Effects of a 'drug holiday' on bone mineral density and bone turnover marker during bisphosphonate therapy

Real-world bone turnover marker use: impact on treatment decisions and fracture

The use of bone turnover marker (BTM) testing for patients with osteoporosis in the USA has not been well characterized. This retrospective US-based real-world data study found BTM testing has some association with treatment decision-making and lower fracture risk in patients with presumed osteoporosis, supporting its use in clinical practice.

INTRODUCTION

The purpose of this study was to characterize bone turnover marker (BTM) testing patterns and estimate their clinical utility in treatment decision-making and fragility fracture risk in patients with osteoporosis using a retrospective claims database.

METHODS

Data from patients aged ≥ 50 years with newly diagnosed osteoporosis enrolled in the Truven MarketScan^® Commercial Claims and Encounters and Medicare Supplemental and Co-ordination of Benefits databases from January 2008 to June 2018 were included. Osteoporosis was ascertained by explicit claims, fragility fracture events associated with osteoporosis, or prescribed anti-resorptive or anabolic therapy. BTM-tested patients were 1:1 propensity score matched to those untested following diagnosis. Generalized estimating equation models were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for testing versus no testing on both treatment decision-making and fragility fracture.

RESULTS

Of the 457,829 patients with osteoporosis, 6075 were identified with ≥ 1 BTM test following diagnosis; of these patients, 1345 had a unique treatment decision made ≤ 30 days from BTM testing. The percentage of patients receiving BTM tests increased significantly each year (average annual % change: + 8.1%; 95% CI: 5.6-9.0; p = 0.01). Patients tested were significantly more likely to have a treatment decision (OR: 1.14; 95% CI: 1.13-1.15), and testing was associated with lower odds of fracture versus those untested (OR: 0.87; 95% CI: 0.85-0.88).

CONCLUSION

In this large, heterogeneous population of patients with presumed osteoporosis, BTM testing was associated with treatment decision-making, likely leading to fragility fracture reduction following use.

Pharmacology of bisphosphonates

The biological effects of the bisphosphonates (BPs) as inhibitors of calcification and bone resorption were first described in the late 1960s. In the 50 years that have elapsed since then, the BPs have become the leading drugs for the treatment of skeletal disorders characterized by increased bone resorption, including Paget's disease of bone, bone metastases, multiple myeloma, osteoporosis and several childhood inherited disorders. The discovery and development of the BPs as a major class of drugs for the treatment of bone diseases is a paradigm for the successful journey from "bench to bedside and back again". Several of the leading BPs achieved "blockbuster" status as branded drugs. However, these BPs have now come to the end of their patent life, making them highly affordable. The opportunity for new clinical applications for BPs also exists in other areas of medicine such as ageing, cardiovascular disease and radiation protection. Their use as inexpensive generic medicines is therefore likely to continue for many years to come. Fifty years of research into the pharmacology of bisphosphonates have led to a fairly good understanding about how these drugs work and how they can be used safely in patients with metabolic bone diseases. However, while we seemingly know much about these drugs, a number of key aspects related to BP distribution and action remain incompletely understood. This review summarizes the existing knowledge of the (pre)clinical and translational pharmacology of BPs, and highlights areas in which understanding is lacking.

Determinants of change in bone mineral density and fracture risk during bisphosphonate holiday

In a retrospective analysis of 208 osteoporotic patients followed during a bisphosphonate holiday, lower body weight and risedronate use were associated with a more rapid decline in bone mineral density during the bisphosphonate holiday, while bone mineral density (BMD) trends were similar in patients who sustained vs. did not sustain a fracture.

INTRODUCTION

A drug holiday has been suggested for some bisphosphonate-treated patients with osteoporosis to minimize potential side effects from prolonged use. However, there is limited information on the evolution of BMD during a bisphosphonate holiday. Our study analyzed the longitudinal course of BMD following bisphosphonate discontinuation and assessed its determinants.

METHODS

Retrospective single-center cohort study of osteoporosis patients treated with alendronate or risedronate for at least 2 years and then discontinued their bisphosphonate for a drug holiday. Patients were stratified by bisphosphonate type and by fracture occurrence during drug holiday.

RESULTS

A total of 208 patients were included in this analysis (87.5 % female). At the time of bisphosphonate cessation, mean ± SD age was 66.9 ± 8.9 years and BMI 24.5 ± 4.4 kg/m(2). Duration of bisphosphonate treatment was 5.2 ± 2.3 years, and follow-up during holiday was 3.3 ± 1.7 years. During the first 2 years of the holiday, BMD remained stable at the lumbar spine and femoral neck, but declined significantly at the total hip. BMD declined significantly at all sites thereafter. Significant predictors of BMD decline during bisphosphonate holiday included lower BMI at the start of the holiday and change in body weight during the holiday. BMD decline was more pronounced in former risedronate compared to former alendronate users. BMD trends were similar in patients who sustained vs. did not sustain a fracture during the holiday.

CONCLUSIONS

BMD at the total hip declines significantly within 1 year of bisphosphonate discontinuation, particularly in lean patients. Additional studies are needed to identify predictors of fracture incidence during a bisphosphonate holiday.

Serum Markers of Bone Turnover and Angiogenesis in Patients With Bisphosphonate-Related Osteonecrosis of the Jaw After Discontinuation of Long-Term Intravenous Bisphosphonate Therapy

PURPOSE

To analyze serum markers of bone turnover, angiogenesis, endocrine function, and inflammation in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) who discontinued long-term intravenous bisphosphonate (BP) therapy.

