Predicting Adherence and Persistence with Oral Bisphosphonate Therapy in an Integrated Health Care Delivery System

Clinical practice guidelines for full-cycle standardized management of bone health in breast cancer patients

Bone health management for breast cancer spans the entire cycle of patient care, including the prevention and treatment of bone loss caused by early breast cancer treatment, the adjuvant application of bone-modifying agents to improve prognosis, and the diagnosis and treatment of advanced bone metastases. Making good bone health management means formulating appropriate treatment strategies and dealing with adverse drug reactions, and will help to improve patients' quality of life and survival rates. The Breast Cancer Expert Committee of the National Cancer Center for Quality Control organized relevant experts to conduct an in-depth discussion on the full-cycle management of breast cancer bone health based on evidence-based medicine, and put forward reasonable suggestions to guide clinicians to better deal with health issues in bone health clinics.

The clinician's guide to prevention and treatment of osteoporosis

Osteoporosis is the most common metabolic bone disease in the USA and the world. It is a subclinical condition until complicated by fracture(s). These fractures place an enormous medical and personal burden on individuals who suffer from them and take a significant economic toll. Any new fracture in an adult aged 50 years or older signifies imminent elevated risk for subsequent fractures, particularly in the year following the initial fracture. What a patient perceives as an unfortunate accident may be seen as a sentinel event indicative of bone fragility and increased future fracture risk even when the result of considerable trauma. Clinical or subclinical vertebral fractures, the most common type of osteoporotic fractures, are associated with a 5-fold increased risk for additional vertebral fractures and a 2- to 3-fold increased risk for fractures at other sites. Untreated osteoporosis can lead to a vicious cycle of recurrent fracture(s), often resulting in disability and premature death. In appropriate patients, treatment with effective antifracture medication prevents fractures and improves outcomes. Primary care providers and medical specialists are critical gatekeepers who can identify fractures and initiate proven osteoporosis interventions. Osteoporosis detection, diagnosis, and treatment should be routine practice in all adult healthcare settings. The Bone Health and Osteoporosis Foundation (BHOF) - formerly the National Osteoporosis Foundation - first published the Clinician's Guide in 1999 to provide accurate information on osteoporosis prevention and treatment. Since that time, significant improvements have been made in diagnostic technologies and treatments for osteoporosis. Despite these advances, a disturbing gap persists in patient care. At-risk patients are often not screened to establish fracture probability and not educated about fracture prevention. Most concerning, the majority of highest risk women and men who have a fracture(s) are not diagnosed and do not receive effective, FDA-approved therapies. Even those prescribed appropriate therapy are unlikely to take the medication as prescribed. The Clinician's Guide offers concise recommendations regarding prevention, risk assessment, diagnosis, and treatment of osteoporosis in postmenopausal women and men aged 50 years and older. It includes indications for bone densitometry as well as fracture risk thresholds for pharmacologic intervention. Current medications build bone and/or decrease bone breakdown and dramatically reduce incident fractures. All antifracture therapeutics treat but do not cure the disease. Skeletal deterioration resumes sooner or later when a medication is discontinued-sooner for nonbisphosphonates and later for bisphosphonates. Even if normal BMD is achieved, osteoporosis and elevated risk for fracture are still present. The diagnosis of osteoporosis persists even if subsequent DXA T-scores are above - 2.5. Ongoing monitoring and strategic interventions will be necessary if fractures are to be avoided. In addition to pharmacotherapy, adequate intake of calcium and vitamin D, avoidance of smoking and excessive alcohol intake, weight-bearing and resistance-training exercise, and fall prevention are included in the fracture prevention armamentarium. Where possible, recommendations in this guide are based on evidence from RCTs; however, relevant published data and guidance from expert clinical experience provides the basis for recommendations in those areas where RCT evidence is currently deficient or not applicable to the many osteoporosis patients not considered for RCT participation due to age and morbidity.

Risk of complete atypical femur fracture with Oral bisphosphonate exposure beyond three years

Background

Bisphosphonate (BP) therapy has been associated with atypical femur fracture (AFF). However, the threshold of treatment duration leading to increased AFF risk is unclear. In a retrospective cohort of older women initiating BP, we compared the AFF risk associated with treatment for at least three years to the risk associated with treatment less than three years.

