Effects of Treatment with Parathyroid Hormone 1–84 on Quantity and Biomechanical Properties of Thoracic Vertebral Trabecular Bone in Ovariectomized Rhesus Monkeys

Osteoporosis is characterized by impaired bone quality leading to increased susceptibility to fracture, particularly of the thoracic spine. However, the lumbar spine is studied most commonly. We investigated the effects of 16 months of treatment with full-length parathyroid hormone (PTH) 1–84 (5, 10, or 25 μg/kg) on bone mineral density (BMD) and on architecture and biomechanical properties of trabecular bone at the thoracic spine of ovariectomized (OVX) adult rhesus monkeys and compared the results with those from the lumbar spine. At baseline, 9 months after surgery, dual-energy X-ray absorptiometric BMD at T9–T12 was 7% lower in OVX than in sham animals. All PTH(1–84) doses increased BMD to sham levels within 7 months. Micro-computed tomography of T10 vertebrae showed that trabecular bone volume and connectivity were higher in PTH(1–84)-treated animals than in sham controls, primarily through a significantly greater trabecular number. Peripheral quantitative computed tomography of trabecular bone cores from T11 and T12 confirmed that PTH(1–84) increased BMD. Compression testing of the cores showed that PTH(1–84) treatment increased stiffness, modulus, yield load, and yield stress to levels significantly greater than in sham animals, with the largest effect in the 10 μg/kg group (35–54% greater than in OVX controls). Thus, PTH(1–84) treatment increased BMD and the biomechanical properties of trabecular bone at the thoracic spine of OVX rhesus monkeys. The 10 μg/kg dose produced the greatest effect on trabecular strength, possibly because the highest dose stimulated bone remodeling excessively. Importantly, the changes observed were similar to those in lumbar vertebrae, thereby validating extrapolation of results from the lumbar to the thoracic spine.     

Circulating Fibroblast Growth Factor-23 Increases Following Intermittent Parathyroid Hormone (1–34) in Postmenopausal Osteoporosis: Association with Biomarker of Bone Formation

Uncertainties exist regarding whether FGF-23 production is influenced by PTH and its involvement in bone formation. We evaluated FGF-23 response and its relation to changes in biomarkers of bone formation following intermittent PTH treatment. Twenty-seven women with a mean [SD] age of 75.8 [5.4] years with postmenopausal osteoporosis were treated with PTH(1–34) for 18 months. Bone mineral density (BMD) was measured at 6 and 18 months at the lumbar spine (LS) and total hip (TH). Blood samples were obtained at baseline, 1–3, 6–9, and 12–18 months. Serum calcium, phosphate, PTH, 25(OH)vitamin D, 1,25(OH)₂vitamin D, markers of bone turnover, FGF-23, and sclerostin were measured. BMD increased at both the LS (11.6%, P < 0.001) and TH (2.5%, P < 0.01). The bone formation marker P1NP increased early (baseline mean [SD] 39.9 [24.4] μg/l, 1–3 months 88 [37.9] μg/l; P < 0.001) and remained higher than baseline throughout 18 months. FGF-23 also increased, with a peak response at 6–9 months (increase 65%, P = 0.002). Serum phosphate remained stable. A significant increase in 1.25(OH)₂vitamin D (P = 0.02) was seen at 1–3 months only. A small but significant reduction in sclerostin was seen at 6–9 (P = 0.02) and 12–18 months (P = 0.06). There was a positive correlation between changes in P1NP and FGF-23 (6–9 months r = 0.78, P < 0.001). FGF-23 is increased by intermittent PTH(1–34). This is related to early changes in P1NP, suggesting that the skeletal effects of PTH may involve FGF-23. Further studies are required to elucidate this.     

