Phalangeal quantitative ultrasound technology and dual energy X-ray densitometry in patients with primary hyperparathyroidism: influence of sex and menopausal status

Fifty-one patients with surgically proven primary hyperparathyroidism (PHPT), 11 males and 40 females, mean age±SD: 55.9±14.1 years, and 58 age- and sex-matched normal subjects were studied. The femoral and L₂–L₄ bone mineral density (BMD; Hologic QDR 4500 C), as well as quantitative ultrasonometry (QUS; DBM-Sonic 1200) of the phalanges of both hands were measured in patients and controls. QUS measurements included amplitude-dependent speed of sound (AD-SoS), and other parameters derived from the graphic trace: signal dynamics (Sdy), first wave amplitude (FWA), bone transmission time (BTT) and ultrasound bone profile index (UBPI). Patients with PHPT showed significantly lower dual energy X-ray densitometry (DXA) values and QUS parameters compared to controls (lumbar spine Z-score: controls: −0.16±1.12, PHPT: −0.70±1.14, P=0.016 ; femoral neck Z-score: controls: −0.28±1.74, PHPT: −1±1.01, P=0.013 ; total femur Z-score: controls: −0.33±1.12, PHPT: −1.01±0.95, P=0.0013; AD-SoS Z-score: controls: −0.89±1.22, PHPT: −1.97±1.78, P=0.0003; FWA Z-score: controls: 0.36±1, PHPT: 0.62±0.85, P<0.0001; BTT Z-score: controls: 0.04±1.03, PHPT: −0.45±1.37, P=0.044; UBPI Z-score: controls: −0.02±1.01, PHPT: −0.68±1.05, P=0.002; SDy (mV/μs²): controls: −295±256, PHPT: −498±306, P=0.0003). In male patients, BMD values measured on the lumbar spine and femoral regions were similar to those found in male controls, while QUS values were significantly lower (lumbar spine Z-score: controls: −1.05±1.41, PHPT: −1.75±1.21, P=0.21; femoral neck Z-score: controls: −0.37±1.84, PHPT: −1.11±1.14, P=0.27; total femur Z-score: controls: −0.16±1.59, PHPT: −1.02±1.20, P=0.168; AD-SoS Z-score: controls: −0.52±1.58, PHPT: −1.57±1.77, P=0.149; FWA Z-score: controls: 0.67±1.01, PHPT: −0.74±0.79, P=0.0016; BTT Z-score: controls: 1.22±0.83, PHPT: 0.75±1.51, P=0.478; UBPI Z-score: controls: 0.56±0.94, PHPT: −0.47±1.10, P=0.025; SDy (mV/μs²): controls: −167±230, PHPT: −485±307, P=0.01). Women with PHPT were further divided into two subgroups: premenopause (n=11) and postmenopause (n=29). The premenopausal women with PHPT showed significantly lower DXA values than those of the premenopausal control ones, but similar QUS parameters (lumbar spine Z-score: controls: 0.12±0.66, PHPT: −0.59±0.85, P=0.03; femoral neck Z-score: controls: 0.06±2.85, PHPT: −1.48±1.05, P=0.11; total femur Z-score: controls: −0.51±0.97, PHPT: −1.48±0.63, P=0.009; AD-SoS Z-score: controls: 0.78±0.89, PHPT: −1.26±1.88, P=0.42; FWA Z-score: controls: 1.14±0.77, PHPT: 0.12±0.80, P=0.007; BTT Z-score: controls: 0.13±0.60, PHPT: 0.25±1.15, P=0.757; UBPI Z-score: controls: 0.73±0.49, PHPT: 0.24±0.96, P=0.15; SDy (mV/μs²): controls: −118±123, PHPT: −271±301, P=0.106). The postmenopausal women with PHPT showed both DXA and QUS parameters significantly lower than those found in the postmenopausal controls (lumbar spine Z-score: controls: 0.09±0.96, PHPT: −0.31±0.96, P=0.004; femoral neck Z-score: controls: −0.38±1.01, PHPT: −0.76±0.91, P=0.14; total femur Z-score: controls: −0.33±0.97, PHPT: −0.81±0.92, P=0.057; AD-SoS Z-score: controls: −1.08±1.17, PHPT: −2.38±1.68, P=0.31; FWA Z-score: controls: −0.013±0.81, PHPT: −0.86±0.74, P=0.0009; BTT Z-score: controls: −0.58±0.68, PHPT: −1.13±0.93, P=0.016; UBPI Z-score: controls: −0.62±0.83, PHPT: −1.11±0.82, P=0.034; SDy (mV/μs²): controls: −419±242, PHPT: -589±269, P=0.012). The relative risk of osteopenia was significantly increased in PHPT patients at several measurement sites. There was a highly significant correlation between spine and femoral BMD and QUS parameters, while PTH serum levels did not correlate with any of the densitometric variables. In conclusion, QUS parameters would seem to be able to distinguish patients with PHPT from normal controls in male subjects and in postmenopausal women, but not in premenopausal women. This would suggest that the higher estrogen levels in premenopausal patients might preserve the bone from significant structural changes. This may also suggest that hyperparathyroidism, in addition to the reduction of bone mineral content, can cause an alteration of bone structure with an additional increase in fracture risk in postmenopausal women. Furthermore, the alterations in QUS parameters in patients who do not show significant changes in DXA measurements suggest an involvement of bone that is independent of mineral content and may be helpful for selecting candidates for surgery, according to NIH criteria.