Proposal to decrease the number of negative temporal artery biopsies

The percentage of negative temporal artery biopsies (TABs) remains very high in patients with suspected giant cell arteritis (GCA). The aim of our study was to identify the clinical predictors of TAB results to improve the effectiveness of this diagnostic procedure.

We performed a cross-sectional study of 125 consecutive patients who underwent TAB in the Department of Internal Medicine of a public tertiary hospital, from January 1997 to March 2002. We compared patients with a positive and a negative biopsy result.

Forty-six of the 125 biopsies (36.8%) were positive for GCA and 79 (63.2%) negative. Temporal artery (TA) thickening (8.01), decreased pulse (5.58), jaw claudication (4.87), and scalp tenderness (4.29) presented the highest positive likelihood ratios (LR+). Erythrocyte sedimentation rate (ESR) (0.11), headache (0.39), TA thickening (0.42), and decreased pulse (0.48) had the lowest negative likelihood ratios (LR-). Only TA abnormalities [odds ratio (OR) 12.3] and scalp tenderness (OR 6) were independent predictors of biopsy results. By excluding patients with no evidence of TA abnormalities, scalp tenderness, or jaw claudication, only 48% of the 125 biopsies would have been performed; 59 negative biopsies would have been prevented, but six positive biopsies would have been missed.

Careful assessment of patients with clinically suspected GCA to rule out artery abnormalities, scalp tenderness, and jaw claudication can lead to a dramatic decrease in the percentage of negative biopsies. This observation may contribute to improving the physician's decision-making process when contemplating TAB.