This is an uncontrolled single-center cross-sectional study. All participants signed a Free and Informed Consent Form (FICF), approved by the Committee of Research Ethics of the State University of Ponta Grossa (UEPG) of number 1.879.373.
From April 2017 to June 2019, 59 patients with RA were selected, defined according to the classification criteria of the American College of Rheumatology [13], who were seen in the routine of the rheumatology outpatient clinic of the Regional University Hospital of Campos Gerais (HURCG), in the municipality of Ponta Grossa – Paraná, Brazil. The participants were referred to the University Laboratory of Clinical Analysis (ULCA) of UEPG, for blood collection and subsequent laboratory tests.
Pregnant women, individuals with neoplasms, other rheumatological autoimmune diseases, as well as those who presented some infectious process at the time of care were excluded from the study.
The 59 study participants were divided into two experimental groups considering the presence or not of treatment with GCS. Thus, the group with GCS was formed by 39 patients, while the group without GCS was formed by 20 patients.
The volunteers underwent clinical evaluation and a complete physical examination, which included a count of swollen and painful joints. Information was obtained through interviews and review of medical records. The history of dan each patient in disease-related aspects, such as clinical manifestations (including joint, extra-articular, comorbidities and risk factors for CAD), previous laboratory data and prescribed treatments (current and previous), and diagnostic criteria used, were evaluated.
Interviews and analysis of medical records were evaluated: age, gender, smoking, medications of current and previous use, presence of other autoimmune diseases, as well as history of chronic diseases, such as diabetes mellitus (DM), systemic arterial hypertension (SAH) and cardiovascular disease.
Systemic blood pressure of patients in a sitting position after at least five minutes of rest was determined. Two to three measurements were made for each individual and the purposes of analysis, the mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) blood pressures were used. The patients were weighed and measured on a mechanical scale with anthropometric ruler, without shoes, to calculate body mass index. The waist and hip dimensions were also measured to calculate the waist/hip ratio.
The activity of RA was evaluated by calculating the Disease Activity Score index in 28 joints (DAS28). For this calculation, the following variables were used: count of 28 joints (right and left side: shoulders, elbows, wrists, metacarpanheralangeal, proximal interphalangeal of hands and knees) regarding the presence of pain and edema, us-CRP and visual scale of general health analog / overall activity of the disease evaluated by the patient, whose values range from zero to one hundred. Patients were classified according to Table 1 after DAS28 calculation as follow:
DAS 28-PCR= 0,56*√(ARTDOL) + 0,28*√(ARTEDEM) + 0,36*log (PCR + 1) + 0,014*EVA + 0,96
ARTDOL: painful joint count in 28 joints,
ARTEDEM: count of swollen joints in 28 joints,
VAS: score on the visual analog scale reported by the patient on his overall health assessment, on a scale of 0–100.
Table 1 Classification of the patient regarding the intensity/activity of THE according to DAS28
DAS28
|
Classification
|
< 2.6
|
Remission (inactive disease)
|
≤2.6 a ≤ 3.2
|
Light activity
|
3.2 ≤ ≤ 5.1
|
Moderate activity
|
> 5.1
|
High activity
|
Source: Modified from Van Der Heijde et al [14]
Blood collection was performed by means of venous puncture with a 12-hour fasting patient. Approximately 10mL of blood were collected from each patient, and the samples were transferred to different tubes for the analysis: tube 1 - containing anticoagulant EDTA K+ used to perform glycated hemoglobin fraction A1c (HBA1c), tube2 - containing sodium fluoride anticoagulant, used for centrifugation and separation of separate plasma, for serum glucose dosage according to the standard procedure of ULCA working routine and tube 3 - containing separator gel, being subsequently centrifuged (10 minutes/300 rpm) and the serum separated for different tests.
