1. Department of MedicinePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
2. Department of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
3. Center for Clinical Epidemiology and BiostatisticsPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
4. Penn Cardiovascular InstitutePerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA