Calcaneal quantitative ultrasound and Phalangeal radiographic absorptiometry alone or in combination in a triage approach for assessment of osteoporosis: a study of older women with a high prevalence of falls

Table 5 Application of UK-NOS triage approach combining phalangeal RA and calcaneal QUS

Combined test phalangeal RA and Calcaneal QUS (n = 202)	UK-NOS triage approach 85% certainty level	95% CI	UK-NOS triage approach 90% certainty level	95% CI	UK-NOS triage approach 95% certainty level	95% CI
RA T-score, upper/lower cutoff	-1.36/–2.52	NA	-0.65/–2.75	NA	0.28/–3.32	NA
QUS BUA, upper/lower cutoff	101.74/89.63	NA	105.88/86.63	NA	114.5/80.09
Sensitivity (%)	98.9	94.1–100	100	96.1–100	100	96.1–100
Specificity (%)	95.5	89.7–98.5	99.1	95.0–100	100	96.7–100
PPV (%)	87.2	72.6–95.7	94.7	74.0–99.9	100	54.1–100
NPV (%)	97.5	86.8–99.9	100	86.3–100	100	75.3–100
False negative (%)	0.5	0.01–2.7	0	0–0.2	0	0–3.2
False positive (%)	2.5	0.8–5.7	0.5	0.01–2.7	0	0–3.9
DXA scans avoided (%)	41.1	34.2-48.2	21.8	16.3–28.1	9.4	6.2–14.9

Application of UK-NOS triage approach combining phalangeal RA and calcaneal QUS at a certainty level of 85%, 90%, or 95% for each method. Abbreviations: QUS Quantitative Ultrasound, BUA Broadband Ultrasound Attenuation, RA Radiographic Absorptiometry, UK-NOS United Kingdom National Osteoporosis Society, PPV Positive Predictive Value, NPV Negative Predictive Value, DXA Dual Energy X-ray Absorptiometry, CI Confidence Interval, NA not available.