Incidence of fractures of the femur, including subtrochanteric, up to 8 years since initiation of oral bisphosphonate therapy: a register-based cohort study using the US MarketScan claims databases

Antiresorptive Drugs and the Risk of Femoral Shaft Fracture in Men and Women With Osteoporosis: A Cohort Study Using the National Database of Health Insurance Claims of Japan

BACKGROUND

This cohort study aimed to estimate incidence rates of femoral shaft fracture in patients who were treated with antiresorptive drugs.

METHODS

We used data from the National Database of Health Insurance Claims of Japan from April 2009 and October 2016. All patients with new use of an antiresorptive drug, prescription-free period of ≥3 months, and no prior femoral fractures were included. Femoral shaft fractures were identified using a validated definition based on International Classification of Diseases, 10th revision (ICD-10) codes. Incidence rate ratios were estimated using Poisson regression, with adjustment for sex, age, and the Charlson Comorbidity Index.

RESULTS

We identified 7,958,655 patients (women: 88.4%; age ≥75 years: 51.2%). Femoral shaft fractures were identified in 22,604 patients. Incidence rates per 100,000 person-years were 74.8 for women, 30.1 for men, 30.1 for patients aged ≤64 years, 47.7 for patients aged 65-74 years, and 99.0 for patients aged ≥75 years. Adjusted incidence rate ratios in patients taking versus not taking each type of antiresorptive drug were 1.00 (95% confidence interval [CI], 0.98-1.03) for bisphosphonates, 0.46 (95% CI, 0.44-0.48) for selective estrogen receptor modulators, 0.24 (95% CI, 0.18-0.32) for estrogens, 0.75 (95% CI, 0.71-0.79) for calcitonins, and 0.93 (95% CI, 0.84-1.03) for denosumab. The adjusted incidence rate ratio for alendronate was 1.18 (95% CI, 1.14-1.22).

CONCLUSION

The incidence rates of femoral shaft fracture varied across patients treated with different antiresorptive drugs. Further research on a specific antiresorptive drug can increase understanding of the risk of femoral shaft fracture.

Economic burden of acute otitis media, pneumonia, and invasive pneumococcal disease in children in the United States after the introduction of 13-valent pneumococcal conjugate vaccines during 2014-2018

BACKGROUND

Streptococcus pneumoniae remains a leading cause of morbidity, mortality, and healthcare resource utilization (HRU) among children. This study quantified HRU and cost of acute otitis media (AOM), pneumonia, and invasive pneumococcal disease (IPD).

METHODS

The IBM MarketScan® Commercial Claims and Encounters and Multi-State Medicaid databases from 2014 to 2018 were analyzed. Children with AOM, all-cause pneumonia, or IPD episodes were identified using diagnosis codes in inpatient and outpatient claims. HRU and costs were described for each condition in the commercial and Medicaid-insured populations. National estimates of the number of episodes and total cost ($US 2019 for each condition were extrapolated using data from the US Census Bureau.

RESULTS

Approximately 6.2 and 5.6 million AOM episodes were identified in commercial and Medicaid-insured children, respectively, during the study period. Mean cost per AOM episode was $329 (SD $1505) for commercial and $184 (SD $1524) for Medicaid-insured children. A total of 619,876 and 531,095 all-cause pneumonia cases were identified among commercial and Medicaid-insured children, respectively. Mean cost per all-cause pneumonia episode was $2304 (SD $32,309) in the commercial and $1682 (SD $19,282) in the Medicaid-insured population. A total of 858 and 1130 IPD episodes were identified among commercial and Medicaid-insured children, respectively. Mean cost per IPD episode was $53,213 (SD $159,904) for commercial and $23,482 (SD $86,209) for the Medicaid-insured population. Nationally, there were over 15.8 million cases of AOM annually, with total estimated cost of $4.3 billion, over 1.5 million cases of pneumonia annually, with total cost of $3.6 billion, and about 2200 IPD episodes annually, for a cost of $98 million.

CONCLUSIONS

The economic burden of AOM, pneumonia, and IPD among US children remains substantial. IPD and its manifestations were associated with higher HRU and costs per episode, compared to AOM and all-cause pneumonia. However, owing to their higher frequencies, AOM and all-cause pneumonia were the main contributors to the economic burden of pneumococcal disease nationally. Additional interventions, such as the development of pneumococcal conjugate vaccinees with sustained protection of existing vaccine type serotypes as well as broader inclusion of additional serotypes, are necessary to further reduce the burden of disease caused by these manifestations.

Meta-analysis for the efficacy of bisphosphonates on hip fracture prevention

The aim of this study was to investigate the effect of bisphosphonates on preventing osteoporotic hip fracture in patients with or without prior major osteoporotic fracture. Randomized controlled trials (RCTs) and observational studies (OSs) based on electronic health records were used to assess bisphosphonate efficacy and were searched using PubMed, Scopus, and the Cochrane Library databases. Eight RCT studies and 14 OSs were extracted from the studies and quantitatively combined by random-effects meta-analysis. The odds ratio (OR) for all hip fractures in RCTs of 0.66, with a 95% confidence interval (CI) of 0.55-0.79, was lower than that in the OSs (OR 0.83; CI 0.74-0.94). The OR in patients with prior fracture was significantly reduced by bisphosphonates in both RCTs and OSs. Conversely, significant fracture reduction was not apparent in patients without prior fracture. A moderate relationship between prior major fracture rates and OR in hip fractures was defined. In patients with an average age of over 80 years, similar results were confirmed. In this meta-analysis, the efficacy of bisphosphonates was significant in patients with prior major fracture, recommending to prescribe for such patients. Their effect in patients without prior fracture, in contrast, remains unclear.

Treatment Discontinuation and Clinical Events in Type 2 Diabetes Patients Treated with Dipeptidyl Peptidase-4 Inhibitors or NPH Insulin as Third-Line Therapy

OBJECTIVE

To compare dipeptidyl peptidase-4 (DPP-4) inhibitors with neutral protamine Hagedorn (NPH) insulin, in terms of effectiveness and safety for the management of patients with type 2 diabetes mellitus (DM2) not controlled on metformin and sulfonylureas.

METHODS

A retrospective cohort study of individuals with DM2 newly dispensed with either DPP-4 inhibitors or NPH as third-line therapy, after metformin and sulfonylurea. Treatment discontinuation, macrovascular outcomes, and hypoglycemia were compared using multivariable Cox regression models, adjusted for sex, age, year of cohort entry, place of residence, hypertension, past history of hypoglycemia, diabetic ketoacidosis, comorbidities, and number of visits to emergency departments, outpatient physician, and hospitalizations.

RESULTS

Treatment discontinuation and hypoglycemia occurred more frequently with NPH than with DPP-4 inhibitor users. In the adjusted Cox model, the use of NPH compared to that of DPP-4 inhibitors was associated with a higher risk of discontinuation (HR: 1.33; 95% CI 1.27-1.40) and hypoglycemia (HR: 2.98; 95% CI 2.72-3.28). Risk of cardiovascular events was similar across groups.

CONCLUSIONS

This real-world analysis suggests that DM2 patients initiating third-line therapy with NPH have poorer control of diabetes when compared to DPP-4 inhibitor initiators.

Competing risks modeling of cumulative effects of time-varying drug exposures

An accurate assessment of drug safety or effectiveness in pharmaco-epidemiology requires defining an etiologically correct time-varying exposure model, which specifies how previous drug use affects the hazard of the event of interest. An additional challenge is to account for the multitude of mutually exclusive events that may be associated with the use of a given drug. To simultaneously address both challenges, we develop, and validate in simulations, a new approach that combines flexible modeling of the cumulative effects of time-varying exposures with competing risks methodology to separate the effects of the same drug exposure on different outcomes. To account for the dosage, duration and timing of past exposures, we rely on a spline-based weighted cumulative exposure modeling. We also propose likelihood ratio tests to test if the cumulative effects of past exposure on the hazards of the competing events are the same or different. Simulation results indicate that the estimated event-specific weight functions are reasonably accurate, and that the proposed tests have acceptable type I error rate and power. In real-life application, the proposed method indicated that recent use of antihypertensive drugs may reduce the risk of stroke but has no effect on the hazard of coronary heart disease events.

