Four cohort studies were included. The total number of participants was 3,667. One study was retrospective; it was unclear whether the other three studies were prospective or retrospective regarding data collection.
In one study there were no cancellations for reasons that could have been foreseen at POA among 59 patients assessed by a nurse specialist or among the control group of 52 patients seen by a doctor.
In the largest study, 8 (0.4%) of 2,762 patients were cancelled on admission for reasons that could have been resolved at the POA. The comparative rate of cancellation for the Health Trust was 10.9%. However, it was uncertain that nurse-led POA was solely responsible for the lower rate of cancellations in the study population, owing to other differences between the ward investigated and the rest of the Trust.
In another study there were 8 cancellations out of 314 patients who had attended the POA clinic over a period of 2 years, compared with 12 out of 162 in the control year before the POA clinic was established. Cancellation due to POA failure could not be ascertained with certainty because the reasons for cancellation were not specified.
The fourth study reported two cancellations (1.1%) for preventable reasons out of 179 patients who underwent POA, compared with 10 (5.9%) of 175 patients in the control group (p<0.05). This corresponded to a 46% absolute reduction in the risk of cancellation (number-needed-to-treat 22).