A clinical prediction rule or clinical probability assessment specifies how to use medical signs,

symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...

, and other findings to estimate the probability of a specific disease or clinical outcome. Physicians have difficulty in estimated risks of diseases; frequently erring towards overestimation, perhaps due to cognitive biases such as

base rate fallacy The base rate fallacy, also called base rate neglect or base rate bias, is a type of fallacy in which people tend to ignore the base rate (i.e., general prevalence) in favor of the individuating information (i.e., information pertaining only to a ...

in which the risk of an adverse outcome is exaggerated.

Methods

In a prediction rule study, investigators identify a consecutive group of patients who are suspected of having a specific disease or outcome. The investigators then obtain a standard set of clinical observations on each patient and a test or clinical follow-up to define the true state of the patient. They then use statistical methods to identify the best clinical predictors of the patient's true state. The probability of disease will depend on the patient's key clinical predictors. Published methodological standards specify good practices for developing a clinical prediction rule. A survey of methods concluded "the majority of prediction studies in high impact journals do not follow current methodological recommendations, limiting their reliability and applicability", confirming earlier findings from the diabetic literature

Effect on health outcomes

Few prediction rules have had the consequences of their usage by physicians quantified. When studied, the impact of providing the information alone (for example, providing the calculated probability of disease) has been negative. However, when the prediction rule is implemented as part of a critical pathway, so that a hospital or clinic has procedures and policies established for how to manage patients identified as high or low risk of disease, the prediction rule has more impact on clinical outcomes. The more intensively the prediction rule is implemented the more benefit will occur.

Examples of prediction rules

Apache II APACHE II ("Acute Physiology and Chronic Health Evaluation II") is a severity-of-disease classification system, one of several ICU scoring systems. It is applied within 24 hours of admission of a patient to an intensive care unit (ICU): an int ...

* CHADS2 for risk of stroke with atrial fibrillation * CURB-65 * Model for End-Stage Liver Disease * Ranson criteria *

Centor criteria The Centor criteria are a set of criteria which may be used to identify the likelihood of a bacterial infection in adult patients complaining of a sore throat. They were developed as a method to quickly diagnose the presence of Group A streptococca ...

Pneumonia severity index The pneumonia severity index (PSI) or PORT Score is a clinical prediction rule that medical practitioners can use to calculate the probability of morbidity and mortality among patients with community acquired pneumonia. The PSI/PORT score is often ...

* Wells score (disambiguation) *

Orthopaedics Orthopedic surgery or orthopedics ( alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...

** Abbreviated Injury Scale **

Harris Hip Score The Harris Hip Score was developed by William H. Harris to assess the results of hip surgery or hip replacement Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip prosthesis. Hip r ...

** Injury Severity Score **

Kocher criteria The Kocher criteria are a tool useful in the differentiation of septic arthritis from transient synovitis in the child with a painful hip. They are named for Mininder S. Kocher, an orthopaedic surgeon at Boston Children's Hospital and Professor of ...

** Mirel's Score **

NACA score A NACA score (or National Advisory Committee for Aeronautics score) is a scoring system of the severity in cases of medical emergencies such as injuries, diseases or poisonings. It was developed from the National Advisory Committee for Aeronautic ...

Ottawa ankle rules In medicine, the Ottawa ankle rules are a set of guidelines for clinicians to help decide if a patient with foot or ankle pain should be offered X-rays to diagnose a possible bone fracture. Before the introduction of the rules most patients with an ...

Ottawa knee rules The Ottawa knee rules are a set of rules used to help physicians determine whether an x-ray of the knee is needed. They state that an X-ray is required only in patients who have an acute knee injury with one or more of the following: * Age 55 year ...

Pittsburgh knee rules The Pittsburgh knee rules are medical rules created to ascertain whether a knee injury requires the use of X-ray to assess a fracture. Criteria * Blunt trauma or a fall as mechanism of injury AND either of the following: ** Age younger than 12 ...

Revised Trauma Score The Revised Trauma Score (RTS) is a physiologic scoring system based on the initial vital signs of a patient. A lower score indicates a higher severity of injury. Use in triage The Revised Trauma Score is made up of three categories: Glasgow Com ...

References

External links

Clinical Prediction Website

Clinical prediction rules online calculators
{{Central nervous system tests and procedures Health informatics Evidence-based medicine Medical scoring system