Temporal Artery Biopsy and Corticosteroid Treatment: Changing Conclusions without Changing Evidence

TO THE EDITOR:

The purpose of this letter is to draw attention to the misuse of the results of some clinical studies. I refer to a study published in Annals in June 1994 [1]. The aim of this study was to determine whether corticosteroids affect the findings in temporal artery biopsy in patients with temporal arteritis. The authors retrospectively reviewed the charts of 535 patients who underwent temporal biopsy. Each specimen was reexamined by a pathologist. However, every decision about treatment was based on clinical grounds, and there was no gold standard for the diagnosis other than the biopsy result. Biopsy results were positive in 31% of all patients. Therefore, an undetermined number of patients had diseases other than temporal arteritis, and most of these patients were probably included in the nontreatment group because they were statistically less likely to have headache, jaw claudication, visual symptoms, and polymyalgia rheumatica. Even the adjustment for clinical variables would not suffice if different populations are being considered. Thus, the authors' conclusion that treated and untreated patients had similar biopsy findings [1] must be viewed with extreme caution. In the original report the authors did so, and they recognized that “these results do not prove that histologic features are unaffected by corticosteroids.”