ESRD hospitalization, transplantation, Medicare costs, and mortality rates are typically represented as “per person-time” to provide more accurate comparisons among groups when follow-up time (i.e., patient exposure time) is not the same in all groups. This can be expressed as per 100, 1000, 100,000, 1 million patient-years or patient-years at risk.
ESRD hospitalization, transplantation, Medicare costs, and mortality rates are typically represented as “per person-time” to provide more accurate comparisons among groups when follow-up time (i.e., patient exposure time) is not the same in all groups. This can be expressed as per 100, 1000, 100,000, 1 million patient-years or patient-years at risk. “Patient-year at risk” means that the denominator of the rate calculation is ascertained by adding exposure times of all patients, where each patient’s exposure time is defined as days spent in a pre-determined time period (i.e., a year), censored only by events such as death or disenrollment, or the end of the time period. Divide the total number of days by 365 to get the actual year value. “Patient-year” means that the denominator of the rate calculation is ascertained by counting all patients who are in the pre-determined time period for at least one day. The expressions “per 100,000 patient-years at risk” and “per million patient-years”