Methods

We used observational data from a large population of female members of an integrated healthcare system who initiated oral BP during 2002–2014. Women were retrospectively followed for incident AFF confirmed by radiologic adjudication. Demographic data, pharmacologic exposures, comorbidity, bone density, and fracture history were ascertained from electronic health records. Inverse probability weighting was used to estimate risk differences comparing the cumulative incidence (risk) of AFF if women discontinued BP within three years to the cumulative incidence of AFF if women continued BP for three or more years, adjusting for potential time-dependent confounding by the aforementioned factors.

Results

Among 87,820 women age 45–84 years who initiated BP (mean age 68.6, median T-score − 2.6, 14% with prior major osteoporotic fracture), 16,180 continued BP for three or more years. Forty-six confirmed AFFs occurred during follow-up in the two groups. AFF-free survival was greater for BP treatment < 3 years compared to treatment ≥3 years (p = 0.004 comparing areas under survival curves). At five years, the risk of AFF was 27 per 100,000 (95% confidence interval, CI: 8–46) if women received BP treatment < 3 years and 120 per 100,000 (95% CI: 56–183) if women received BP treatment ≥3 years (risk difference 93 per 100,000, 95% CI: 30–160). By ten years, the risks were 27 (95% CI: 8–46) and 363 (95% CI: 132–593) per 100,000 for BP treatment < 3 and ≥ 3 years, respectively (risk difference 336 per 100,000, 95% CI: 110–570).

Conclusions

Bisphosphonate treatment for 3 or more years was associated with greater risk of AFF than treatment for less than 3 years. Although AFFs are uncommon among BP-treated women, this increased risk should be considered when counseling women about long-term BP use. Future studies should further characterize the dose-response relationship between BP duration and incident AFF and identify patients at highest risk.

Bisphosphonate Treatment Beyond 5 Years and Hip Fracture Risk in Older Women

IMPORTANCE

Clinical trials have demonstrated the antifracture efficacy of bisphosphonate drugs for the first 3 to 5 years of therapy. However, the efficacy of continuing bisphosphonate for as long as 10 years is uncertain.

OBJECTIVE

To examine the association of discontinuing bisphosphonate at study entry, discontinuing at 2 years, and continuing for 5 additional years with the risk of hip fracture among women who had completed 5 years of bisphosphonate treatment at study entry.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included women who were members of Kaiser Permanente Northern and Southern California, 2 integrated health care delivery systems, and who had initiated oral bisphosphonate and completed 5 years of treatment by January 1, 2002, to September 30, 2014. Data analysis was conducted from January 2018 to August 2020.

EXPOSURE

Discontinuation of bisphosphonate at study entry (within a 6-month grace period), discontinuation at 2 years (within a 6-month grace period), and continuation for 5 additional years.

MAIN OUTCOMES AND MEASURES

The outcome was hip fracture determined by principal hospital discharge diagnoses. Demographic, clinical, and pharmacological data were ascertained from electronic health records.

RESULTS

Among 29 685 women (median [interquartile range] age, 71 [64-77] years; 17 778 [60%] non-Hispanic White individuals), 507 incident hip fractures were identified. Compared with bisphosphonate discontinuation at study entry, there were no differences in the cumulative incidence (ie, risk) of hip fracture if women remained on therapy for 2 additional years (5-year risk difference [RD], -2.2 per 1000 individuals; 95% CI, -20.3 to 15.9 per 1000 individuals) or if women continued therapy for 5 additional years (5-year RD, 3.8 per 1000 individuals; 95% CI, -7.4 to 15.0 per 1000 individuals). While 5-year differences in hip fracture risk comparing continuation for 5 additional years with discontinuation at 2 additional years were not statistically significant (5-year RD, 6.0 per 1000 individuals; 95% CI, -9.9 to 22.0 per 1000 individuals), interim hip fracture risk appeared lower if women discontinued after 2 additional years (3-year RD, 2.8 per 1000 individuals; 95% CI, 1.3 to 4.3 per 1000 individuals; 4-year RD, 9.3 per 1000 individuals; 95% CI, 6.3 to 12.3 per 1000 individuals) but not without a 6-month grace period to define discontinuation.

CONCLUSIONS AND RELEVANCE

In this study of women treated with bisphosphonate for 5 years, hip fracture risk did not differ if they discontinued treatment compared with continuing treatment for 5 additional years. If women continued for 2 additional years and then discontinued, their risk appeared lower than continuing for 5 additional years. Discontinuation at other times and fracture rates during intervening years should be further studied.

