Diagnostic Accuracy of Symptoms, Signs and Labs in GCA Save

A systematic review and meta-analysis of 68 diagnostic cohort studies (14 037 patients) suggests that no one feature is more impactful that the combination of symptoms, signs, and laboratory tests to diagnose the presence giant cell arteritis (GCA).

From these analyses findings associated with a diagnosis of GCA included: 

• Limb claudication (positive LR, 6.01; 95% CI, 1.38-26.16)
• Jaw claudication (positive LR, 4.90; 95% CI, 3.74-6.41)
• Temporal artery thickening (positive LR, 4.70; 95% CI, 2.65-8.33)
• Temporal artery loss of pulse (positive LR, 3.25; 95% CI, 2.49-4.23)
• Platelet count of >400K (positive LR, 3.75; 95% CI, 2.12-6.64)
• Temporal tenderness (positive LR, 3.14; 95% CI, 1.14-8.65)
• ESR >100 mm/h (positive LR, 3.11; 95% CI, 1.43-6.78)

Findings not associated with GCA included:

• Absence of ESR > 40 mm/h (negative LR, 0.18; 95% CI, 0.08-0.44)
• Absence of CRP > 2.5 mg/dL (negative LR, 0.38; 95% CI, 0.25-0.59)
• Absence of age >70 years (negative LR, 0.48; 95% CI, 0.27-0.86).

They concluded that further investigations, such as vascular imaging, temporal artery biopsy, were best when seeking evaluation for alternative diagnoses.