Exploring methods for comparing the real-world effectiveness of treatments for osteoporosis: adjusted direct comparisons versus using patients as their own control

Risk of first hip fracture under treatment with zoledronic acid versus alendronate: a NOREPOS cohort study of 88,000 Norwegian men and women in outpatient care

We aimed to investigate the risk of hip fracture associated with zoledronic acid treatment compared to alendronate on a population level. The risk of hip fracture was lower in women using zoledronic acid and higher in women who had discontinued treatment. The findings support the effectiveness of intravenous bisphosphonate.

PURPOSE

To investigate whether zoledronic acid (ZOL) was associated with a lower risk of the first hip fracture than alendronate (ALN) in Norway using real-world data.

METHODS

Nationwide data on drugs dispensed in outpatient pharmacies were individually linked with all hospital-treated hip fractures. Individuals aged 50-89 years without previous hip fracture were included at their first filling of a prescription for ALN or ZOL during 2005-2016. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) for first hip fracture by time-varying exposure to ZOL versus ALN were estimated in sex-stratified flexible parametric survival analyses. Covariates included time-varying accumulated ALN exposure and comorbidity level expressed by the prescription-based Rx-Risk Comorbidity Index, marital status, education, and residential urbanity.

RESULTS

Of 75,250 women who initiated treatment, 72,614 (96.5%) were exposed to ALN and 6366 (8.5%) to ZOL. Of 12,739 men who initiated treatment, 12,311 (96.6%) were exposed to ALN and 784 (6.2%) to ZOL. In women, the HR for first hip fracture was 0.75 (95% CI: 0.61-0.91) for ZOL versus ALN. In men, the corresponding HR was 0.59 (95% CI: 0.32-1.07). Discontinued treatment was associated with increased risk compared with current ALN treatment in women (HR: 1.33; 95% CI: 1.24-1.42, men: HR 1.13 (95% CI: 0.95-1.35)).

CONCLUSIONS

In women, the risk of first hip fracture when treated with ZOL was 25% lower than when treated with ALN. Discontinued treatment was associated with a 33% increase in hip fracture risk. Similar, albeit statistically non-significant, results were observed in men.

Intermittent dosing of zoledronic acid based on bone turnover marker assessment reduces vertebral and non-vertebral fractures

Previous studies have demonstrated that the administration of zoledronic acid (ZOL) once yearly for 3 years or once over 3 years, yields similar antifracture efficacy. Bone turnover markers can predict the antifracture efficacy of antiresorptive agents, with procollagen type 1 N-terminal propeptide (P1NP) being the most useful marker. In this retrospective cohort study, we explored the effects of intravenous dosing of ZOL guided by serum (S)-P1NP assessment on bone mineral density (BMD) and fractures. Consenting patients (N = 202, mean age 68.2 years) with osteoporosis were treated with ZOL for an average of 4.4 (range 2-8) years. S-P1NP and BMD were measured at baseline and every 1-2 years. We assessed the number of subsequent vertebral and nonvertebral fractures in the 2-year time periods. The number of patients assessed was 202, 147, 69, and 29 at years 1-2, 3-4, 5-6, and 7-8, respectively. A new ZOL infusion was given if S-P1NP exhibited values above 35 μg/L. BMD increased by 6.2% (SD 4.0) over the first 2 years and stabilized in years 2-8 (P <.05). Median S-P1NP exhibited an initial reduction from 58.0 to 31.3 μg/L at year 2 and then increased to 39.0 μg/L at years 7-8. Compared with fractures observed in the last 2 years before baseline, fracture rates exhibited consistent reductions, for vertebral fractures odds ratio (OR) [95% confidence interval] = 0.61 [0.47, 0.80], P <.001 and for nonvertebral fractures OR = 0.23 [0.18, 0.31], P <.001. In conclusion, intermittent dosing of intravenous ZOL based on the assessment of S-P1NP with cut-off at 35 μg/L resulted in an initial increase followed by a stable BMD, suppression of S-P1NP, and stable reduction of fractures for 8 years. Only 39% of patients needed more than one infusion. This approach reduces healthcare costs and might also reduce the risk of rare side effects such as osteonecrosis of the jaw and atypical femoral fracture.

Real-World Effectiveness of Osteoporosis Medications in France: A Nationwide Cohort Study

