IJCS | Volume 31, Nº2, March / April 2018

91 Barbosa et al. Impact of risk factors on MRS costs Int J Cardiovasc Sci. 2018;31(2)90-96 Original Article We included patients aged over 30 years, of both sexes, with indication for MRS and CAD confirmed by coronary angiography. Patients who had undergoneMRS combined with other surgeries including valve surgeries, carotid endarterectomy, vascular surgerieswere excluded. Systemic hypertension, diabetes mellitus, dyslipidemia, current or past smoking, sedentary lifestyle, chronic renal failure and obesity were considered risk factors for CAD. Hospitalization costs related to medications, laboratory tests, imaging tests, materials, and healthcare professionals, provided by the cost center, were collected frompatients’ medical records.We used themicro-costing method, in which each intervention performed was individually counted for the total hospitalization costs. The values used as basis of cost estimation were obtained from the Table of Procedures and Medications of SUS Managing System (SIGTAP). Exploratory analysis of the frequencies of categorical variables was performed. Continuous variables were presented as mean, median and other measures of central tendency, dispersion and data ordering, as appropriate. Categorical variables were analyzed by the chi-square test. P-values < 0.05 were considered statistically significant. The SPSS 20.0 (IBM) was used for the analysis. The present studywas approved by the Ethics Committee (approval number 648089), and the study was performed according to the Helsinki declaration. Results A total of 239 patients presenting from 1 to 6 cardiovascular risk factors were evaluated. Seven patients had only one risk factor, 32 patients had two risk factors, 75 patients had three risk factors, 78 four risk factors, 35 had five risk factors and 11 patients had six risk factors. Patients’ characteristics and definitions of cardiovascular risk factors are described in Table 1 and Table 2, respectively. Patients with a higher number of comorbidities showed higher BMI as compared with patients with less risk factors (p < 0.001). Mean age was not significantly different between the groups. The prevalence of cardiovascular risk factors was variable among the subjects, and the most frequent ones were systemic arterial hypertension and dyslipidemia, found in 95.8% and 76.6% of patients, respectively. The prevalence of the risk factors analyzed in the study is shown in Figure 1. Table 3 displays hospitalization costs analyzed by the micro-costing approach, stratified as medications, laboratory tests, imaging tests, materials, professionals and common costs. The occurrence of complications during hospitalization was not significantly different between the groups (Table 4). Deaths were proportional to the number of subjects in each group, with no significant differences between the groups. The numbers of hospital days and ICU days were not different between the groups. Discussion Results of this study represent the costs of MRS alone, encompassing the whole hospitalization period, in a referral hospital for cardiology diseases in the SUS. Anumber of studies have suggested that demographic characteristics of patients, including older age, female sex, left ventricular ejection fraction, number of coronaries involved, previous surgeries and high number of comorbidities, may significantly affect MRS hospital costs. 3 However, an analysis under this perspective has not been performed in Brazil yet. Patients of thepresent study showedahigher prevalence of hypertension, diabetes mellitus, and left coronary artery lesion as compared with patients of similar reports. 4 In all categories, there was a direct relationship between costs and the number of risk factors, with no statistical significance though. Other studies have shown a positive correlation between cardiovascular risk factors and hospital costs. 5,6 Nevertheless, there is evidence suggesting that local factors, such as the country and even the level of hospital complexity may influence the effects of cardiovascular risk factors on hospital costs. 7 In the present study, no significant differences in demographic variables, cause of hospitalization, ventricular function or angiographic data were found between the groups. There were differences in the clinical history and comorbiditiesbetween thegroups; thesedifferences, though, were expected, since the characterization of the groups was based on the presence and the number of comorbidities. In addition, no differences were found with respect to patients’ complications, which account for a considerable percentage of hospitalization costs, not only for the increase in the hospital or ICU stay, but also for the increased use of resources. 8 Nevertheless, other studies have reported a correlation between risk factors and complications during hospitalization, 9 which may lead to higher hospital-related costs.