Impact factors of multiple organ dysfunction syndromes complicating acute myocardial infarction in the elderly: multivariate logistic regression analysis

Introduction

Multiple organ dysfunction syndrome (MODS) is one of the leading causes of inhospital mortality after acute myocardial infarction (AMI) in the elderly. The identification of patients at increased risk of MODS in the immediate postmyocardial infarction period could therefore aid in targeting more aggressive treatment, thereby leading to improved outcomes in these patients.

Methods

Eight hundred patients 60 years of age and older, who presented after onset of symptoms and had either ST elevation in any two contiguous leads or new left bundle branch block, were admitted to the Chinese PLA General Hospital from 1 January 1993 to 30 June 2006. Patients were divided into two groups, based on the patients with or without MODS in the immediate postmyocardial infarction period. Data were obtained from case-record forms. The clinical characteristics, risk factors, clinical presentation, and complications were analyzed. All statistical tests were two-sided and nominal P values with a threshold of 0.05 were used in these exploratory analyses. All baseline variables on univariate analyses with P < 0.05 were included as candidate variables in the multivariable models.

Results

Of the 800 patients enrolled, 27 patients (3.4%) developed MODS within 30 days after AMI. Patients with MODS had higher mortality rates (55.6% vs 11.6%, P < 0.001) and more complications of cardiogenic shock (25.9% vs 6.2%, P < 0.001), heart failure (59.3% vs 18.2%, P < 0.001), arrhythmia (44.4% vs 26.4%, P < 0.05) and pneumonia (55.6% vs 16.3%, P < 0.001) at 30 days, compared with patients without MODS. From multivariate logistic regression analysis using MODS as the dependent variable and the major acute symptoms during AMI, risk history, inhospital complication and so on as the independent variables, the major determinants of the MODS secondary to AMI inhospital were shortness of breath (OR = 2.64, 95% CI = 1.13–6.16), heart rate on the first day of admission (OR = 1.74, 95% CI = 1.14–2.64), inhospital complication of heart failure (OR = 3.03, 95% CI = 1.26–7.26) and pneumonia (OR = 2.82, 95% CI = 1.18–6.77).

Conclusion

These findings demonstrate that the heart rate on the first day of admission and inhospital complication of heart failure and pneumonia were the independent impact factors of MODS complicating AMI in the elderly.