[Risk factors as prognostic factors of hospital mortality in patients with acute myocardial infarction]

Abstract

Objective: To determine whether there are any differences in the prevalence of risk factors between survivors and nonsurvivors among acute myocardial infarction (AMI) patients hospitalized in a county hospital.

Methods: Case histories of AMI patients treated at Department of Medicine, Bjelovar General Hospital from July 1, 1996 until December 31, 2000 were retrospectively analyzed. AMI was diagnosed using the World Health Organization definition. Demographic factors (age and sex), smoking habits, clinical and laboratory results (hypertension, diabetes, blood lipids--total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides), personal history of angina pectoris, myocardial infarction and stroke and family history of atherothrombotic disease were considered as potential risk factors. Comparisons were made between survivors and nonsurvivors during hospital treatment. On group comparisons Student's t-test and chi2-test were used. Statistical significance was set at p<0.05.

Discussion: In a total of 396 study patients, there were 316 (79.8%) survivors, showing male predominance (87.1% vs 67.3% of women; p<0.011). The patients aged under 65 were mainly male (79.6%), and among those older than 65 both sexes were equally represented (male 50.7% vs female 49.3%). Hypertension was more common in women (55.1% vs 42.6%; p=0.016), and smoking in men (31.7% vs 5.4%; p<0.001). The group survivors showed a higher prevalence of hypertension (50.3% vs 35.0% in nonsurvivors; p=0.014) and smoking (25.9% vs 6.3%; p<0.001). The prevalence of diabetes, previous myocardial infarction, angina pectoris, previous stroke and family history of atherothrombotic disease showed no statistically significant differences between survivors and nonsurvivors. Furthermore, a greater number of patients with increased levels of total cholesterol (> or =5.0 mmol/L) and LDL-cholesterol (> or =3.0 mmol/L) were found in the group of survivors than among nonsurvivors. The latter were 8 years older than survivors (71.0+/-9.3 vs 63.0+/-11.9 years; p<0.001). Analysis according to age groups also showed a rise of hospital mortality with age group in both sexes (men: 4.6% in <55 age group vs 22.6% in > or =75 age group; women: 7.1% in <55 age group vs 43.7% in > or =75 age group). A higher percentage of men nonsurvivors were smokers in comparison to female nonsurvivors that also had a lower level of total cholesterol. The prevalence of hypertension showed no significant sex difference.

Conclusion: The prevalence of risk factors, especially the most important ones, i. e. hypertension, smoking and abnormal lipid values in AMI patients should be considered according to sex and age. The impact of these factors on patient outcome, i. e. survival rate during hospital treatment, can only be analyzed taking into account sex and age.