Goal-directed therapy in osteoporosis

Relationship Between Bone Mineral Density T-Score and Nonvertebral Fracture Risk Over 10 Years of Denosumab Treatment

Although treat-to-target strategies are being discussed in osteoporosis, there is little evidence of what the target should be to reduce fracture risk maximally. We investigated the relationship between total hip BMD T-score and the incidence of nonvertebral fracture in women who received up to 10 years of continued denosumab therapy in the FREEDOM (3 years) study and its long-term Extension (up to 7 years) study. We report the percentages of women who achieved a range of T-scores at the total hip or femoral neck over 10 years of denosumab treatment (1343 women completed 10 years of treatment). The incidence of nonvertebral fractures was lower with higher total hip T-score. This relationship plateaued at a T-score between -2.0 and -1.5 and was independent of age and prevalent vertebral fractures, similar to observations in treatment-naïve subjects. Reaching a specific T-score during denosumab treatment was dependent on the baseline T-score, with higher T-scores at baseline more likely to result in higher T-scores at each time point during the study. Our findings highlight the importance of follow-up BMD measurements in patients receiving denosumab therapy because BMD remains a robust indicator of fracture risk. These data support the notion of a specific T-score threshold as a practical target for therapy in osteoporosis. © 2019 The Authors Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).

Osteoporosis: Treat-to-Target

PURPOSE OF REVIEW

Treat-to-target (goal-directed therapy) has been proposed as a strategy to assist clinicians in selecting the most appropriate initial treatment for osteoporosis and guiding subsequent decisions to continue, change, or stop treatment. This is a review of the current medical evidence regarding treatment targets and potential clinical applications in managing patients with osteoporosis.

RECENT FINDINGS

Analyses of randomized placebo-controlled trials of approved agents to treat osteoporosis have generally shown that larger increases in bone mineral density are associated with greater reduction in fracture risk. Achievement of T-scores > -2.5 to -2.0 with treatment appears to provide little additional fracture protection. The paradigm of treat-to-target is aimed at enhancing and individualizing the care of patients with osteoporosis. Based on the best available data, the most promising target is T-score > -2.5. More data are needed to validate the clinical utility of treat-to-target for osteoporosis.

FRAX updates 2016

PURPOSE OF REVIEW

In the 8 years since the launch of the FRAX tool, it has continued to grow with the addition of new country or territory models. Although the core of the fracture risk algorithm remains unchanged, there is growing evidence of possible additional independent clinical variables that might modulate the interpretation of the FRAX outputs. There is also an expanding number of international guidelines that incorporate FRAX assessments, leading to discussions on the use of FRAX in treated patients and the determination of intervention thresholds.

RECENT FINDINGS

This review encompasses recent information on the use of FRAX in immigrant populations and the potential influence of skeletal and extraskeletal risk factors on FRAX estimations. For example, trabecular bone score and falls risk appear to be promising additional factors in individual risk assessment. FRAX appears to remain accurate in those on osteoporosis treatments, but FRAX is not a suitable tool for use in treat-to-target strategies.

SUMMARY

The assessment of fracture risk in immigrants is probably more accurate with the use of the FRAX tool for the country of origin, if available. The impact of additional risk variables will need evaluation of the impact of these on recharacterizing patients by moving them across intervention thresholds.

Italian association of clinical endocrinologists (AME) position statement: drug therapy of osteoporosis

Treatment of osteoporosis is aimed to prevent fragility fractures and to stabilize or increase bone mineral density. Several drugs with different efficacy and safety profiles are available. The long-term therapeutic strategy should be planned, and the initial treatment should be selected according to the individual site-specific fracture risk and the need to give the maximal protection when the fracture risk is highest (i.e. in the late life). The present consensus focused on the strategies for the treatment of postmenopausal osteoporosis taking into consideration all the drugs available for this purpose. A short revision of the literature about treatment of secondary osteoporosis due both to androgen deprivation therapy for prostate cancer and to aromatase inhibitors for breast cancer was also performed. Also premenopausal females and males with osteoporosis are frequently seen in endocrine settings. Finally particular attention was paid to the tailoring of treatment as well as to its duration.

Proportion of osteoporotic women remaining at risk for fracture despite adherence to oral bisphosphonates

BACKGROUND

Adherence to oral bisphosphonates is often low, but even adherent patients may remain at elevated fracture risk. The goal of this study was to estimate the proportion of bisphosphonate-adherent women remaining at high risk of fracture.

METHODS

A retrospective cohort of women aged 50years and older, adherent to oral bisphosphonates for at least two years was identified, and data were extracted from a multi-system health information exchange. Adherence was defined as having a dispensed medication possession ratio≥0.8. The primary outcome was clinical occurrence of: low trauma fracture (months 7-36), persistent T-score≤-2.5 (months 13-36), decrease in bone mineral density (BMD) at any skeletal site≥5%, or the composite of any one of these outcomes.

RESULTS

Of 7435 adherent women, 3110 had either pre- or post-adherent DXA data. In the full cohort, 7% had an incident osteoporotic fracture. In 601 women having both pre- and post-adherent DXA to evaluate BMD change, 6% had fractures, 22% had a post-treatment T-score≤-2.5, and 16% had BMD decrease by ≥5%. The composite outcomes occurred in 35%. Incident fracture was predicted by age, previous fracture, and a variety of co-morbidities, but not by race, glucocorticoid treatment or type of bisphosphonate.

