Table 2.
Illustration of Calculating of Adverse Event Rates
| Numerator and Denominator | Patient ID | Total | |||
|---|---|---|---|---|---|
| A | B | C | D | ||
| No. of adverse events that occurred during a hospitalization (n) | 2 | 1 | 0 | 0 | 3 |
| No. of adverse events for which a patient was at risk during a hospitalization (n) | 8 | 7 | 4 | 9 | 28 |
| No. of patients who experienced 1 or more adverse events | 1 | 1 | 0 | 0 | 2 |
| No. of patients (n) | 1 | 1 | 1 | 1 | 4 |
| Calculating of adverse event rates | |||||
| Rate of occurrence of adverse events (%)a | 3÷28×100=10.7% | ||||
| Rate of patients with 1 or more adverse events (%)b | 2÷4×100=50.0% | ||||
a
The numerator is the number of adverse events that occurred and the denominator is the number of adverse events for which patients were at risk.
b
The numerator is the number of patients who experienced 1 or more adverse events and the denominator is the number of hospitalizations.