Objective: To perform a decision analysis of temporal arteritis (TA) to guide clinicians in the interpretation of diagnostic testing and choice of therapy.
Design: Computer-based decision analytic model.
Methods: A 785-node decision tree was created that reflects common testing and therapeutic options for a patient with suspected TA. A comprehensive literature search was then performed. From this search, point estimates and distributions for pooled probabilities and utilities were derived using inverse variance weighting and random effects techniques. Employing utility analysis, this decision model selects the diagnostic/therapeutic pathway resulting in the greatest utility for any user-defined set of patient characteristics on presentation.
Main outcome measure: Using utility analysis, the diagnostic/therapeutic pathway that results in the least expected disutility is selected as the optimal course of action.
Results: The choice of diagnostic testing depends on several factors, including patient age, symptoms, and clinical findings. These factors can be used to calculate the pretest probability of TA being present. The optimal selection of diagnostic tests (laboratory or biopsy) depends on the pretest probability of disease. A temporal artery biopsy is recommended under most circumstances, with the choice of a unilateral versus bilateral biopsy depending upon blood test results and calculated pretest probability. A few scenarios exist in which blood tests alone can rule in or rule out TA without the need for biopsy. Empiric steroid therapy is almost never recommended.
Conclusions: In TA, both the disease and its treatment are hazardous for the patient. Clinicians should have a very low threshold to initiate a diagnostic workup for TA. Physicians are often uncertain when a temporal artery biopsy is indicated and whether to perform a unilateral or bilateral biopsy. Often, the pathway chosen is not evidence based. Although the biopsy has long been considered the gold standard for diagnosis, it is invasive and less than 100% sensitive. The decision whether to undertake unilateral or bilateral biopsies is difficult, and our decision model delineates a method for choosing.