Long-Term Continuous Combined Hormone Replacement Therapy in the Prevention of Postmenopausal Bone Loss: A Comparison of High- and Low-Dose Estrogen–Progestin Regimens

We studied the effect of four continuous combined estradiol valerate (E₂V) and medroxyprogesterone acetate (MPA) dose combinations in six treatment groups (n= 70 per group) receiving regimens containing 1 mg or 2 mg E₂V combined to 2.5 mg or 5 mg MPA, on bone mineral density (BMD) and endometrium in 419 healthy postmenopausal women over 4 treatment years. In two groups the 1 mg dose of E₂V was increased to 2 mg after the first 6 months, while the MPA doses remained constant (2.5 mg or 5 mg). The remaining four groups received 1 E₂V + 2.5 mg MPA, 1 mg E₂V + 5 mg MPA, 2 mg E₂V + 2.5 mg MPA, or 2 mg E₂V + 5 mg MPA throughout the study. BMD at the spine and hip was measured by dual-energy X-ray absorptiometry and endometrial biopsy samples were taken at 6, 12, 24, 36 and 48 month follow-ups. Combinations containing the low dose of 1 mg of E₂V (with 2.5 mg or 5 mg MPA) resulted in a mean BMD increase of 6.2% at the spine and 2.9% at the femoral neck after 4 years of treatment. With 2 mg E₂V the corresponding increases were 7.4% and 2.9%, respectively. The largest increases in BMD were seen in women for whom the E₂V dose was doubled after the initial 6 months of treatment: 8.9% at the spine and 4.2% in the femoral neck. Both MPA doses (2.5 mg and 5 mg) effectively prevented estrogen-induced stimulation of the endometrium. No endometrial hyperplasia was observed in any of the treatment groups. Lower-dose combinations of continuous combined estrogen–progestin regimens are effective in increasing and maintaining BMD and provide a good endometrial safety profile for the long-term prevention of osteoporosis in postmenopausal women. Received: 15 February 2000 / Accepted: 3 May 2000     

Polymorphisms in the CYP19 and AR Genes—Relation to Bone Mass and Longitudinal Bone Changes in Postmenopausal Women With or Without Hormone Replacement Therapy: The Danish Osteoporosis Prevention Study

Polymorphisms in the androgen receptor (AR) gene and genes encoding enzymes involved in synthesis of sex steroids (e.g., the CYP19 gene encoding aromatase) have recently received attention in osteoporosis research. In the Danish Osteoporosis Prevention Study, recent postmenopausal women were allocated to either hormone replacement therapy (HRT) or no treatment. We genotyped 1792 women for the CYP19 (TTTA)_n repeat [short (TTTA)_{n 7} or long (TTTA)_{n > 7}] the CYP19 C¹⁵⁵⁸-T, and the AR (CAG)_n repeat polymorphism [short (CAG)_{n < 22}, long (CAG)_{n 22}], and investigated associations with bone mineral density (BMD) and 5-year change in BMD. The CYP19 polymorphisms were in strong linkage disequilibrium. Perimenopausal bone mass or bone loss in untreated women was not associated with the CYP19 polymorphisms. In hormone-treated women, BMD increase in the femoral neck was highest (+0.3%/year) for long CYP19 alleles, lowest (–0.09%/year) for short alleles, and intermediate (–0.002%/year) in heterozygous women, P = 0.015. Differences were also significant in the lumbar spine, total hip, and ultradistal forearm. The C¹⁵⁵⁸-T T-allele was associated with a more pronounced response to HRT (P = 0.04, total hip). AR genotype was not related to BMD, but a modifying effect of sex hormone-binding globulin (SHBG) was present. In the highest SHBG quartile (SHBG > 95 nmol/1, n = 222), AR genotype was associated with baseline BMD (femoral neck: P < 0.001, total hip: P = 0.008), but without a clear gene dosage effect. We have demonstrated that polymorphisms in the CYP19 gene are associated with the magnitude of bone gain in response to HRT and that the (CAG)_n repeat polymorphism in the AR gene is associated with bone mass in women with high levels of SHBG. These findings emphasize the complexity of the genetics of bone mass and bone loss. Data was presented in part at the 30th European Symposium on Calcified Tissues, Rome, Italy, May 2003.     

