Table 3.

The incidence of giant cell arteritis (GCA) in various populations and key features of underlying epidemiologic studies

Location (reference)	Time period	Inclusion criteria	Number of subjects (N)		Annual incidencea
			Biopsy-proven only	All casesb	Biopsy-proven only	All casesb
Norway (PS)	1972–2012	ACR 1990 criteria	528	792	11.2	16.7
Norway [11]	1992–1996	Clinical diagnosis	47	53	29.1	32.8
Norway [13]	1987–1994	Biopsy-proven only	66	NR	29.0	NR
Sweden [29]	1997–2010	Biopsy-proven only	840	NR	14.1	NR
Sweden [36]	1976–1995	Biopsy-proven only	665	NR	22.2	NR
Sweden [47]	1973–1975	Clinical diagnosis	74	126	16.8	28.6
Finland [46]	1969–1989	Biopsy-proven only	66	NR	7.2	NR
Denmark [38]	1982–1994	Clinical diagnosis	NR	NR	15.1	20.4
Iceland [7]	1984–1990	Clinical diagnosis	125	133	25.4	27.0
Minnesota, USA [9]	2000–2009	ACR 1990 criteria + radiologic criteriac	56	74	NR	19.8
New Zealand [6]	1996–2005	Biopsy-proven only	70	NR	12.7	NR
Israel [39]	1990–2009	ACR 1990 criteria	NR	140	NR	8.1
Italy [14]	1986–2012	Biopsy-proven only	285	NR	5.8	NR
Spain [40]	1981–2005	Biopsy-proven only	255	NR	10.1	NR
Turkey [41]	2002–2008	Clinical diagnosis	13	19	NR	1.1

PS present study, NR not reported, ACR American College of Rheumatology

^aMean annual incidence reported as cases per 100,000 population age ≥50 years

^bIncluding probable cases based on clinical diagnosis despite negative biopsy or in patients in whom biopsy was not performed

^cSeven patients were included based on radiologic criteria. These were all ≥50 years old with elevated erythrocyte sedimentation rate or C-reactive protein, and evidence of large-vessel vasculitis on angiographic computed tomography, angiographic magnetic resonance imaging or positron emission tomography