS 26.0 software was used for statistical analysis. Categorical variables were expressed as percentages (%), and the chi-square test was used for between-group comparisons. Continuous variables were expressed as mean ± standard deviation (x ± SD). Normally distributed data were compared between groups using independent samples t-test, and nonnormally distributed data were compared between groups using rank sum test. Pearson correlation analysis was used for univariate analysis, and dichotomous logistic regression analysis was used for multivariate analysis. p < 0.05 was considered statistically significant.