Table 4. Intra- and interobserver reliability for fracture presence, worst fracture grade, cumulative fracture grade and vertebral height loss.

Level	Outcome	Measure	Reliability
			Observer	1	2	3	4
Patient	Fracture present	Kappa	1	0.73 (0.52–0.91)	0.75 (0.50–91)	0.67 (0.42–0.88)	0.56 (0.29–0.79)
			2		0.84 (0.63–1)	0.61 (0.34–0.83)	0.59 (0.29–0.82)
			3			0.78 (0.58–0.96)	0.81 (0.61–0.96)
			4				0.76 (0.52–0.95)
Patient	Worst fracture grade *	Weighted kappa *	1	0.84 (0.68–0.93)	0.85 (0.67–0.95)	0.79 (0.56–0.92)	0.73 (0.45–0.88)
			2		0.89 (0.75–0.98)	0.82 (0.58–0.92)	0.87 (0.65–0.94)
			3			0.9 (0.78–0.96)	0.88 (0.67–0.97)
			4				0.89 (0.71–0.96)
Patient	Cumulative fracture grade	ICC **	1	0.91 (0.54–0.97)	0.75 (0.61–0.96)	0.94 (0.57–0.98)	0.87 (0.45–0.93)
			2		0.84 (0.71–0.94)	0.74 (0.57–0.93)	0.87 (0.48–0.96)
			3			0.91 (0.76–0.95)	0.89 (0.56–0.94)
			4				0.94 (0.65–0.98)
Vertebral	Height loss (%)	ICC **	1	0.9 (0.81–0.95)	0.82 (0.62–0.92)	0.81 (0.65–0.90)	0.56 (0.27–0.75)
			2		0.75 (0.48–0.91)	0.7 (0.42–0.85)	0.53 (0.21–0.73)
			3			0.82 (0.68–0.90)	0.55 (0.29–0.73)
			4				0.59 (0.33–0.77)
Vertebral	Fracture present	Kappa	1	0.72 (0.58–0.85)	0.63 (0.43–0.79)	0.58 (0.41–0.73)	0.43 (0.24–0.59)
			2		0.74 (0.55–0.88)	0.57 (0.37–0.73)	0.39 (0.18–0.58)
			3			0.71 (0.57–0.82)	0.51 (0.32–0.67)
			4				0.56 (0.38–0.71)

Bold and italic = intra-observer.

^*Square-weighted kappa.

^**The Intraclass Correlation Coefficient (ICC).

(95% confidence intervals based on 2000 bootstrap replicates).