Long-Term Oral Bisphosphonate Therapy and Fractures in Older Women: The Women's Health Initiative

OBJECTIVES

To examine the association between long-term bisphosphonate use and fracture in older women at high risk of fracture.

DESIGN

Retrospective cohort.

SETTING

Women's Health Initiative.

PARTICIPANTS

Older women who reported at least 2 years of bisphosphonate use in 2008-09 (N = 5,120).

MEASUREMENTS

Exposure data were from a current medications inventory. Outcomes (hip, clinical vertebral, wrist or forearm, any clinical fracture) were ascertained annually. Using multivariate Cox proportional hazards models, the association between duration of bisphosphonate use (3-5, 6-9, 10-13 years) and fracture was estimated, using 2 years as the referent group.

RESULTS

On average participants were 80 years old and were followed for 3.7 ± 1.2 years. There were 127 hip, 159 wrist or forearm, 235 clinical vertebral, and 1,313 clinical fractures. In multivariate-adjusted analysis, 10 to 13 years of bisphosphonate use was associated with higher risk of any clinical fracture than 2 years of use (hazard ratio (HR) = 1.29, 95% confidence interval (CI) = 1.07-1.57). This association persisted in analyses limited to women with a prior fracture (HR = 1.30, 95% CI = 1.01-1.67) and women with no history of cancer (HR = 1.36, 95% CI = 1.10-1.68). The association of 10 to 13 years of use, compared with 2 years of use, was not statistically significant for hip (HR = 1.66, 95% CI = 0.81-3.40), clinical vertebral (HR = 1.65, 95% CI = 0.99-2.76), or wrist fracture (HR = 1.16, 95% CI = 0.67-2.00).

CONCLUSION

In older women at high risk of fracture, 10 to 13 years of bisphosphonate use was associated with higher risk of any clinical fracture than 2 years of use. These results add to concerns about the benefit of very long-term bisphosphonate use.

Predicting Future Hip Fractures on Routine Abdominal CT Using Opportunistic Osteoporosis Screening Measures: A Matched Case-Control Study

OBJECTIVE

Hip fracture is a major consequence of low bone mineral density, which is treatable but underdiagnosed. The purpose of this case-control study is to determine whether lumbar vertebral trabecular attenuation, vertebral compression fractures, and femoral neck T scores readily derived from abdominopelvic CT scans obtained for various indications are associated with future hip fragility fracture.

MATERIALS AND METHODS

A cohort of 204 patients with hip fracture (130 women and 74 men; mean age, 74.3 years) who had undergone abdominopelvic CT before fracture occurred (mean interval, 24.8 months) was compared with an age- and sex-matched control cohort without hip fracture. L1 trabecular attenuation, vertebral compression fractures of grades 2 and 3, and femoral neck T scores derived from asynchronous quantitative CT were recorded. The presence of one or more clinical risk factor for fracture was also recorded. Multivariate logistic regression models were used to determine the association of each measurement with the occurrence of hip fracture.

RESULTS

The mean L1 trabecular attenuation value, the presence of one or more vertebral compression fracture, and CT-derived femoral neck T scores were all significantly different in patients with hip fracture versus control subjects (p < 0.01). Logistic regression models showed a significant association of all measurements with hip fracture outcome after adjustments were made for age, sex, and the presence of one or more clinical risk factor. L1 trabecular attenuation and CT-derived femoral neck T scores showed moderate accuracy in differentiating case and control patients (AUC, 0.70 and 0.78, respectively).