Polymorphisms in the CYP19 and AR Genes—Relation to Bone Mass and Longitudinal Bone Changes in Postmenopausal Women With or Without Hormone Replacement Therapy: The Danish Osteoporosis Prevention Study

Polymorphisms in the androgen receptor ( AR) gene and genes encoding enzymes involved in synthesis of sex steroids (e.g., the CYP19 gene encoding aromatase) have recently received attention in osteoporosis research. In the Danish Osteoporosis Prevention Study, recent postmenopausal women were allocated to either hormone replacement therapy (HRT) or no treatment. We genotyped 1792 women for the CYP19 (TTTA)(n) repeat [short (TTTA)(n 7)] the CYP19 C(1558)-T, and the AR (CAG)(n) repeat polymorphism [short (CAG)(n < 22), long (CAG)(n >or= 22)], and investigated associations with bone mineral density (BMD) and 5-year change in BMD. The CYP19 polymorphisms were in strong linkage disequilibrium. Perimenopausal bone mass or bone loss in untreated women was not associated with the CYP19 polymorphisms. In hormone-treated women, BMD increase in the femoral neck was highest (+0.3%/year) for long CYP19 alleles, lowest (-0.09%/year) for short alleles, and intermediate (-0.002%/year) in heterozygous women, P = 0.015. Differences were also significant in the lumbar spine, total hip, and ultradistal forearm. The C(1558)-T T-allele was associated with a more pronounced response to HRT ( P = 0.04, total hip). AR genotype was not related to BMD, but a modifying effect of sex hormone-binding globulin (SHBG) was present. In the highest SHBG quartile (SHBG > 95 nmol/1, n = 222), AR genotype was associated with baseline BMD (femoral neck: P < 0.001, total hip: P = 0.008), but without a clear gene dosage effect. We have demonstrated that polymorphisms in the CYP19 gene are associated with the magnitude of bone gain in response to HRT and that the (CAG)(n) repeat polymorphism in the AR gene is associated with bone mass in women with high levels of SHBG. These findings emphasize the complexity of the genetics of bone mass and bone loss.     

Histomorphometric Evaluation of the Recovering Effect of Human Parathyroid Hormone (1–34) on Bone Structure and Turnover in Streptozotocin-Induced Diabetic Rats

The purpose of this study was to determine whether human parathyroid hormone (h-PTH) enhances trabecular bone mass and connectivities that were reduced by streptozotocin (STZ)-induced diabetes in rats. Seven-month-old female Wistar rats were injected with STZ or its vehicle intraperitoneally. All vehicle-injected normal controls were sacrificed 0, 4, 6, 8, 12, 14, and 16 weeks after injection, and one-third of the STZ-injected rats were sacrificed as the baseline controls 4, 6, and 8 weeks after the injection. Eight-week h-PTH (6.0 μg/kg, 6 times a week) or its vehicle treatment by subcutaneous injection for residual diabetic rats was started 4, 6, or 8 weeks after the STZ injection. The rats' proximal right tibiae were processed for undecalcified Villanueva bone staining sections for bone histomorphometry. Furthermore, changes in trabecular connectivities were determined by node-strut analysis. The decreased cancellous bone volume (BV/TV) and turnover in diabetic rats were recovered in all PTH-treated groups. In node-strut analysis, the node-related parameters (N.Nd/TV, NdNd/TV) were significantly increased by PTH when it was administered 4 weeks after STZ injection but were not increased when administration was started after 6 weeks. The results indicated that PTH enhanced bone turnover and bone mass but not trabecular connectivity in the late stage of diabetes in rats. Early treatment of osteoporosis is important in preventing fractures caused by decreased bone strength resulting from decreased trabecular connectivity. Received: 11 May 1999 / Accepted: 20 September 1999     

A Combination of Low Doses of 17β-Estradiol and Norethisterone Acetate Prevents Bone Loss and Normalizes Bone Turnover in Postmenopausal Women

