Clinical prediction rules: What are they and what do they tell us?

Abstract

Clinical prediction rules use quantitative methods to build upon the body of literature and expert opinion and can provide quick and inexpensive estimates of probability. Clinical prediction rules can be of great value to assist clinical decision making but should not be used indiscriminately. They are not a replacement for clinical judgment and should complement rather than supplant clinical opinion and intuition. The development of valid clinical prediction rules should be a goal of physiotherapy research. Specific areas in need of attention include deriving and validating clinical prediction rules to screen patients for potentially serious conditions for which current tests lack adequate diagnostic accuracy or have unacceptable cost and risk, and to assist in classification of patients for treatments that are likely to result in substantially different outcomes in heterogeneous groups of patients.

Potential Pitfalls of Clinical Prediction Rules

“…A clinical prediction rule (CPR) is a combination of clinical fi ndings that have statistically demonstrated meaningful predictability in determining a selected condition or prognosis of a patient who has been provided with a specifi c treatment 1,2 . CPRs are created using multivariate statistical methods, are designed to examine the predictive ability of selected groupings of clinical variables 3,4 , and are intended to help clinicians make quick decisions that may normally be subject to underlying biases 5 .…”

“…Th e number of derived or validated CPRs is increasing 6 , specifi cally in rehabilitation medicine where prescriptive studies have been developed for musculoskeletal interventions for low back pain 7,8 , cervical pain 9,10 , and knee dysfunction 11,12 . Clinical prediction rules may best be classifi ed into three distinct groups: 1) diagnostic, 2) prognostic, and 3) prescriptive 1,13 . Studies that focus on predictive factors related to a specifi c diagnosis are known as diagnostic CPRs.…”

“…Clinical prediction rules that are designed to predict an outcome such as success or failure are considered prognostic. Clinical prediction rules designed to target the most eff ective interventions are identifi ed as prescriptive, and these require prospective, longitudinal, randomized controlled trials that compare outcomes aft er selected interventions for subjects who meet a similar score on the CPR 1 .…”

Clinical Prediction Rules in Physical Therapy: Coming of Age?

“…In this context, a CPR can be described as a tool to help physical therapists place a patient within an otherwise heterogeneous diagnostic category (eg, low back pain) into a more homogenous subgroup, based on the patient's likely response to a discrete treatment approach. 1 The need to subgroup, or classify, patients with nonspecific, heterogeneous diagnostic labels into smaller categories based on likely response to a specific treatment has been identified as a central aspect of clinical decision making in physical therapy practice since the foundational work of Sahrmann and others in the 1980's. 4 An appeal of CPRs is their potential to make this subgrouping process more evidence based and less reliant on unfounded theories and tradition.…”

“…In these circumstances, clinical decision making is complex, uncertain, and most likely to benefit from tools such as CPRs. 1,9 Clinical conditions such as patellofemoral pain, low back pain, and neck pain appear to be good targets for CPR development. These conditions are characterized by heterogeneity in clinical presentation and a presumption that relevant subgroups exist within the condition, complicating clinical decision making.…”