The us-CRP dosage was performed by the ultrasensitive immunoturbidimetric method- Wiener® and the Rheumatic Factor (RF) dosage was performed by semi-quantitative technique by the Wiener®. The dosages of total cholesterol, HDL cholesterol, LDL cholesterol, glucose was performed by the enzymatic method in the CT300i Wiener®. The measurements of insulin, troponin, Creatine Kinase Myocardial Band- mass (CKMB-mass) and homocysteine were performed by electrochemiluminescence in the COBAS e411® 5 generation. Hba1C was dosed using methodology of High-Performance Liquid Chromatography (HPLC) methodology in the D-10® Biorad.
Part of the serum sample of each patient was separated into aliquots of 300 µl in microtubes, and then they were taken to the freezer at a temperature of -80oC, for subsequent measurement of myeloperoxidase, interleukin-1 β (IL-1 β), interleukin -6 (IL-6) and tumor necrosis factor-α (TNF-α).
IL-1β and IL-6 dosages were performed through enzyme immunoassay (ELISA) methodology, using immuno tools reactive®, following manufacturer's guidelines. For TNF-α was used reactive Sigma-Aldrich brand® the ELISA methodology, following the manufacturer's guidelines. For the evaluation of myeloperoxidase levels, reactive Immunology Consultants Laboratory, Inc®, through ELISA methodology, following the manufacturer's guidelines. The absorbances of these tests were read in synergy H1 microplate reader with control and software for reading Biotek's Gen5® data (BioTek Instruments, Inc., Winooski, Vermont, USA).
The calculation for cardiac risk assessment was applied to the patients' data, according to the 2013 American College of Cardiology (ACC)/ American Heart Association (AHA), Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults [14] using the Heart Risk Calculator, taking into account: gender, age, smoking, ethnicity, diabetes, total cholesterol and HDL cholesterol values in mg/dL, SBP and DBP (mm Hg) and use of antihypertensive therapy.
For the evaluation of IR, the calculation of the HOMA-IR index was used the following formula:
HOMA-IR = [glucose (nmol/L) x insulin (μg/mL) /22.5]
The results were analyzed with student t tests for unpaired samples and Mann-Whitney nonparametric test. The non-parametric model was used only for the variables that even after transformation (logarithmic) did not present normal distribution (Kolmogorov Smirnov test, p<0.05). The significance level adopted was 5% (α=0.05). All calculations were performed with the statistical package SPSS® (Statistical Package for the Social Science) version21.0 (SPSS Inc Chigaco Illinois USA).
It was constructed of a predictive model for cardiovascular risk through a logistic regression that included the following predictor variables: dose of GCS, time of use of GCS, serum myeloperoxidase and serum us-CRP. After normality analysis performed with the Kolmogorov-Smirnov test, the variables did not present normal distribution (p<0.0001), so they were dichotomized according to the reference values. Glucocorticoid dose: ≤7.5mg/day of prednisone (safe) and >7.5mg/day (cardiovascular risk), Glucocorticoids use time: ≤3 months (safe) and >3 months (cardiovascular risk), Myeloperoxidase: ≤350ng/mL (normal) and >350ng/mL (high) and CRP: ≤0.3mg/dL (low/medium risk) and >0.3mg/dL (high risk). The dependent variable CVR was also dichotomized: low risk (<7.5) and high risk (>7.5). The values of the odds ratio (Odds Ratio (OR)) with a 95% confidence interval are presented. For the statistical model, the relationships were considered significant when p<0.05.
The equation of logistic regression(a) was:
(a) Logit (pi) = b0 + b1.x1,i + … + bk.xk,i
The probability for the dependent binary variable, considering the predictor variables was (equation(b)):
Where:
Logit (PI) is the linear logistic function,
b0 is the constant,
bis the angular coefficient,
x1 is the predictor variable,
p is the probability,
exp is the basis of the Neperian logarithm.
All calculations were performed with the IBM-SPSS version 21 program (IBM Corp. âReleased 2012. IBM SPSS Statistics for Mac OS®. Armonk, NY: IBM Corp.).