Although drugs for osteoporosis have been demonstrated to be effective in reducing fracture risk in placebo-controlled clinical trials, data on effectiveness in real-world practice is limited. Data from the French national health insurance claims database (SNDS) were used to follow five cohorts of women aged ≥55 years after initiating treatment for ≥6 months with either denosumab, zoledronic acid, oral bisphosphonates, raloxifene, or teriparatide in 2014-2016. Fracture incidence was compared within each cohort between the 3 months following initiation (baseline fracture risk) and the 12month, 18month, and 24 month postinitiation periods. Data are presented as incidence rate ratios (IRRs) with their 95% confidence intervals (CIs)s. Overall, 67,046 women were included in the denosumab cohort, 52,914 in the oral bisphosphonate cohort, 41,700 in the zoledronic acid cohort, 11,600 in the raloxifene cohort, and 7510 in the teriparatide cohort. The baseline vertebral fracture rate ranged from 1.74 per 1000 person years (‰PY) in the raloxifene cohort to 34.75‰PY in the teriparatide cohort, and the baseline hip fracture rate from 0.70‰PY in the raloxifene cohort to 10.52‰PY in the zoledronic acid cohort. Compared with the baseline fracture rate, vertebral fractures involving hospitalization were significantly reduced in the 3-24-month postinitiation period with denosumab (IRR 0.6; 95% CI, 0.5-0.7), zoledronic acid (IRR 0.4; 95% CI, 0.3-0.4), teriparatide (IRR 0.3; 95% CI, 0.2-0.5), and oral bisphosphonates (IRR 0.6; 95% CI, 0.4-0.8). Hip fracture incidence was reduced with denosumab (IRR 0.8; 95% CI, 0.6-0.9), but higher for oral bisphosphonates (IRR 1.7; 95% CI, 1.2-2.3); no significant change in hip fracture rate was observed for zoledronic acid, teriparatide, or raloxifene. A reduction in nonvertebral, non-hip fracture incidence was observed only in the denosumab cohort (IRR 0.8; 95% CI, 0.7-0.9). These findings indicate that treatment with osteoporosis drugs is effective in the real-world setting. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Real-world effectiveness of osteoporosis treatments in Germany

This observational study assessed the impact on the fracture incidence of osteoporosis medications in postmenopausal women in Germany. Continued treatment with osteoporosis medications was associated with reductions of fracture rates in a real-world setting.

PURPOSE

The efficacy of osteoporosis medications has been demonstrated in clinical trials, but a lack of evidence exists of their real-world effectiveness. This real-world study assessed the treatment patterns and impact on the fracture incidence of osteoporosis medications in postmenopausal women in Germany.

METHODS

This cohort study used data from the WIG2 benchmark database, a German anonymised healthcare claims database. All women ≥ 50 years of age with ≥ 1 prescription for osteoporosis medication between 1 January 2013 and 31 December 2017 were included. The primary outcome was treatment effectiveness, evaluated as the change in fracture incidence after initiating treatment. Fracture types included all fractures, clinical vertebral, hip and wrist/forearm. Fracture incidence was assessed during the early-treatment period (0-3 months) and the on-treatment period (4-12, 13-24, 25-36 and 37-48 months).

RESULTS

Baseline covariates and treatment patterns were determined for 41,861 patients. The median duration of therapy was longer with denosumab (587 days) than with intravenous ibandronate (451 days), intravenous zoledronate (389 days) or oral bisphosphonates (258 days). The baseline incidence rate of all fractures was higher in patients receiving denosumab than in those receiving other treatments (87.6, 78.2, 56.6 and 66.0 per 1000 person-years for denosumab, oral bisphosphonates, intravenous ibandronate and intravenous zoledronate, respectively). Rates of all fractures declined with continued denosumab (by 38%, 50%, 56% and 67% at 12, 24, 36 and 48 months, respectively) and oral bisphosphonates (by 39%, 44%, 49% and 42%, respectively) treatment.

CONCLUSION

Continued treatment with osteoporosis medications was associated with reductions of fracture rates in a real-world setting.

Real-world effectiveness of osteoporosis treatment in the oldest old

We studied effectiveness of osteoporosis treatment in women older than 80 years, who often are not included in clinical trials. Treatments were as effective on bone density and fractures as in younger women.

INTRODUCTION

To study real-world effectiveness of osteoporosis treatment on BMD and fractures in the oldest old women (≥ 80 years) compared with women (60-79 years) in the clinical setting using Swedish health register data.

METHODS

National registers and data from DXA machines were used to study effectiveness of all available osteoporosis treatments in women 60-79 and ≥ 80 years using three approaches: (1) Total Hip BMD change up to 8 years after treatment start; (2) fracture incidence where patients served as their own controls, comparing the first 3 months after treatment start with the subsequent 12 months; and (3) comparison of fracture incidence post-fracture in women ≥ 80 years treated with osteoporosis treatment or calcium/vitamin D.

RESULTS

Analysis 1: Total Hip BMD increased by up to 6.7% and 7.7% in women 60-79 and ≥ 80 years old, respectively. The mean increase in BMD was 1.1%-units per year in both age groups. Analysis 2: Relative to the 3-month baseline, fracture incidence decreased during the subsequent 12 months of treatment. Incidence rate ratios were estimated at 0.65, 0.74, 0.29, and 0.81 for any, hip, vertebral, and non-hip-non-vertebral fracture, respectively. Analysis 3: A 24-month incidence of any fracture in women ≥ 80 years given post-fracture osteoporosis treatment was lower (HR = 0.78) than in women given calcium/vitamin D, but treatment allocation was not random, with lower mortality (HR = 0.51) in patients receiving OP treatment.

CONCLUSIONS

Osteoporosis medication in women > 80 years in clinical practice likely works, and the magnitude of effect is similar to what was estimated in younger women. The choice between osteoporosis treatment and calcium/vitamin D after fracture in women ≥ 80 years is not random but appears associated with the patient's health status and presence of vertebral fractures, rather than the known risk profile of sustaining a fracture at a high age.

Using negative control outcomes to assess the comparability of treatment groups among women with osteoporosis in the United States

PURPOSE

In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications.

METHODS

Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights.

RESULTS

Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = -0.6%, 95% CI: -1.1, -0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations.

CONCLUSIONS

Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies.