Early changes in bone specific turnover markers during the healing process after vertebral fracture

Association between P1NP value and increases in bone mineral density in patients with postmenopausal osteoporosis treated with romosozumab

OBJECTIVES

The present study aimed to investigate the effectiveness of treatment with romosozumab for 1 year and association between bone turnover markers and changes in bone mineral density (BMD) in patients with postmenopausal osteoporosis.

METHODS

Participants were 53 treatment-naïve postmenopausal osteoporosis patients. Correlations of per cent changes (Δ) in lumbar (L) and total hip (TH) BMD 12 months after initiating romosozumab with baseline demographic factors and parameters of N-terminal propeptide of Type 1 collagen (P1NP) and tartrate-resistant acid phosphatase-5b at baseline and Months 1, 3, and 6 were assessed. Multiple regression analysis was performed on factors significantly correlated with ΔL-BMD and ΔTH-BMD at Month 12.

RESULTS

ΔL-BMD and ΔTH-BMD at Month 12 were 17.5% and 8.1%, respectively. Multiple regression analysis revealed that a high P1NP value at Month 3 predicted large increases in L-BMD and TH-BMD at Month 12. High total amount of P1NP values from baseline to Month 6 was associated with large increases in L-BMD and TH-BMD at Month 12 and was most strongly correlated with the P1NP value at Month 3.

CONCLUSIONS

A high P1NP value at Month 3 predicted large increases in both L-BMD and TH-BMD at Month 12 in postmenopausal osteoporosis patients treated with romosozumab.

Rapid Hypercalciuria Induction With Bone Formation Marker Reduction During Immobilization in Children

OBJECTIVE

To prospectively examine the occurrence of hypercalciuria and changes in bone metabolite markers in pediatric patients during immobilization.

METHODS

In total, 13 children with an orthopedic disease requiring immobilization longer than 2 weeks were enrolled. Blood samples were collected after breakfast. Urine samples were collected at the second voiding after waking. The urine calcium/creatinine (Ca/Cr) ratio and various bone metabolite parameters were measured before and every 1 to 4 weeks after the start of immobilization.

RESULTS

The median patient age was 7 years with a range of 2 to 13 years. Orthopedic diseases in the patients were dislocated hip joint (N = 7), slipped capital femoral epiphysis (N = 2), etc. The urine Ca/Cr ratio increased significantly within a week after immobilization (P < .01) and continued to increase for 2 more weeks. Once immobilization ended, the urine Ca/Cr ratio gradually decreased and returned to the normal range approximately 6 weeks after mobility was achieved (P < .01). Serum alkaline phosphatase (ALP) and bone-specific ALP significantly decreased after immobilization began (P < .01). After immobilization ended, the serum ALP returned to preimmobilization levels in 2 to 4 weeks (P < .01). Serum N-terminal telopeptides did not change significantly during immobilization.

CONCLUSION

The urine Ca/Cr ratio immediately increased after immobilization. In contrast to adults, bone formation markers in children decreased during immobilization, whereas bone resorption markers did not increase. To our knowledge, this study is the first to examine bone metabolism markers in children during immobilization.

Urinary N-Telopeptide Can Predict Pseudarthrosis After Anterior Cervical Decompression and Fusion: A Prospective Study

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To examine preoperative urinary cross-linked n-telopeptide (uNTx) and assess for association with fusion rates in patients undergoing single and multi-level anterior cervical decompression and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Although high rates of fusion have been reported for ACDF, the risk of pseudarthrosis remains substantial. An established marker of bone turnover, uNTx may prove useful as a predictor of fusion.

METHODS

Patients undergoing primary ACDF with allograft/plating technique from 2015 to 2017 by a single surgeon were consecutively enrolled and preoperative uNTx was collected. Patients undergoing revision, with creatinine >1.2, and with improperly-collected uNTx were excluded. Demographics, laboratory values, and fusion status were assessed at 6 months, 1 year, and 2 years postoperatively.

RESULTS

Of the 97 patients enrolled, 69 met inclusion criteria. Of included cases, 41%, 33%, 18%, and 8% underwent 1-, 2-, 3-, and 4-level ACDF, respectively. Overall, fusion rates were 37.3%, 70.9%, and 95.3% at 6 months, 1 year, and 2 years, respectively. uNTx was higher in the fusion group (31.1 vs. 22.2, P = 0.001) at 6 months and 1 year (30.0 vs. 21.0, P = 0.006), with no difference at 2 years. No differences were identified in the proportion of smokers, immunomodulatory agents, corpectomies, or fusion levels between groups. Multivariate regression analysis demonstrated that uNTx is an independent predictor of fusion (odds ratio, OR, 1.124, P = 0.003). Both groups experienced improvements in NDI and VAS neck pain at 6 months with no significant differences noted between groups. Of 16 patients with pseudarthrosis at 1 year, 2 underwent posterior cervical fusion for symptoms.

CONCLUSION

Preoperative uNTx was greater in patients with successful ACDF fusion compared with patients with pseudarthrosis at 6 months and 1 year. A negative correlation was found between preoperative uNTx and motion on dynamic imaging. These results suggest that uNTx could serve to identify patients at risk for pseudarthrosis after ACDF.

LEVEL OF EVIDENCE

3.

DIAGNOSIS OF ENDOCRINE DISEASE: Bone turnover markers: are they clinically useful?

