Clinical predictors of patient related delay in the VIENNA ST-elevation myocardial infarction network and impact on long-term mortality

Background: While contributors to system delay in ST-elevation myocardial infarction (STEMI) are well described, predictors of patient-related delays are less clear. The aim of this study was to identify predictors that cause delayed diagnosis of STEMI in a metropolitan system of care (VIENNA STEMI network) and to investigate a possible association with long-term mortality. Methods: The study population investigated consisted of 2366 patients treated for acute STEMI in the Vienna STEMI registry from 2003-2009. Multivariable regression modelling was performed for (a) onset of pain to first medical contact (FMC) as a categorical variable (pain-to-FMC <= 60 min versus >60 min: 'early presenters' versus 'late presenters'); and for (b) onset of pain-to-FMC (min) as a continuous variable. Results: After multivariable adjustment, female sex (odds ratio (OR) 1.348; 95% confidence interval (CI) 1.013-1.792; p=0.04) and diabetes mellitus (OR 1.355; 95% CI 1.001-1.835; p=0.05) were independently associated with late presentation in STEMI patients, whereas cardiogenic shock (OR 0.582; 95% CI 0.368-0.921; p=0.021) was a predictor of early diagnosis. When onset of pain-to-FMC was treated as a continuous variable, female sex (p=0.003), anterior infarction (p=0.004) and diabetes mellitus (p=0.035) were independently associated with longer delay, while hyperlipidaemia (p=0.002) and cardiogenic shock (p=0.017) were strong predictors of short pain-to-FMC times. Three-year-all cause mortality was 9.6% and 11.3% (p=0.289) for early and late presenters, respectively. After adjustment for clinical factors (sex, age, diabetes, current smoking, hypertension, hyperlipidaemia, cardiogenic shock and location of myocardial infarction) only a trend for increased risk of all-cause death was observed for longer pain-to-FMC times in a cox regression model (hazard ratio (HR) 1.012; 95% CI 0.999-1.025 for every 10 min of delay; p=0.061). Interestingly, early presentation within one hour of symptom onset was not associated with three-year mortality survival (HR 1.031; 95% CI 0.676-1.573; p=0.886). Conclusion: In this all-comers study of STEMI patients in the VIENNA STEMI network, cardiogenic shock was the strongest predictor of short patient-related delays, whereas a history of diabetes and female sex were independent associated with late diagnosis in STEMI. After adjustment for clinical confounders, patient related delay did not significantly impact on long-term all-cause mortality.