Osteoporosis among Fallers without Concomitant Fracture Identified in an Emergency Department: Frequencies and Risk Factors

Table 3

The ability of two selected factors to correctly identify fallers with osteoporosis. Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs).

Associated factor	True positive (TP)	True negative (TN)	False positive (FP)	False negative (FN)	Sensitivity	Specificity	PPV (95% CI)	NPV (95% CI)
Body height reduction (self-reported)	32	91	67	9	78	58	32 (28–36)	91 (89–93)
Previous fracture (osteoporotic localisation)	13	135	23	28	32	85	36 (27–45)	82 (64–100)
Self-reported body-height reduction>3 cm and/or fracture	35	77	81	6	85	49	30 (27–34)	93 (92–94)

Sensitivity = TP/(TP+FN): ability to correctly identify osteoporotic fallers.
Specificity = TN/(TN+FP): ability to correctly exclude fallers with normal BMD/osteopenia.
PPV = TP/(TP+FP).
NPV = TN/(TN+FN).