Bone turnover markers (BTMs) are useful in clinical practice as they are inexpensive, and they have proven useful for treatment monitoring and identification of poor adherence. BTMs cannot be used in individual patients for identifying accelerated bone loss or an increase in fracture risk or in deciding on the optimal therapy. They are useful for monitoring both anti-resorptive and anabolic treatment. Response can be defined as a result that exceeds an absolute target, or by a change greater than the least significant change; if such a response is not present, then poor compliance or secondary osteoporosis are likely causes. A baseline BTM measurement is not always made; in that case, a value of BTM on anti-resorptive treatment that is low or low normal or above the reference interval for anabolic therapy may be taken to indicate a satisfactory response. We provide an approach to using these bone turnover markers in clinical practice by describing algorithms for anti-resorptive and anabolic therapy and describing the changes we observe in the clinical practice setting.

Use of bone turnover markers in postmenopausal osteoporosis

Bone turnover comprises two processes: the removal of old bone (resorption) and the laying down of new bone (formation). N-terminal propeptide of type I procollagen (PINP) and C-telopeptide of type I collagen (CTX-I) are markers of bone formation and resorption, respectively, that are recommended for clinical use. Bone turnover markers can be measured on several occasions in one individual with good precision. However, these markers are subject to several sources of variability, including feeding (resorption decreases) and recent fracture (all markers increase for several months). Bone turnover markers are not used for diagnosis of osteoporosis and do not improve prediction of bone loss or fracture within an individual. In untreated women, very high bone turnover marker concentrations suggest secondary causes of high bone turnover (eg, bone metastases or multiple myeloma). In people with osteoporosis, bone turnover markers might be useful to assess the response to anabolic and antiresorptive therapies, to assess compliance to therapy, or to indicate possible secondary osteoporosis. Much remains to be learnt about how bone turnover markers can be used to monitor the effect of stopping bisphosphonate therapy (eg, to identify a threshold above which restarting therapy should be considered). More studies are needed to investigate the use of bone turnover markers for assessment of the bone safety of new medications.

The cumulative incidence of and risk factors for latent beaking in patients with autoimmune diseases taking long-term glucocorticoids and bisphosphonates

SUMMARY

The incidence of beaking, which has been reported to precede atypical femoral fracture, was high and increased over 2 years in patients with autoimmune diseases who were taking bisphosphonates and glucocorticoids. Regular femoral X-rays are strongly recommended to screen for beaking, and bisphosphonate drug holidays should be considered.

INTRODUCTION

Atypical femoral fractures (AFFs) have been recently recognized as complications associated with bisphosphonate (BP) use. AFFs are considered to be stress fractures; localized periosteal thickening of the lateral cortex is often present at the fracture site; this thickening is termed "beaking." Beaking has been reported to precede AFF. The aims of the present study were to evaluate the incidence of latent beaking in patients with autoimmune diseases taking BPs and glucocorticoids and to identify risk factors for beaking.

METHODS

A total of 125 patients with autoimmune diseases who were taking BPs and glucocorticoids was included; 116 patients underwent X-rays and analysis of serum and urine bone metabolic markers annually for 2 years. Mean patient age was 54.5 years; there were 105 (90.5%) females and the mean duration of disease was 13.2 years. Focal lateral cortical thickening in femoral X-rays was defined as beaking.

RESULTS

Beaking was detected in 15 femora of 10 patients (8.0%) at the time of recruitment. Over the 2-year observation period, the incidence of beaking increased to 21 femora of 12 patients (10.3%), and a complete AFF at the location of beaking occurred in one patient. Beaking was associated with a longer duration of BP treatment (6.1 ± 1.0 years vs. 5.0 ± 2.9 years, p = 0.01). Age 40-60 years, BP therapy ≥4 years, and diabetes mellitus were significantly associated with beaking.

CONCLUSIONS

The incidence of beaking was high, and increased over 2 years, in patients with autoimmune diseases who were taking BPs and glucocorticoids. Regular femoral X-rays are strongly recommended to screen for beaking. Long-term BP/glucocorticoid use was a risk factor for beaking in patients with autoimmune diseases; BP drug holidays should be considered.

Relationships between changes in bone mineral density or bone turnover markers and vertebral fracture incidence in patients treated with bazedoxifene

We analyzed the relationships between bone mineral density (BMD) or bone turnover marker (BTM) changes and vertebral fracture incidence in women treated with bazedoxifene using a post hoc analysis from a 3-year randomized, placebo-controlled study evaluating the effect of bazedoxifene (20 or 40 mg) on fracture risk reduction. BMD was assessed at baseline and every 6 months for 3 years. Osteocalcin and C-telopeptide of type I collagen were assessed at baseline and at 3, 12, and 36 months. Vertebral fractures were assessed with a semiquantitative visual assessment. Data were available for 5,244 women, of whom 3,476 were treated with bazedoxifene. Using a logistic regression analysis and the classical Li approach, the proportion of fracture incidence explained by BMD change after 3 years of bazedoxifene treatment was 29 % for the total hip and 44 % for the femoral neck. The proportion of treatment explained by lumbar BMD change could not be quantified accurately because of the significant interaction between treatment and change in BMD. With the same model, the 12-month BTM changes explained up to 29 % of the fracture risk reduction observed with the two forms of bazedoxifene. In women treated with bazedoxifene, changes in femoral neck BMD, hip BMD, or BTMs explained a moderate proportion of the fracture risk reduction observed during the 3 years of follow-up. However, BMD or BTM changes cannot be recommended for individual monitoring of women treated with bazedoxifene.