1 National Centre for Healthcare Research and Pharmacoepidemiology, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy; Unit of Biostatistics, Epidemiology and Public Health, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy.
2 Cardiovascular Center, University Hospital and Health Services, Trieste, Italy; Cardiology Unit, Papa Giovanni XXIII Hospital Bergamo, Italy. Electronic address: anita.iorio@hotmail.it.
3 National Centre for Healthcare Research and Pharmacoepidemiology, Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy; Biostatistics Unit, Department of Medical Sciences, University of Trieste, Trieste, Italy.
4 Cardiovascular Center, University Hospital and Health Services, Trieste, Italy.
5 Cardiology Unit, Papa Giovanni XXIII Hospital Bergamo, Italy.