CONCLUSION

Despite bisphosphonate adherence, 7% had incident osteoporotic fractures and 35% had either fracture, decreases in BMD, or persistent osteoporotic BMD, representing a substantial proportion of treated patients in clinical practices remaining at risk for future fractures. Further studies are required to determine the best achievable goals for osteoporosis therapy, and which patients would benefit from alternate therapies.

Fracture prediction from repeat BMD measurements in clinical practice

We investigated whether repeat BMD measurements in clinical populations are useful for fracture risk assessment. We report that repeat BMD measurements are a robust predictor of fracture in clinical populations; this is not affected by preceding BMD change or recent osteoporosis therapy.

INTRODUCTION

In clinical practice, many patients selectively undergo repeat bone mineral density (BMD) measurements. We investigated whether repeat BMD measurements in clinical populations are useful for fracture risk assessment and whether this is affected by preceding change in BMD or recent osteoporosis therapy.

METHODS

We identified women and men aged ≥ 50 years who had a BMD measurement during 1990-2009 from a large clinical BMD database for Manitoba, Canada (n = 50,215). Patient subgroups aged ≥ 50 years at baseline with repeat BMD measures were identified. Data were linked to an administrative data repository, from which osteoporosis therapy, fracture outcomes, and covariates were extracted. Using Cox proportional hazards models, we assessed covariate-adjusted risk for major osteoporotic fracture (MOF) and hip fracture according to BMD (total hip, lumbar spine, femoral neck) at different time points.

RESULTS

Prevalence of osteoporosis therapy increased from 18 % at baseline to 55 % by the fourth measurement. Total hip BMD was predictive of MOF at each time point. In the patient subgroup with two repeat BMD measurements (n = 13,481), MOF prediction with the first and second measurements was similar: adjusted-hazard ratio (HR) per SD 1.45 (95 % CI 1.34-1.56) vs. 1.64 (95 % CI 1.48-1.81), respectively. No differences were seen when the second measurement results were stratified by preceding change in BMD or osteoporosis therapy (both p-interactions >0.2). Similar results were seen for hip fracture prediction and when spine and femoral neck BMD were analyzed.

CONCLUSION

Repeat BMD measurements are a robust predictor of fracture in clinical populations; this is not affected by preceding BMD change or recent osteoporosis therapy.

Goal-directed treatment of osteoporosis in Europe

Despite the proven predictive ability of bone mineral density, Fracture Risk Assessment Tool (FRAX®), bone turnover markers, and fracture for osteoporotic fracture, their use as targets for treatment of osteoporosis is limited.

INTRODUCTION

Treat-to-target is a strategy applied in several fields of medicine and has recently become an area of interest in the management of osteoporosis. Its role in this setting remains controversial. This article was prepared following a European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) working group meeting convened under the auspices of the International Osteoporosis Foundation (IOF) to discuss the feasibility of applying such a strategy in osteoporosis in Europe.

METHODS

Potential targets range from the absence of an incident fracture to fixed levels of bone mineral density (BMD), a desired FRAX® score, a specified level of bone turnover markers or indeed changes in any one or a combination of these parameters.

RESULTS

Despite the proven predictive ability of all of these variables for fracture (particularly BMD and FRAX), their use as targets remains limited due to low sensitivity, the influence of confounders and current lack of evidence that targets can be consistently reached.

CONCLUSION

ESCEO considers that it is not currently feasible to apply a treat-to-target strategy in osteoporosis, though it did identify a need to continue to improve the targeting of treatment to those at higher risk (target-to-treat strategy) and a number of issues for the research agenda. These include international consensus on intervention thresholds and definition of treatment failure, further exploration of the relationship between fracture and BMD, and FRAX and treatment efficacy and investigation of the potential of short-term targets to improve adherence.

Can change in FRAX score be used to "treat to target"? A population‐based cohort study

It is unknown how responsive the Fracture Risk Assessment (FRAX) tool is to osteoporosis treatment (OTX) or whether it can serve as a target for "goal‐directed" treatment. We studied 11,049 untreated women aged ≥50 years undergoing baseline and follow‐up DXA examinations in Manitoba, Canada. We identified clinical risk factors, intervening OTX based on medication possession ratios (MPR),and incident fractures. FRAX scores for major osteoporotic and hip fractures were computed for each scan using the most current(updated) FRAX inputs. Over 4 years, median FRAX scores showed an increase of 1.1% for major fractures and 0.3% for hip fractures,including women highly adherent to OTX (0.6% and 0.1% increases). Few (2.2%) highly adherent women had a decrease in major fracture probability exceeding 4%, whereas 9.0% had a decrease in hip fracture probability exceeding 1%. Compared with untreated women, OTX was associated with a higher dose‐dependent likelihood of attenuating the expected increase in major fracture risk:adjusted odds ratios (aOR) 2.3 (95% confidence interval [CI] 1.8–2.9) for MPR <0.50; 7.3 (95% CI 5.6–9.6) for MPR 0.50–0.79; and 12.0(95% CI 9.5–15.2) for MPR ≥0.80. In the 4 years after the second DXA scan, 620 (6%) women had major fractures (152 hip fractures). FRAX scores were strongly predictive of incident major fractures (adjusted hazard ratios [aHR] per SD increase in FRAX 1.8, 95%CI 1.7–1.9) and hip fractures (aHR per SD 4.5, 95% CI 3.7–5.7); however, change in FRAX score was not independently associated with major fracture (p=0.8) or hip fracture (p=0.3). In conclusion, FRAX scores slowly increased over time, and this increase was attenuated but not prevented by treatment. Few women had meaningful reductions in FRAX scores, and change in FRAX score did not independently predict incident fracture, suggesting that FRAX with BMD is not responsive enough to be used as a target for goal‐directed treatment.