CONCLUSION

L1 trabecular attenuation, CT-derived femoral neck T scores, and the presence of at least one vertebral compression fracture on CT are all associated with future hip fragility fracture in adults undergoing routine abdominopelvic CT for a variety of conditions.

Long-term oral bisphosphonate use in relation to fracture risk in postmenopausal women with breast cancer: findings from the Women's Health Initiative

OBJECTIVE

The aim of the study was to examine the association of long-term oral bisphosphonate use, compared with short-term use, with fracture risk among postmenopausal women with breast cancer.

METHODS

We studied 887 postmenopausal women who were enrolled to the Women's Health Initiative from 1993 to 1998, diagnosed with breast cancer after enrollment, and reported current oral bisphosphonate use of 2 years or more on a medication inventory administered in 2008 to 2009. The outcome of any clinical fracture was ascertained by self-report on an annual study form; a subset of fractures was confirmed with medical records. Women were followed from completion of the medication inventory until 2014. The association between duration of bisphosphonate use reported on the medication inventory and fracture was estimated using multivariate Cox proportional hazards survival models that compared 4 to 7 years and 8 or more years of bisphosphonate use with 2 to 3 years of use.

RESULTS

On average, women were 76 years of age and were followed for 3.7 (SD 1.1) years. There were 142 clinical fractures. In the multivariate-adjusted analysis for fracture risk factors, 8 or more years of bisphosphonate use was associated with higher risk of fracture compared with 2 to 3 years of use (hazard ratio, 1.67 [95% CI, 1.06-2.62]). There was no significant association of 4 to 7 years of use with fracture.

CONCLUSIONS

Bisphosphonate use of 8 or more years was associated with higher risk of any clinical fracture compared with 2 to 3 years of use. Our findings raise concern about potential harm or decreased effectiveness of long-term bisphosphonate use on fracture risk. The findings warrant confirmatory studies.

Non-adherence with bisphosphonates among patients with osteoporosis: impact on fracture risk and healthcare cost‏

Osteoporosis-related fractures at the spine and hip have a substantial impact on mortality, morbidity, and quality of life in older adults worldwide. Adherence to bisphosphonates is essential for effective treatment and fracture prevention. Nevertheless, numerous studies from various populations and study designs clearly indicated that adherence and persistence are poor with more than 50% of patients discontinuing therapy within one year. This is primarily explained by mild adverse effects, dosing regimens, and costs. Studies have also shown that good adherence is associated with reduced osteoporosis-related and non-related healthcare costs as soon as 2 years from therapy initiation. Nonetheless, we found only little improvement in adherence rates over the years. In light of the importance of medication adherence and the limited success of previous programs, other than reducing dosing frequency, new directions should be explored to engage patients and care givers in order to improve adherence and prevent fractures.

Orthopedic complications in diabetes

Diabetes is associated with a number of lower extremity orthopedic conditions and complications including fractures, Charcot neuroarthropathy, plantar ulcers, and infection. These complications are of significant clinical concern in terms of morbidity, mortality, and socioeconomic costs. A review of each condition is discussed, with particular emphasis on the clinical importance, diagnostic considerations, and orthopedic treatment recommendations. The goal of the article is to provide a clinical picture of the challenges that orthopedic surgeons confront, and highlight the need for specific clinical guidelines in diabetic patients.

Patterns of bisphosphonates utilization in patients under age 45 in a large cohort of commercial insurance beneficiaries in the United States

Background

The effectiveness and safety of bisphosphonates treatment used in the young population have not been well studied. Despite insufficient data on effectiveness and safety of bisphosphonates in young patients, bisphosphonates are still considered in younger patients at high risk for osteoporosis or fracture. The objectives of this study were to identify bisphosphonate initiators aged 10–45 years and describe their clinical characteristics and to assess time trends of bisphosphonate use over the past decade in a large U.S. population-based cohort.

Methods

Using the medical and pharmacy claims data from a U.S. commercial insurance (2003–2012), patients aged 10–45 years without malignancy who initiated an oral or intravenous bisphosphonate after at least 1 year of insurance enrollment were selected. Baseline demographics, comorbidities, medications and health care utilization were assessed in the year prior to initiating a bisphosphonate. The trend of bisphosphonate use over time was examined.

