Fig. 1

Model A: The four state Multistate Model; 0 is “Admission” without hospital acquired infection (HI); 1 is hospital acquired “Infection”; 2 is the status of the patients who are “Discharged Alive” and 3 is the “Death” of the patient in the hospital. The constant hazard rates, α₀₁ is the hazard rate to acquire the hospital infection during the hospital stay; α₀₂ is the hazard rate to be discharged alive without the HI; α₀₃ is the hazard rate to dead without the HI and α₁₂ is the hazard rate to be discharged alive after the HI; α₁₃ is the hazard rate to be dead after the HI