Estudo caso controle de fatores associados à cardiopatia chagásicaem pacientes com mais de 50 anos

Abstract

Chagas disease still remains as an important endemic illness in Brazil, and its prevalence is only increasing as the population ages. Yet, very few studies have been conducted specifically on the elderly and the factors associated with Chagas heart disease. This study has therefore attempted to (1) describe the social, demographic, epidemiological and clinical characteristics of Chagas patients seen in an outpatientsetting; (2) assess and correlate the findings of non-invasive cardiovascular diagnostic tests (ECG, Holter monitoring, Doppler echocardiogram, and ergometric testing); and (3) identify the factors in connection with Chagas heart disease. A descriptive, casecontrolmethodology was adopted to look into Chagas patients over 50 years of age seen at the Chagas Disease Ambulatory of the UFMG University Hospital (HCUFMG) between 1997 and 2005. Social, demographic, epidemiological, and clinical (systemic hypertension) explanatory variables were closely examined against patient outcomes. The Control group comprised patients bearing undetermined chronic form of the disease while the Case group contained those with Chagas heart disease (altered ECG). The data set was treated using single-variable and multivariate analysis. The descriptive study included 97 patients with average age of 57,6 years, mostly females (56,7%) and non-whites (64,9%) carrying out on-the-job tasks of moderate (58,8%) to high (26,8%) intensity. Most (67%) claimed to be non-smokers, while 47,4% reported current or previous drinking. Clinical categorization randomly showed that 52,6% of patients belonged to group Ia (free of heart disease), 45,4% of whom with undetermined chronic form of disease, and 47,4% to group II (heart disease present), 26,8% with esophageal involvement and 17,5% with colon disease. Subgroup IIa (altered ECG and normal Doppler echocardiogram) included 65,2% of patients ongroup II, while IIb (EF > 45%) accounted for 23,9% and IIc (EF < 45%) 10,9%. No patients were allotted into group Ib (normal ECG and altered Doppler echocardiogram), confirming the value of a normal ECG to exclude Chagas heart disease. Electrical conduction disorder was the most prevalent ECG finding. Doppler echocardiograms presented alterations for 16,5% of patients, while 48,1% of strain test and 59,5% ofHolter monitoring results were anomalous. Lowns classification for arrhythmia complexity made the correlation between Holter monitoring and ergometric testing evident (Spearman: 0,704; p = 0,000). The agreement between Holter monitoring and Doppler echocardiogram results was significant, however weak (Fisher: p=0,019; Kappa: 0,193; p=0,011). Poor agreement (Kappa: 0,236) was found betweenergometric testing and ECG. Single-variable analysis associated the following variables to heart disease with 5% significance and clinical relevance: age (OR= 1,087; CI 95%: 1,011-1,169), categorized age in two groups of patients with 50-59 years of age and 60 or over (OR=2,89; p=0,03) and family history of heart disease (OR=2,683; CI 95%: 1,087-6,623). Gender was not identified as a risk factor for heart disease (85% statistical power and 5% significance). Multivariate analysis indicated that categorized age and family history of heart disease are factors associated with Chagas heart disease. In conclusion, there was correlation although weak between ECG and ergometric testing, Holter monitoring and Doppler echocardiogram, and Holter monitoring and ergometric testing. Age and family history of heart disease hadsignificance of 5% and proved to be variables associated with Chagas heart disease both on single-variable and multivariate analysis. There was no difference between groups in relation to gender, skin color, and on-the-job physical strain.