The effects of 17β-estradiol (E₂) 1 mg combined with low doses of norethisterone acetate (NETA) on postmenopausal bone loss and turnover were investigated in a 2-year, randomized, double-masked, placebo-controlled trial. A total of 135 postmenopausal women with a lumbar spine bone mineral density (BMD) T-score between −2 and +2 were randomized to daily treatment with an oral tablet of either placebo, E₂ 1 mg/NETA 0.25 mg, or E₂ 1 mg/NETA 0.5 mg. Significant (p<0.001) increases in BMD at the lumbar spine (L1–4) were observed with E₂ 1 mg/NETA 0.25 mg (5.2%) and E₂ 1 mg/NETA 0.5 mg (5.4%) compared with placebo (−0.9%). The total hip BMD increased significantly in the E₂ 1 mg/NETA 0.25 mg (3.1%) and E₂ 1 mg/NETA 0.5 mg groups (3.3%) compared with placebo. At the femoral trochanter, the increase in BMD in the E₂ 1 mg/NETA 0.5 mg group (6.3%) was significantly different from the placebo group (0.8%), while that in the E₂ 1 mg/NETA 0.25 mg group (3.3%) was not. No statistical differences were found between the active groups and placebo for the change in BMD at the femoral neck. Significant increases in BMD at the distal radius and total body were found for both E₂ 1 mg/NETA 0.25 mg (0.9% and 2.5%, respectively) and E₂ 1 mg/NETA 0.5 mg (2.1% and 3.0%, respectively) compared with placebo (−0.7% and 0.4%, respectively).  At the end of the treatment, urinary pyridinoline type I collagen C-telopeptide had decreased by 65% and 60% in the E₂ 1 mg/NETA 0.25 mg and E₂ 1 mg/NETA 0.5 mg groups, respectively, while the mean serum concentrations of osteocalcin had decreased by 39% and 34%, bone-specific alkaline phosphatase by 32% and 29%, and C-terminal propeptide of type I collagen by 21% and 19% had decreased by 34-39%, 29-32%, and 19-21% in the E₂ 1 mg/NETA 0.25 mg and E₂ 1 mg/NETA 0.25 mg groups, respectively.  In conclusion, combinations of E₂ 1 mg and NETA 0.25 or 0.5 mg prevent bone loss in postmenopausal women at the lumbar spine, hip, distal radius and total body, and normalize bone turnover. Received: 12 March 1998 / Accepted: 31 August 1999     

Vertebral Bone Mineral Density, Content and Area in 8789 Normal Women Aged 33–73 Years Who Have Never Had Hormone Replacement Therapy

The vertebral bone mineral density (BMD), bone mineral content (BMC) and bone area of the lumbar spine were measured using a bone densitometer in 8789 women aged 33–73 years who had had no previous hormone replacement therapy (HRT). The overall relationship between BMD and age was analyzed on a year-by-year basis, and comprised three separate regions that could each be described by a straight line: 33–46 years (gradient = 0.00166 g cm⁻²/year), 47–63 years (gradient = 0.0121 g cm⁻²/year) and 64–73 years (gradient = 0.0045 g cm⁻²/year). Above the age of 50 years our results were higher than the BMD in most previous reports. In those 3198 women who knew the time of their last menstrual period (mean age 49.25 years, SD 4.83) bone loss was most rapid in the first 10 menopausal years. In the whole group, the relationship between BMC and age was found to be similar to that of BMD, with three distinct regions, including a rapid drop between the ages of 47 and 63 years (gradient 0.781 g/year). Bone area showed a much more gradual (though significant) decrease with age. Based on WHO definitions and using BMD as an indicator, the percentage of women with osteoporosis varied from zero in the younger age group to about 30% of women aged over 70 years; in contrast, where BMC was used, although the trend with age had a similar shape, the percentages at each year were about half those derived from the corresponding BMD values. Osteopenia derived in the same way occurred in about 50% of women over 70 years using either BMD or BMC. The results presented here provide a reliable local reference range for lumbar spine bone densitometry measurements. They also show that for this site BMD and BMC cannot be used interchangeably to define osteoporosis. Received: 13 March 1998 / Accepted: 23 September 1998     

Pharmacokinetics of Teriparatide (rhPTH[1–34]) and Calcium Pharmacodynamics in Postmenopausal Women with Osteoporosis

