Changes in QUS and BMD measurements with antiresorptive therapy: a two-year longitudinal study

• Published in: Calcified tissue international 2001-09, Vol.69 (3), p.138-146
• Main Authors: Frost, M L, Blake, G M, Fogelman
• Format: Article
• Language: English
• Subjects: Bone Density; Bone Resorption - prevention & control; Calcaneus - diagnostic imaging; Diphosphonates - therapeutic use; Drug Therapy, Combination; Estrogen Replacement Therapy; Estrogens - therapeutic use; Female; Femur Neck - diagnostic imaging; Femur Neck - metabolism; Hip Joint - diagnostic imaging; Hip Joint - metabolism; Humans; Longitudinal Studies; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - metabolism; Middle Aged; Osteoporosis, Postmenopausal - diagnostic imaging; Osteoporosis, Postmenopausal - drug therapy; Osteoporosis, Postmenopausal - metabolism; Radiography; Reproducibility of Results; Treatment Outcome; Ultrasonography
• ISSN: 0171-967X; 1432-0827
• DOI: 10.1007/s002230020037

There is lack of consensus on whether quantitative ultrasound (QUS) measurements can be used to monitor response to therapy. The aim of this 2-year longitudinal study was to assess whether calcaneal QUS measurement variables respond to antiresorptive therapy and whether these measurements display adequate long-term precision to be useful for monitoring purposes. The study population consisted of 195 postmenopausal women divided into three groups: Group 1: 39 women treated with antiresorptive therapy who commenced treatment at baseline; Group 2: 25 women treated with antiresorptive therapy who had been on treatment for at least 2 years at baseline; Group 3: 131 women who did not taken estrogen, bisphosphonates, or calcium during the 2-year study period. Subjects had baseline and 12 and 24 months follow-up BMD measurements at the lumbar spine (LS), femoral neck (FN), and total hip (THIP) and calcaneal QUS measurements of broadband ultrasound attenuation (BUA) and speed of sound (SOS). BUA and SOS were combined to provide an estimate of heel BMD (Est heel BMD). For women in Group 1, all BMD and QUS measurement variables increased significantly from baseline after 2 years of treatment. For women in Group 2, only THIP BMD and BUA increased significantly after 2 years and the changes were less than those observed in Group 1 women. The overall treatment effect for each measurement variable, defined as the difference in the mean absolute changes between Groups I and 3 after 2 years, was 0.08, 0.03, and 0.04 g/cm2 for LS, FN, and THIP BMD, and for BUA, SOS, and Est heel BMD it was 5.8 dB/MHz, 13.1 m/sec, and 0.05 g/cm2, respectively. When the overall treatment effect was expressed in T-score units, the effect was greatest for LS BMD (0.65 T-score units) and lowest for FN BMD (0.31 T-score units). QUS measurement variables yielded intermediate values of 0.43- 0.52 T-score units. The average least significant change (LSC) was 0.38 T-score units for BMD measurements, whereas the LSC for QUS measurements was three times greater at approximately 1.20 T-score units. Ninety-four percent of the women in Group 1 showed changes in LS BMD that exceeded the LSC after two years, while the percentage was lower for the other measurement variables ranging from approximately 6% for FN BMD, SOS and Est heel BMD to 50% for THIP BMD. A lower percentage of women in Groups 2 and 3 displayed changes that exceeded the LSC for both BMD and QUS measurement variables. Changes in all QUS vari