Clinical and technical determinants of positive temporal artery biopsy: a retrospective cohort study

Temporal artery biopsy (TAB) is one of the diagnostic tools to confirm the diagnosis of giant cell arteritis (GCA). We aim to evaluate the clinical and technical determinants of a positive biopsy. Demographics, clinical, technical, and laboratory data of all TAB's performed between 2007 and 2019 at a single academic medical center. 107 biopsies performed for 103 patients were included; 72.9% were female, and 27.1% were male. The mean age at the time of biopsy was 67.1 +/- 9.3 years. One biopsy was excluded for lack of arterial tissue content. Of the remaining 106, 19.6% were positive. The length of the biopsy and the number of arterial cross-sections were not significantly associated with its result. A positive biopsy was seen more in patients with low albumin (p = 0.010) and hypothyroidism (p = 0.017) but less in those with prior glucocorticoids treatment (p = 0.028). Predictors of a positive biopsy included male gender [OR 4.029, 95% CI (1.330-12.209), p = 0.014]; elevated ESR [OR 3.998, 95% CI (1.908-6.787), p = 0.023]; polymyalgia rheumatica (PMR) symptoms [OR 5.121, 95% CI (2.094-9.872), p = 0.001]; and advancing in age (6.5% per every additional year), [OR 1.065, 95% CI (1.005-1.130), p = 0.033]. 53.7% of the patients were eventually diagnosed with GCA; 39.2% of them were based on positive biopsy. In conclusion, old age, male gender, elevated ESR, and PMR symptoms increase the odds of positive TAB. Technical factors, such as biopsy length and the number of cross-sections, did not influence eventual biopsy results, highlighting the pivotal role of the clinical presentation of the patients in selecting patients for TAB.