Teriparatide (rhPTH[1–34]) affects calcium metabolism in a pattern consistent with the known actions of endogenous parathyroid hormone (PTH). This report describes the pharmacokinetics and resulting serum calcium response to teriparatide in postmenopausal women with osteoporosis. Pharmacokinetic samples for this analysis were obtained from 360 women who participated in the Fracture Prevention Trial. Postmenopausal women with osteoporosis received daily subcutaneous injections of either teriparatide 20 μg (4.86 μmol) or placebo, median 21 months’ treatment. Serum teriparatide and calcium concentrations were measured throughout the study. An indirect-response model was developed to describe the pharmacokinetic–pharmacodynamic relationship between teriparatide concentrations and serum calcium response. The pharmacokinetics of teriparatide were characterized by rapid absorption (maximum concentration achieved within 30 min) and rapid elimination (half-life of 1 h), resulting in a total duration of exposure to the peptide of approximately 4 h. Teriparatide transiently increased serum calcium, with the maximum effect observed at approximately 4.25 h (median increase 0.4 mg/dl [0.1 mmol/l]). Calcium concentrations returned to predose levels by 16–24 h after each dose. Persistent hypercalcemia was not observed; one teriparatide 20 μg-treated patient had a predose serum calcium value above the normal range but <11.0 mg/dl (2.75 mmol/l). Following once-daily subcutaneous administration, teriparatide produces a modest but transient increase in serum calcium, consistent with the known effects of endogenous PTH on mineral metabolism. The excursion in serum calcium is brief, due to the short length of time that teriparatide concentrations are elevated.     

Impact of a Phone Follow-Up Program on Persistence with Teriparatide or PTH(1–84) Treatment

A follow-up program to help patients suffering from severe osteoporosis during their therapy with teriparatide or PTH(1–84) has been designed and performed. The objective of this study was to evaluate the 18-month persistence on these therapies in patients participating in the program. We enrolled 382 patients who started teriparatide or PTH(1–84) following this program and compared them with a historical cohort of 398 patients treated with the same therapies but who did not participate in any follow-up program. At the beginning of the therapy, nurses trained patients on self-injection. Patients received one phone call per week during the first month, then one phone call per month and per 3 months during the following 5 and 12 months, respectively. In every call, nurses helped patients to resolve any possible issues and collected adverse event information. The persistence rate of the group following the program was 85.6%, 8.2% higher than that of the group not following any program (77.4%). The log-rank test on persistence rates on therapy in patients enrolled and not enrolled in the program was performed; the difference was statistically significant (P = 0.006). Discontinuation in the follow-up program group occurred mainly at early stages of the treatment due to adverse events. Our results show that patients suffering from severe osteoporosis treated with teriparatide or PTH(1–84) and enrolled in a follow-up program have higher persistence rates than patients not following the program.     

The Prevention of Osteoporosis Using Sequential Low-Dose Hormone Replacement Therapy with Estradiol-17β and Dydrogesterone

Low-dose hormone replacement therapy (HRT) in postmenopausal women may produce fewer side-effects but its efficacy in the prevention of bone loss and osteoporosis is not established. To address this we compared the effect of 1 mg estradiol-17β with a 2 mg dose, in combination with cyclical dydrogesterone, in the prevention of postmenopausal bone loss. We conducted a multicenter double-masked prospective randomized, placebo-controlled study in 595 apparently healthy postmenopausal women randomized to either placebo, or continuous oral estradiol-17β 1 mg or 2 mg with sequential dydrogesterone for 2 years. The primary endpoint was the percentage change from baseline in bone mineral density (BMD) in the lumbar spine (LS) and femoral neck (FN) of actively treated groups compared with placebo. Women taking either 1 mg or 2 mg estradiol-17β showed a significant increase in BMD of the LS (mean ± SD, 5.2 ± 3.8% and 6.7 ± 4.0% respectively, both p <0.001) whilst BMD in the placebo group decreased (–1.9 ± 4.0%). Increases were also observed in FN BMD in both treated groups (2.7 ± 4.2% and 2.5 ± 5.2% respectively, both p <0.001) in contrast to the placebo group (–1.8 ± 4.8%). The oldest women showed the greatest treatment response. One milligram estradiol-17β in combination with dydrogesterone is effective in conserving LS and proximal femur bone mass, both of which are clinically important sites of osteoporotic fracture, and is as effective as 2 mg in preventing FN bone. The lower dose of estradiol-17β is a particularly suitable treatment for osteoporosis management in older women since it should minimize side-effects and improve the acceptability of HRT. Received: 19 June 2000 / Accepted: 26 October 2000     

