Bone Mineral Density Response to Long-Term Bisphosphonate Treatment and Discontinuation in a Real-World Clinical Service.

OBJECTIVE: Bisphosphonate treatment does not increase bone mineral density (BMD) in all subjects particularly at the femoral neck (FN). Our aim was to evaluate the relationship between response to oral bisphosphonate (oBP) at the FN and change in BMD following discontinuation. METHODS: Data were collected retrospectively from postmenopausal women on oBP for ≥3 years, attending a real-world metabolic clinic at initiation of oBP, discontinuation, and 1 to 2 years post discontinuation. Improvement in BMD ≥4% in the FN and ≥5% for the lumbar spine (LS) were deemed clinically meaningful and used as least significant change (LSC) values. We divided subjects based on FN BMD response and compared outcomes between responders and non-responders after oBP discontinuation. RESULTS: Of the 213 subjects, 32.1% showed an increase ≥LSC at the FN compared to 57.1% at the LS on treatment (P < .0001). FN responders had lower BMD levels at pretreatment baseline than non-responders both at the FN (0.58 vs 0.62 g/cm2; P = .003) and LS (0.76 vs 0.79 g/cm2; P = .044). Off-treatment, more subjects lost BMD ≥LSC at FN in the responder group than in the non-responder group (37.5% vs 14.2%; P < .001). BMD remained above pre-treatment levels in responders after a median follow-up of 1.52 years. CONCLUSION: BMD response at FN is suboptimal in patients on oBP and is much less common than LS response. FN responders tend to lose the accumulated bone quickly off-treatment, though BMD remains above pretreatment levels. These observations suggest that new approaches may be needed to optimize osteoporosis management in real-world patients.

Does anastrozole affect bone resorption similarly in early and late postmenopausal women?

The aim of this study was to determine whether the bone-resorption response to anastrozole differed according to initial patient age in postmenopausal women with breast cancer in a cross-sectional study. Second-morning void urines were collected for measurement of urinary cross-linked N-telopeptide of type I collagen (uNTx, corrected for creatinine and log-transformed) from postmenopausal women, 99 with breast cancer on anastrozole (ABC), 88 with newly diagnosed breast cancer (NDBC), and 137 community-dwelling healthy control (HC) women. Bone mineral density (BMD) was also measured at the lumbar spine (LS, L2-L4) and the femoral neck (FN) in the ABC group. uNTx (nanomole bone collagen equivalents/millimole creatinine) levels increased with age in HC subjects. In patients <70 years, anastrozole treatment led to a significant increase in uNTx compared with age-related HC subjects (1.74 vs. 1.55, P < 0.005). Patients >70 years showed no such increase compared to HC (1.72 vs. 1.69, nonsignificant); however, NDBC women >70 years had uNTx levels significantly lower than HC women (1.59 vs. 1.69, P < 0.05). There was no difference in uNTx levels above and below the age of 70 years in NDBC women (1.56 vs. 1.59, nonsignificant). ABC women were more likely to have a positive LS BMD z score than age-matched controls. Anastrozole treatment increases bone turnover more in younger postmenopausal women with breast cancer than in older women compared to healthy controls. Higher LS BMD in ABC patients may help protect against fracture.

Increased circulating Dickkopf-1 in Paget's disease of bone.

UNLABELLED: Dickkopf-1 (Dkk-1) is a secreted inhibitor of Wnt signaling which in adults regulates bone turnover. Dkk-1 over-production is implicated in osteolytic disease where it inhibits bone formation and stimulates bone breakdown. Recently it was reported that osteoblastic cells from Paget's disease of bone (PDB) over-expressed Dkk-1. OBJECTIVE: To see if increased Dkk-1 was detected in serum from patients with PDB. RESULTS: Dkk-1 and total serum alkaline phosphatase activity (tsAP) were significantly elevated in sera from PDB patients. Patients with polyostotic PDB had significantly higher levels of tsAP but not Dkk-1, than monostotic patients. TsAP but not Dkk-1, was significantly lower in sera from bisphosphonate treated versus untreated PDB patients. Dkk-1 and tsAP were not significantly correlated. CONCLUSIONS: Dkk-1 may be a useful biomarker of PDB and we speculate that Dkk-1 may play a central role in the etiology of PDB.

Bone resorption in stroke and institutionalized subjects.

Stroke increases the risk of hip fracture on the affected side. Although bone is lost by 1 year, rapidity of onset and relationship with immobility are uncertain. Using the bone resorption marker urinary cross-linked N telopeptide of type I collagen (uNTx), we examined bone resorption in the first 4 weeks after stroke, relating uNTx with bone density and mobility in subjects over 60 years. Two separate control groups acted as comparators, healthy (HC) and institutionalized (IC) controls, the latter to control for the effects of institutionalization. uNTx, urinary calcium (both related to creatinine and log-transformed), heel bone mineral density (BMD), Tinetti scores, and Barthel scores for prestroke function were measured. Log uNTx/Cr was lower in males compared with females, but this difference was not evident in stroke or IC subjects. Log uNTx/Cr was inversely related with BMD in females from both control groups and in male stroke subjects. Tinetti scores were divided into tertiles and were lower in stroke than IC subjects (P < 0.01). Log uNTx/Cr was similar in stroke and IC subjects in the lowest Tinetti tertile. Log uNTx/Cr was higher in stroke subjects of both sexes in the lowest tertile compared with the higher two tertiles combined (P < 0.05) and higher in all tertiles compared with HC subjects (P < 0.05). Subjects with a prestroke Barthel index of < or = 17 had higher log uNTx/Cr compared with HCs. Log uCa/Cr was higher only in male stroke patients. Bone resorption in stroke starts early, and measures to reduce this are merited.

Assessment of urinary bone markers for monitoring treatment of osteoporosis.

BACKGROUND: The usefulness of urinary markers of bone turnover in monitoring therapy depends on their within-person variability compared with their responses to therapy. The aim of this study was to assess the performance of two such markers on this basis. METHODS: We measured variation, during a whole year, of cross-linked N-terminal telopeptide of collagen I (NTx) and urinary deoxypyridinoline (DPD) as ratios to creatinine concentration and after log-transformation of the ratios in untreated women stratified into three bone density classes, of which the lowest was osteoporotic. We also measured changes in bone mineral density at the lumbar spine (LSBMD) and hip (FNBMD) in untreated women with normal bones and in those with moderate osteopenia and calculated the reference change value (RCV; or least significant change) at P <0.05 for all of these measures. We made the same measurements on women treated with bisphosphonates, estrogen replacement (HRT), or calcium and examined their individual responses to treatment compared with RCV. RESULTS: After 12 months on bisphosphonates, LSBMD changed more than RCV (2.55%) in 47% of women compared with 44% of those on HRT and 13% of those on calcium. Response of FNBMD was less. Log NTx (RCV= -28%) responded to bisphosphonates in 78%, regardless of BMD, but less often to HRT (67%). Log DPD (RCV= -30%) responded to bisphosphonates less frequently (31% at 12 months). CONCLUSIONS: NTx has advantages over DPD in monitoring therapy for osteoporosis when mailed urine samples are used.