PATIENTS AND METHODS

Serum samples were obtained from 25 BRONJ patients who had discontinued long-term intravenous BP therapy for an average of 11.4 ± 8.7 months and 48 non-BRONJ controls who continued receiving intravenous BP therapy. Samples were analyzed for total alkaline phosphatase, bone-specific alkaline phosphatase, osteocalcin, C-telopeptide, vascular endothelial growth factor, triiodothyronine, thyroxine, thyroid-stimulating hormone, 25-hydroxyvitamin D, and C-reactive protein.

RESULTS

The mean number of BP infusions was significantly higher in BRONJ patients compared with controls (38.4 ± 26.3 infusions vs 18.8 ± 7.2 infusions, P < .0001); however, the duration of BP therapy was not significantly different between the groups (P = .23). Overall, there were no significant differences in any of the markers between BRONJ patients and controls (all P values ≥ .16). In a subgroup analysis that matched BRONJ patients and controls according to mean age and number of BP infusions (10 BRONJ patients and 48 controls), log10 vascular endothelial growth factor (2.9 ± 0.4 pg/mL vs 2.4 ± 0.4 pg/mL, P < .001) and C-reactive protein (34 ± 26 mg/L vs 13 ± 8 mg/L, P < .01) levels were significantly higher in BRONJ patients compared with controls. Within BRONJ patients, none of the serum markers were correlated with duration of BP discontinuation.

CONCLUSIONS

Levels of bone turnover and endocrine markers in BRONJ patients who discontinue long-term intravenous BP therapy are similar to those in non-BRONJ controls receiving intravenous BP therapy. However, levels of angiogenesis and inflammation markers are higher in BRONJ patients who discontinue long-term intravenous BP therapy. The prolonged skeletal half-life of BPs may suppress bone turnover markers in BRONJ patients for several years after discontinuation of intravenous BP therapy, suggesting an extended effect on bone homeostasis.

Analysis of osteoporosis treatment patterns with bisphosphonates and outcomes among postmenopausal veterans

PURPOSE

Adherence and persistence with bisphosphonates are frequently poor, and stopping, restarting, or switching bisphosphonates is common. We evaluated bisphosphonate change behaviors (switching, discontinuing, or reinitiating) over time, as well as fractures and costs, among a large, national cohort of postmenopausal veterans.

METHODS

Female veterans aged 50+ treated with bisphosphonates during 2003-2011 were identified in Veterans Health Administration (VHA) datasets. Bisphosphonate change behaviors were characterized using pharmacy refill records. Patients' baseline disease severity was characterized based on age, T-score, and prior fracture. Cox Proportional Hazard analysis was used to evaluate characteristics associated with discontinuation and the relationship between change behaviors and fracture outcomes. Generalized estimating equations were used to evaluate the relationship between change behaviors and cost outcomes.

RESULTS

A total of 35,650 patients met eligibility criteria. Over 6800 patients (19.1%) were non-switchers. The remaining patients were in the change cohort; at least half displayed more than one change behavior over time. A strong, significant predictor of discontinuation was ≥5 healthcare visits in the prior year (11-23% more likely to discontinue), and discontinuation risk decreased with increasing age. No change behaviors were associated with increased fracture risk. Total costs were significantly higher in patients with change behaviors (4.7-19.7% higher). Change-behavior patients mostly had significantly lower osteoporosis-related costs than non-switchers (22%-118% lower).

CONCLUSIONS

Most bisphosphonate patients discontinue treatment at some point, which did not significantly increase the risk of fracture in this majority non-high risk population. Bisphosphonate change behaviors were associated with significantly lower osteoporosis costs, but significantly higher total costs.

Oral Bisphosphonate and Risk of Esophageal Cancer: A Nationwide Claim Study

Background

Epidemiology studies suggest that oral bisphosphonate may increase the risk of esophageal cancer. The present study aimed to investigate the association between exposure of oral bisphosphonate and risk of esophageal cancer.

Methods

Using the nationwide medical claim database in South Korea, 2,167,955 subjects, who initiated osteoporosis treatment (oral bisphosphonate, intravenous bisphosphonate or raloxifene) or performed dual energy X-ray absorptiometry (DXA) between 2008 and 2012, were analyzed. Diagnosis of esophageal cancer was estimated from medical claim database. Standardized incidence ratio (SIR) was estimated by comparing with incidence in the general population. Cox proportional hazards modeling was used to investigate age-adjusted hazard ratio (aHR) of esophageal cancer.

Results

The present study included oral bisphosphonate group (N=1,435,846), comparator group 1 (intravenous bisphosphonate or raloxifene, N=78,363) and comparator group 2 (DXA, N=653,746). Mean age was 65.6±8.8 years and mean observation duration was 30.9±17.7 months. During 5,503,688 patient-years, 205 esophageal cancer incidences were observed. The annual incidence of esophageal cancer was 3.88, 4.21, and 3.30 for oral bisphosphonate group, comparator group 1 and comparator group 2, respectively. SIR of esophageal cancer was 1.24, 1.38, and 1.40 for oral bisphosphonate group, comparator group 1 and comparator group 2, respectively. Esophageal cancer risk of oral bisphosphonate group was not significantly different from comparator group 1 and comparator group 2 (aHR 0.87; 95% confidence interval [CI] 0.39-1.98 and aHR 0.94; 95% CI 0.68-1.30, respectively).

Conclusions

The use of oral bisphosphonate was not associated with increased risk of esophageal cancer in real clinical practice using large scale nationwide database.