Estrogen Receptor β Dinucleotide (CA) Repeat Polymorphism is Significantly Associated with Bone Mineral Density in Postmenopausal Women

Significant associations between the lengths of a highly polymorphic dinucleotide (CA) repeat located within the human estrogen receptor beta (ESR2) gene on chromosome 14, bone mineral density (BMD) and androgen levels have been reported previously in premenopausal women. We measured the size of this microsatellite repeat in 226 healthy women (60–98 years). After adjustment for age, body mass index, hormone replacement status, and other variables known to influence BMD, women with <25 CA repeats had significantly higher BMD measured in the total skeleton, lumbar spine, and femoral neck when compared with women having longer alleles. Women with shorter alleles also had higher circulating estrone and estradiol levels that approached statistical significance as compared with women harboring longer alleles after appropriate adjustments were performed in linear regression models. Women having both short and long CA repeats had BMD values in all regions of the skeleton that were midway between those found in women homozygous for longer or shorter repeat sizes. Because the ESR2 CA repeat size was neither associated with change in BMD nor serum levels of biochemical markers of bone turnover, it is likely that ESR2 CA repeat genotype is significantly linked to the attainment of peak bone mass in women.This work was supported by grants AG10149 and AG02049 from the National Institutes of Health.     

Two Single Nucleotide Polymorphisms in the <Emphasis Type="Italic">CYP</Emphasis>17 and <Emphasis Type="Italic">COMT</Emphasis> Genes—Relation to Bone Mass and Longitudinal Bone Changes in Postmenopausal Women with or without Hormone Replacement Therapy

Sex steroids are important physiologic regulators of bone mass, and genes regulating sex steroid production and metabolism are obvious as candidate genes for osteoporosis susceptibility. We present data from a study of 1795 recent postmenopausal women, assigned to either hormone replacement therapy (HRT) or no treatment and followed for 5 years. The association between bone mass measurements and two single nucleotide polymorphisms, a T (A1) to C (A2) transition in the 5-UTR of the cytochrome P450c17 (CYP17) gene and a G (Val) to A (Met) transition in exon 4 of the catechol-O-methyltransferase (COMT) gene, was evaluated. Association with CYP17 genotype was modified by body mass index (BMI). In lean women, individuals homozygous for the CYP17 A2 allele were 1 cm shorter and had lower baseline BMD (bone mineral density), BMC, and CSA (cross sectional area) in the spine and femoral neck than did other women (BMD spine A2A2: 0.975 g/cm² versus 1.011 g/cm² in A1A1 + A1A2, P = 0.002). Conversely, an adverse association with A2A2 and bone loss over 5 years seemed present only in overweight women, but differences were small. Response to HRT was not dependent on CYP17 genotype. COMT genotype was not associated with bone mass at baseline, bone loss in untreated women, or response to HRT. In conclusion, the A2 allele of the CYP17 T²⁷-C polymorphism is associated with reduced bone mass and bone size in lean perimenopausal women, whereas high BMI protects against this negative association. The COMT G¹⁹⁴⁷-A polymorphism is not associated with bone parameters in this study.Presented in part as an abstract for poster presentation at the 2nd International Workshop on the Genetics of Bone Metabolism and Disease, Davos, Switzerland, February 2003     

Adverse Reactions and Drug–Drug Interactions in the Management of Women with Postmenopausal Osteoporosis