Results

There were 9,082 bisphosphonate initiators (0.02% of the same age group in the population). The mean age was 38.1 years and 79.6% female. Osteoporosis was the most common diagnosis (41.2%). At baseline, 10.8% had a diagnosis of fracture and 29.0% had a bone mineral density measured. Of those who used glucocorticoids (39%) at baseline, the mean 1-year cumulative prednisone-equivalent dose was 2,669 milligrams. The use of bisphosphonates in the young population significantly decreased over the past decade (p<0.001).

Conclusions

Among young patients aged 10–45, the use of bisphosphonates was uncommon and significantly decreased over the past decade in the U.S. While most patients initiating bisphosphonates had a diagnosis of osteoporosis and fracture in the preceding year, some had no recorded claims with a diagnosis of fracture, osteoporosis, or long-term glucocorticoids use at baseline. Future research is needed to examine the effectiveness and safety of bisphosphonates in young patients at risk for osteoporosis.

Questioning the association between bisphosphonates and atypical femoral fractures

Bisphosphonates are the first-line treatment for osteoporosis. Structurally, they are stable analogues of pyrophosphate and therefore exhibit a high affinity for bone mineral. They reduce bone loss by attenuating the ability of the osteoclast to resorb bone, decreasing activation frequency, and the rate of remodeling. Large prospective randomized placebo-control trials provide unequivocal evidence for a reduction in the incidence of fractures. Impressively, 40 years since their first use in patients, the safety profile of bisphosphonates has been equally reassuring. Questions have arisen lately as to whether bisphosphonates could cause atypical fractures, a rare type of atraumatic or minimal trauma femur fracture occurring below the great trochanter. This question has prompted calls for a broader examination of the long-term effects of bisphosphonate use. An attempt by the Food and Drug Administration to garner consensus and provide definitive views was not successful. This has led to continued anxiety among treating physicians and patients alike, resulting in an overall reduction in prescriptions for bisphosphonates and for osteoporosis therapies in general. Here, we provide an overview of the current data on atypical fractures and bisphosphonate use.

Adherence to oral bisphosphonates and the risk of subtrochanteric and femoral shaft fractures among female medicare beneficiaries

Previous studies have shown an association between duration of bisphosphonate use and atypical femur fractures. This cohort study showed an increasingly higher risk of subtrochanteric and femoral shaft fractures among those who were more adherent to oral bisphosphonates.

INTRODUCTION

Long-term use of oral bisphosphonates has been implicated in an increased risk of atypical femur fractures located in subtrochanteric and femoral shaft regions. Another measure of drug exposure, medication adherence, however, has not been investigated.

METHODS

Among all Medicare fee-for-service female beneficiaries from 2006-2010, we followed 522,287 new bisphosphonate users from their index prescription until being censored or having a primary diagnosis of closed subtrochanteric/femoral shaft or intertrochanteric/femoral neck fractures. Data about radiographs of fracture site and features were not available. Adherence was classified according to the medication possession ratio (MPR) as the following: MPR < 1/3 as less compliant, MPR ≥ 1/3- < 2/3 as compliant, and MPR ≥ 2/3 as highly compliant. Alternative cutoff points at 50 and 80% were also used. Survival analysis was used to determine the cumulative incidence and hazard of subtrochanteric/femoral shaft or intertrochanteric/femoral neck fractures.

RESULTS

There was a graded increase in incidence of subtrochanteric/femoral shaft fractures as the level of adherence increased (Gray's test, P < 0.001). The adjusted hazard ratio (HR) for the highly compliant vs. the less compliant was 1.23 (95% Confidence Interval [CI] 1.06-1.43) overall, became significant after 2 years of follow-up (HR = 1.51, 95% CI 1.06-2.15) and reached the highest risk in the fifth year (HR = 4.06, 95% CI 1.47-11.19). However, age-adjusted incidence rates of intertrochanteric/femoral neck fractures were significantly lower among highly compliant beneficiaries, compared to less compliant users (HR = 0.69, 95% CI 0.66-0.73). Similar results were obtained when the cutoff points for being compliant and highly compliant were set at 50 and 80 %, respectively.

