Researchers at the HRB Centre for Primary Care Research based in the Royal College of Surgeons in Ireland have completed systematic reviews of validation studies on two clinical prediction rules and found one (the Probability of Repeated Admission Score) to be useful in certain circumstances while the other (the Triage Risk Stratification Tool) was of limited value when used in isolation.

The first rule evaluated was the Probability of Repeated Admission (PRA) risk score in community dwelling older adults. The PRA score was developed in the United States in 1993 and is a questionnaire comprising of eight questions relating to age; gender; presence of chronic medical conditions; health care use and hospital admission in the previous year, etc.

The review found that the PRA score performs well in predicting hospital admission in people categorised as high risk by the score and so has potential for identifying people at increased risk of hospital admission.

However in people categorised as low risk by the score it performs poorly in identifying subsequent admission indicating it is not a reliable way of excluding hospital admission in those categorised as low risk.

Commenting on the review lead author Dr Emma Wallace, a GP and HRB research fellow at the centre, said, ‘Hospital admissions account for a large proportion of healthcare expenditure and have high personal costs for affected individuals. Identifying older people at high risk of hospital admission could allow targeted interventions to occur in the community setting. From a total nine studies, incorporating 8,843 older people, our research found that the PRA score performs well in identifying those at higher risk of hospital admission in the next year'.

A second systematic review carried out at the centre examined the predictive ability of the Triage Risk Stratification Tool (TRST) in identifying older adults at risk of adverse outcomes (namely a return to the Emergency Department and hospitalisation) within one and four months following discharge from the Emergency Department. The TRST score was developed in the United States in 2003, and is made up of five items (history or evidence of cognitive impairment; difficulty walking, transferring or recent falls; five or more medications; emergency department use in the previous 30 days or hospitalisation in the previous 90 days; and a registered nurses' concern).

This review combined results from six studies and involved 3,233 older adults. The analysis of these results indicated that the TRST is of limited clinical utility in identifying older adults at risk of adverse outcomes following discharge from the emergency department.

Commenting on the review Dr Gráinne Cousins, the lead researcher, said, "The provision of optimal assessment and discharge planning for older patients in Emergency Department settings is challenging given the complex needs of older patients, time pressures, and the need to maintain rapid patient turnover. Risk stratification tools capable of identifying high-risk patients could inform patient care, and reduce overcrowding. A triage tool seeks to rule out disease or adverse events, identifying those patients who do not require further testing. Our research found the TRST rule to be limited in its ability to discriminate between those with or without an adverse outcome following discharge from Emergency Departments and should not be used in isolation as a risk stratification tool."

The Clinical Predictions Rules (CPRs) are being investigated as part of a larger HRB-funded project to compile an international register of CPRs relevant to primary care. This register contains details on 433 CPRs that are relevant to primary care, across 17 different clinical domains. These will be incorporated into a computer-based Clinical Decision Support System (CDSS) for use by clinicians at the point of care.