Study Participants
This was a retrospective study with data from the largest comprehensive dermatology treatment centre in Heilongjiang Province, with the majority of patients coming from Heilongjiang Province or the surrounding provinces. The study population was divided into a psoriasis group and a control group, in which the psoriasis group consisted of 1,067 patients with psoriasis who were first admitted to the Department of Dermatology of the First Affiliated Hospital of Harbin Medical University from 1 January 2014 to 31 June 2021, and the control group consisted of 1,110 physical examiners in the same period. All data for this study were obtained from the electronic medical records and database registry of the First Affiliated Hospital of the Harbin Medical University. All procedures were approved by the Ethics Committee of the First Affiliated Hospital of Harbin Medical University, No. IRB-AF /SC-04/01.0, and informed consent was waived due to the retrospective nature of the study.Research involving human research participants have been performed in accordance with the Declaration of Helsinki. we confirming that all experiments were performed in accordance with relevant guidelines and regulations.
Inclusion criteria
We included patients aged ≥ 16 years with psoriasis and controls, diagnosed according to internationally recognised International Classification of Disease (ICD) codes. For data accuracy, we established the following exclusion criteria: (1) incomplete medical records; (2) familial hyperlipidaemia, familial hypertension, type I diabetes mellitus, and severe endocrine system disorders; (3) use of medication affecting lipids within three months; and (4) those with repeated multiple hospitalisations or duplicate medical records.
Definition and collection of data
This study defines dyslipidaemia in the traditional sense7, referring to patients with high total cholesterol (TC)), high triglycerides (TG), and low high-density lipoprotein (HDL). In a broader sense, dyslipidaemia also typically includes abnormalities in low-density lipoprotein (LDL), Apolipoprotein (Apo) A, Apo B, and lipoprotein (Lp) (a). Among all the blood lipid indices, the abnormality of Apo A and HDL was lower than the normal value, and the abnormality of the remaining values was higher than the normal value. The normal value range based on hospital laboratory department’s regulation: TC: 3.35 mmol/L~5.71 mmol/L; TG:0.48 mmol/L~2.25 mmol/L; HDL1.03 mmol/L~1.55 mmol/L; LDL0.26 mmol/L ~ 4.11 mmol/L; Apo A 1.2 g/L~1.6 g/L; Apo B 0.8 g/L~1.05 g/L; L p(a) 0.01~400 mg/L.
A history of smoking was defined as an average of >20 cigarettes per day for smokers, and a history of alcoholism was defined as an average of >200 g of alcohol per day for drinkers. As defined by the FRS score, CVD history in this study was defined as having any of the following: coronary atherosclerosis, myocardial infarction (MI), coronary artery supply deficiency, angina pectoris, ischemic stroke, haemorrhagic stroke, transient ischemic attack, peripheral arterial disease, and heart failure.
The data collected included the following: (1) General characteristics: sex, age, and body mass index (BMI). (2) Psoriasis-related data: psoriasis area and severity index (PASI) and course of psoriasis. (3) CVD-related risk factors: history of CVD, smoking, alcoholism, hypertension, systolic blood pressure, diabetes, and lipid indicators. The lipid indicators collected included TC, TG, HDL, Apo A, Apo B, LDL, and Lp (a).
Study design
To investigate CVD risk factors, a retrospective study was conducted on the following groups:(1) 1,067 patients with psoriasis (psoriasis group) and 1,110 physical examiners without psoriasis (control group). (2) In the psoriasis group, according to the course of disease ≤10 years (n=682) and >10 years (n=385); and (3) according to the severity of PASI≤10 (n = 372) and PASI > 10 (n = 695).
To compare CVD risk predictors, patients with psoriasis who had no history of CVD and were older than 30 years were extracted from the psoriasis group and referred to as the "psoriasis prediction group” (n = 705). These patients were compared with 768 matched controls, where the FRS score was used to calculate the CVD risk score for the next 10 years and the predicted cardiac age of the participants6.
FRS score
The "General CVD Risk Prediction" model (see Appendix 1) is derived from the Framingham Cardiovascular Institute6 and is based on eight factors: sex, age, total cholesterol, HDL, systolic blood pressure level, treatment of hypertension (yes/no), smoking status, and history of diabetes. To perform CVD risk assessment and stratification, patients were classified by the FRS score into five risk categories: very low risk group (< 1 point), low risk (1–6 points), medium risk (6–20 points), high risk (20–30 points), and very high risk (>30 points).Patients are divided into four categories according to World Health Organization's age regulations: youth group (18–44 years), middle aged group (45–59 years),the young old group (60–74 years), and old people (>75 points years).
Statistics
All statistical analysis was performed using SPSS 25.0 software. Categorical variables were compared using the chi-square test, continuous variables that conformed to a normal distribution were compared using t-tests, continuous variables that did not conform to a normal distribution were compared using Mann–Whitney U-tests, and multi-factor logistic regression was used to calculate the odds ratio (OR), p < 0.05 was considered to be statistically significant.