Determinants of Oral Bisphosphonate Use Beyond 5 Years

BACKGROUND

Few studies have examined factors that determine bisphosphonate (BP) continuation beyond 5 years in clinical practice.

OBJECTIVE

To investigate factors associated with BP continuation among women who completed 5 years of BP therapy.

METHODS

Women who received 5 consecutive years of oral BP treatment entered the cohort during 2002-2014 and were followed up to 5 additional years. Multivariable logistic regression was used to evaluate the association of demographic and clinical factors with adherent treatment continuation.

RESULTS

The cohort included 19,091 women with a median age of 72 years. Baseline and time-varying factors associated with increased odds of BP continuation after 5 years were (a) most recent bone mineral density (BMD) T-score -2 to -2.4 (OR = 1.31, 95% CI = 1.25-1.38), T-score -2.5 to -2.9 (OR = 1.48, 95% CI = 1.39-1.57), and T-score ≤ -3.0 (OR = 1.57, 95% CI = 1.47-1.68) versus T-scores above -2.0; (b) index date before 2008 (OR =1.35, 95% CI = 1.29-1.41); and (c) diabetes mellitus (OR = 1.08, 95% CI = 1.01-1.16). In contrast, factors associated with decreased odds of BP continuation were (a) recent hip (OR = 0.61, 95% CI = 0.52-0.71) or humerus (OR = 0.79, 95% CI = 0.66-0.94) fracture or fracture other than hip, wrist, spine, or humerus (OR = 0.90, 95% CI = 0.84-0.97); (b) Charlson Comorbidity Index score > 2 (OR = 0.91, 95% CI = 0.84-0.98); (c) history of rheumatoid arthritis (OR = 0.89, 95% CI = 0.80-0.99); (d) Hispanic (OR = 0.89, 95% CI=0.85-0.94) or Asian (OR = 0.90, 95% CI = 0.85-0.94) race/ethnicity; and (e) use of proton pump inhibitors (OR = 0.65, 95% CI = 0.59-0.71). Patient age and fracture before BP initiation were not associated with treatment continuation.

CONCLUSIONS

Clinical factors predicting continued BP treatment beyond 5 years include low BMD T-score, absence of recent fracture, and earlier era of treatment. Use of proton pump inhibitors was associated with lower likelihood of BP continuation. Other clinical and demographic factors were also noted to have variable effects on BP treatment continuation.

DISCLOSURES

This study was supported by a grant from the National Institute on Aging and National Institute of Arthritis, Musculoskeletal and Skin Diseases at the National Institutes of Health (NIH; R01AG047230, S1). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or Kaiser Permanente. Lo has received previous research funding from Amgen and Sanofi, unrelated to the current study. Adams has received previous research funding from Merck, Amgen, Otsuka, and Radius Health, unrelated to the current study. Ettinger has served as an expert witness for Teva Pharmaceuticals, unrelated to the current study. Ott previously attended a scientific advisory meeting for Amgen but declined the honorarium. The other authors have nothing to disclose. These data were presented at the 2018 Annual Meeting of the American Society of Bone and Mineral Research (ASBMR), September 28-October 1, 2018, Montreal, Quebec, Canada.

The Epidemiology of Metatarsal Fractures Among Older Females With Bisphosphonate Exposure

Bisphosphonates (BP) are used to treat osteoporosis, although rare atypical femur fractures have occurred with long-term exposure, especially among Asians. Metatarsal fractures have also been reported with atypical femur fracture. We examined the epidemiology of metatarsal fractures among 48,390 females aged ≥50 years who initiated oral BP and were followed for a median 7.7 years, including 68 females who experienced an atypical femur fracture. Incident metatarsal fractures after BP initiation were identified by clinical diagnoses and validated by record review. The association of BP, clinical risk factors, race/ethnicity, and metatarsal fracture was examined by using Cox proportional hazard analyses. Among 1123 females with incident metatarsal fracture, 61.0% had an isolated fifth metatarsal fracture. The incidence of metatarsal fracture was 312 per 100,000 person-years of follow-up and was substantially lower for Asians. The adjusted relative rate for metatarsal fractures was 0.5 (95% confidence interval 0.4 to 0.6) for Asians compared with whites. Younger age, prior fracture, other risk factors, and current BP were associated with an increased relative rate of metatarsal fracture, but BP duration was not. Females with atypical femur fracture were not more likely to experience metatarsal fracture (2.9% versus 2.3%, p = .7), but only 68 females had an atypical fracture and stress fracture of the metatarsals was not examined. Except for age, the demographic profile for metatarsal fracture after initiating BP was similar to that for osteoporotic fracture, with Asians at a much lower risk. Although metatarsal fractures were not associated with BP duration or atypical femur fracture, the subset of metatarsal stress fractures was not specifically examined.

Atypical femur fracture incidence in women increases with duration of bisphosphonate exposure

In a northern California population of older women who were treated with oral bisphosphonate drugs, the incidence of atypical femur fracture, a rare complication of treatment, increased with longer duration of bisphosphonate exposure. These findings align with those previously reported in an independent southern California population.

INTRODUCTION

The age-adjusted incidence of atypical femur fracture (AFF) reported in southern California increased with bisphosphonate (BP) exposure, ranging up to 113 per 100,000 person-years for 8-10-year exposure. This study examines the incidence of AFF in a northern California population.

METHODS

Women age 45-89 years who initiated oral BP during 2002-2014 in Kaiser Permanente Northern California were followed for AFF outcome, defined by a primarily transverse diaphyseal femur fracture through both cortices, with focal periosteal/endosteal hypertrophy, minimal trauma, and minimal/no comminution. Total BP exposure was determined from dispensed prescriptions. The incidence of AFF, calculated for 2-year BP categories ranging from < 2 to > 10 years, was age-adjusted using the 2000 US Census.

RESULTS

Among 94,542 women, 107 experienced an AFF during or < 1 year after BP cessation (mean exposure 6.6 ± 3.0 years and total days' supply 5.7 ± 2.8 years at AFF). A strong relationship between AFF incidence and increasing BP exposure was seen, more than doubling for each 2-year category until 8-10 years. Among women with 2- to < 4-year BP, the crude and age-adjusted incidence was 18 and 9 per 100,000 person-years but increased over 2- and 5-fold for women with 4- to < 6- and 6- to < 8-year BP, respectively. For those receiving ≥ 8-year BP, the crude and age-adjusted incidence peaked at 196 and 112 per 100,000 person-years exposure.

CONCLUSION

Incidence of AFF increases markedly after 4-6 years of BP. These trends align with southern California and confirm a strong BP duration-related risk of this rare but serious event.

Patients' reasons for adhering to long-term alendronate therapy

We aimed to determine patients' reasons for continuing alendronate therapy over 5 years by administering a questionnaire. Bone mineral density, fractures, drugs, Charlson comorbidity index, and lifestyle factors were also considered. Education and awareness of the disease appeared highly associated with good alendronate adherence while worsening health status with discontinuation.

INTRODUCTION

Aim of this study was to investigate patients' reasons for adhering to long-term alendronate therapy (more than 5 years), as data is not available in the current literature regarding the reasons behind long-term adherence.

METHODS

We studied 204 long-term adherent alendronate users: 65 postmenopausal outpatients still adherent (group C, years on treatment = 8.70 ± 1.31) were compared to 139 age-matched patients who discontinued therapy (group S, years on treatment = 8.64 ± 1.43). We evaluated main biochemical parameters, BMD values, fractures, and Charlson comorbidity index (CCI). A questionnaire was administered to analyze the reasons for long-term adherence.

RESULTS

There were no significant differences between groups concerning baseline DXA values, number of fractures, and CCI. A higher education level was observed in group C (C 54% vs S 35% of patients, p = 0.001). At the time of interview, there was a significantly higher number of patients with a CCI of two in group S compared to the beginning of treatment (56% vs 43%, p = 0.04), together with a higher number of patients taking more than 3 drugs (22% vs 11%, p = 0.01) compared to basal evaluation. Forty-seven percent of patients reported new diseases during the treatment as the main reason for stopping alendronate. A multivariate, stepwise logistic regression analysis showed that awareness of the disease was highly associated with adherence (OR = 0.20; 95% CI 0.045-0.93, p = 0.04) followed by higher education (OR = 0.526, 95% CI 0.345-0.801, p = 0.003). Worsening of CCI was associated with discontinuation (OR = 2.75, 95% CI 1.033-7.324, p = 0.04).

CONCLUSIONS

Education and disease awareness are associated with long-term alendronate adherence while competing health problems negatively impact adherence.