CONCLUSIONS

Subtrochanteric/femoral shaft fractures, unlike intertrochanteric/femoral neck fractures, are positively associated with higher adherence to long-term (≥3 years) oral bisphosphonates in the elderly female Medicare population.

How long should we treat?

Osteoporosis is a chronic disease, for which effective drugs are available. These drugs have reduced the risk of osteoporosis-related fractures in robust trials of 3-5 years duration. There is no evidence of anti-fracture efficacy for treatments of longer duration. The consequences of stopping treatments are very different for the different molecules. Bisphosphonates can be safely discontinued after 3-5 years of treatment if there was optimal adherence and if patients are no longer osteoporotic. This discontinuation cannot be applied in patients with recent fractures or for other treatments. Safety of prolonged treatment is a huge concern which must be managed appropriately. The decision of a prolonged treatment is driven by the underlying risk of fracture. This risk must be assessed regularly in order to share with the patient the benefit-risk ratio of prolonged treatment.

Association between teriparatide adherence and healthcare utilization and costs among hip fracture patients in the United States

PURPOSE

This study examined the association between teriparatide (TPTD) adherence, and healthcare utilization and costs among hip fracture (HFx) patients.

METHODS

Individuals aged 50years and older with an HFx between 1/1/2002-12/31/2010 were identified from a large US administrative claims database. The first HFx date during this period was designated as the index. Selected patients had at least 6months of pre-index continuous enrollment (baseline) and no baseline TPTD use, cancer, or Paget's disease. Patients initiating TPTD post-index were followed until censoring at switch to bisphosphonates, disenrollment, 36months post-index, or diagnosis of cancer or Paget's disease. Teriparatide adherence was measured as the proportion of days covered (PDC) by TPTD prescriptions, during the follow-up period, to construct three adherence groups: low (PDC≤0.5), medium (0.5<PDC≤0.8), and high (PDC>0.8) adherence. Outcome measures were repeated HFx, number of inpatient admissions, and per-patient-per-month (PPPM) healthcare costs. Multivariable generalized linear models examined the association between the TPTD adherence groups and the outcomes, adjusting for cross-group differences in patient characteristics.

RESULTS

A total of 824 patients (mean age 75years, 90% female) were included: 30% low, 27% medium, and 44% high adherence. In multivariable analyses, high adherence was significantly (all p<0.05) directly associated with increased PPPM pharmacy costs ($621 low, $1093 medium, and $1572 high), but also with the lowest inpatient ($963 low, $960 medium, and $629 high) and outpatient ($1087 low, $1068 medium, and $776 high) costs, leading to the highest total costs in the medium adherence group but similar costs in the high and low adherence groups ($2599 low, $3163 medium, and $2869 high). The high adherence group also had the lowest number of inpatient admissions.

CONCLUSIONS

Significantly increased pharmacy costs associated with the high TPTD adherence group were offset by significantly fewer inpatient admissions, fewer repeated HFx, and lower inpatient and outpatient costs.

Diagnosis and treatment of bisphosphonate-induced atypical femoral fractures

Atypical femoral fractures, deformities of the subtrochanteric region of the femur identified with plain anteroposterior or lateral lower extremity radiographs and characterized by a specific fracture pattern, are uncommon manifestations in osteoporotic patients. However, the high prevalence of these fractures in patients receiving long-term bisphosphonate therapy led to the many investigations of this association. The purpose of this article is to evaluate and address the link between this fracture type with long-term bisphosphonate therapy, outline the clinical scenario and better define treatment options for optimal care and recovery. In order to do this, a PubMed search was carried out for significant articles using the following keywords: ‘alendronate’, ‘fracture’, ‘atypical’ and ‘femur’.