The pharmacological management of disease should involve consideration of the balance between the beneficial effects of treatment on outcome and the probability of adverse effects. The aim of this review is to explore the risk of adverse drug reactions and drug–drug interactions with treatments for postmenopausal osteoporosis. We reviewed evidence for adverse reactions from regulatory documents, randomized controlled trials, pharmacovigilance surveys, and case series. Bisphosphonates are associated with gastrointestinal effects, musculoskeletal pain, and acute-phase reactions, as well as, very rarely, atrial fibrillation, atypical fracture, delayed fracture healing, osteonecrosis of the jaw, hypersensitivity reactions, and renal impairment. Cutaneous effects and osteonecrosis of the jaw are of concern for denosumab (both very rare), though there are no pharmacovigilance data for this agent yet. The selective estrogen receptor modulators are associated with hot flushes, leg cramps, and, very rarely, venous thromboembolism and stroke. Strontium ranelate has been linked to hypersensitivity reactions and venous thromboembolism (both very rare) and teriparatide with headache, nausea, dizziness, and limb pain. The solidity of the evidence base depends on the frequency of the reaction, and causality is not always easy to establish for the very rare adverse reactions. Drug–drug interactions are rare. Osteoporosis treatments are generally safe and well tolerated, though they are associated with a few very rare serious adverse reactions. While these are a cause for concern, the risk should be weighed against the benefits of treatment itself, i.e., the prevention of osteoporotic fracture.     

A Retrospective Case–Control Study Assessing the Role of Trabecular Bone Score in Postmenopausal Caucasian Women with Osteopenia: Analyzing the Odds of Vertebral Fracture

This case–control study assessed whether the trabecular bone score (TBS), determined from gray-level analysis of DXA images, might be of any diagnostic value, either alone or combined with bone mineral density (BMD), in the assessment of vertebral fracture risk among postmenopausal women with osteopenia. Of 243 postmenopausal Caucasian women, 50–80 years old, with BMD T-scores between –1.0 and –2.5, we identified 81 with osteoporosis-related vertebral fractures and compared them with 162 age-matched controls without fractures. Primary outcomes were BMD and TBS. For BMD, each incremental decrease in BMD was associated with an OR = 1.54 (95% CI = 1.17–2.03), and the AUC was 0.614 (0.550–0.676). For TBS, corresponding values were 2.53 (1.82–3.53) and 0.721 (0.660–0.777). The difference in the AUC for TBS vs. BMD was statistically significant (p = 0.020). The OR for (TBS + BMD) was 2.54 (1.86–3.47) and the AUC 0.732 (0.672–0.787). In conclusion, the TBS warrants a closer look to see whether it may be of clinical usefulness in the determination of fracture risk in postmenopausal osteopenic women.     

Changes in Skeletal Microstructure Through Four Continuous Years of rhPTH(1–84) Therapy in Hypoparathyroidism

Bone remodeling is reduced in hypoparathyroidism, resulting in increased areal bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) and abnormal skeletal indices by transiliac bone biopsy. We have now studied skeletal microstructure by high-resolution peripheral quantitative computed tomography (HR-pQCT) through 4 years of treatment with recombinant human PTH(1–84) (rhPTH[1–84]) in 33 patients with hypoparathyroidism (19 with postsurgical disease, 14 idiopathic). We calculated Z-scores for our cohort compared with previously published normative values. We report results at baseline and 1, 2, and 4 years of continuous therapy with rhPTH(1–84). The majority of patients (62%) took rhPTH(1–84) 100 μg every other day for the majority of the 4 years. At 48 months, areal bone density increased at the lumbar spine (+4.9% ± 0.9%) and femoral neck (+2.4% ± 0.9%), with declines at the total hip (−2.3% ± 0.8%) and ultradistal radius (−2.1% ± 0.7%) (p < .05 for all). By HR-pQCT, at the radius site, very similar to the ultradistal DXA site, total volumetric BMD declined from baseline but remained above normative values at 48 months (Z-score + 0.56). Cortical volumetric BMD was lower than normative controls at baseline at the radius and tibia (Z-scores −1.28 and − 1.69, respectively) and further declined at 48 months (−2.13 and − 2.56, respectively). Cortical porosity was higher than normative controls at baseline at the tibia (Z-score + 0.72) and increased through 48 months of therapy at both sites (Z-scores +1.80 and + 1.40, respectively). Failure load declined from baseline at both the radius and tibia, although remained higher than normative controls at 48 months (Z-scores +1.71 and + 1.17, respectively). This is the first report of noninvasive high-resolution imaging in a cohort of hypoparathyroid patients treated with any PTH therapy for this length of time. The results give insights into the effects of long-term rhPTH(1–84) in hypoparathyroidism. © 2020 American Society for Bone and Mineral Research.