Using Pharmacy Data and Adherence to Define Long-Term Bisphosphonate Exposure in Women

BACKGROUND

Assigning drug exposure is a necessary first step in examining bisphosphonate (BP) treatment in observational studies using pharmacy data.

OBJECTIVE

To determine whether the choice of adherence level using the proportion of days covered (PDC) affected BP exposure assignment.

METHODS

10,381 female health plan members who initiated oral BP therapy between 2002 and 2010 and had received 5 consecutive years of treatment were identified and subsequently followed up to 5 additional years. In each 90-day interval of follow-up, a woman was considered "on treatment" if she received the drug for more than a predetermined PDC based on pharmacy days supply and "off treatment" if she received the drug for less than that PDC. Women who continued on therapy above the PDC threshold during follow-up were considered continuously on therapy. Women who were off treatment during the first 90-days of follow-up were classified as off therapy and were followed to determine if they remained continuously off treatment. This study evaluated the extent to which varying the PDC threshold (≥ 0.5, ≥ 0.6, and ≥ 0.7) affected the proportion of women classified as "continuously on" or "continuously off" BP during follow-up.

RESULTS

Under PDC thresholds of 0.5, 0.6, and 0.7, 48%, 43%, and 36% of women who remained on follow-up were categorized as continuously on treatment at year 2 of follow-up, and 18%, 14%, and 12% were categorized as continuously on treatment by the end of follow-up. Using these same PDC thresholds, 9%, 12%, and 15% of women were categorized as off therapy during the first quarter of follow-up and were highly likely to remain off therapy: 4%, 5%, and 5% were classified as continuously off therapy at year 2, and 4% of women were classified as such by the end of follow-up for all 3 thresholds.

CONCLUSIONS

A PDC of 0.6 was chosen as a practical threshold for drug adherence. Varying the PDC to 0.5 or 0.7 resulted in modest changes in the proportions of women considered continuously on BP therapy.

DISCLOSURES

This study was supported by a grant from the National Institute of Aging and National Institute of Arthritis, Musculoskeletal and Skin Diseases at the National Institutes of Health (R01AG047230, S1). Lo has received previous research funding from Amgen and Sanofi, outside of the current study. Chandra has received previous research funding from Amgen outside of the current study. Adams has received previous research funding from Merck, Amgen, Otsuka, and Radius Health, outside of the current study. Ott previously attended a scientific advisory meeting for Amgen but declined the honorarium. Ettinger previously served as an expert witness for Teva Pharmaceuticals.

A systematic review of factors affecting medication adherence among patients with osteoporosis

The aim of this review was to identify factors that influence patients' adherence to anti-osteoporotic therapy. Factors identified that were associated with poorer medication adherence included polypharmacy, older age, and misconceptions about osteoporosis. Physicians need to be aware of these factors so as to optimize therapeutic outcomes for patients.

INTRODUCTION

To identify factors that influence patients' adherence to anti-osteoporotic therapy.

METHODS

A systematic review of literature was performed for articles published up till January 2018 using PubMed®, PsychINFO®, Embase®, and CINAHL®. Peer-reviewed articles which examined factors associated with anti-osteoporotic medication adherence were included. Classes of anti-osteoporotic therapy included bisphosphonates, parathyroid hormone-related analogue, denosumab, selective estrogen receptor modulators, estrogen/progestin therapy, calcitonin, and strontium ranelate. Meta-analyses, case reports/series, and other systematic reviews were excluded. Identified factors were classified using the World Health Organization's five dimensions of medication adherence (condition, patient, therapy, health-system, and socio-economic domains).

RESULTS

Of 2404 articles reviewed, 124 relevant articles were identified. The prevalence of medication adherence ranged from 12.9 to 95.4%. Twenty-four factors with 139 sub-factors were identified. Bisphosphonates were the most well-studied class of medication (n = 59, 48%). Condition-related factors that were associated with poorer medication adherence included polypharmacy, and history of falls was associated with higher medication adherence. Patient-related factors which were associated with poorer medication adherence included older age and misconceptions about osteoporosis while therapy-related factors included higher dosing frequency and medication side effects. Health system-based factors associated with poorer medication adherence included care under different medical specialties and lack of patient education. Socio-economic-related factors associated with poorer medication adherence included current smoker and lack of medical insurance coverage.

CONCLUSION

This review identified factors associated with poor medication adherence among osteoporotic patients. To optimize therapeutic outcomes for patients, clinicians need to be aware of the complexity of factors affecting medication adherence.