Differences in persistence among different weekly oral bisphosphonate medications

Surveillance of drug prescribing: why outliers miss their targets - a qualitative study

BACKGROUND

Rising costs are a challenge for healthcare systems. To keep expenditure for drugs under control, in many healthcare systems, drug prescribing is continuously monitored. The Bavarian Drug Agreement (German: Wirkstoffvereinbarung or WSV) for the ambulatory sector in Bavaria (the federal state of Germany) was developed for this purpose. Physicians must reach defined drug target quotas for prescribing generic drugs and certain recommended drugs specified and measured with defined daily doses (DDD). A subgroup of physicians, known as outliers, may miss their drug targets. The objective of this qualitative study was to understand the reasons physicians miss their targets.

METHODS

We identified outliers based on drug prescribing data from the association of statutory health insurance (SHI)-accredited physicians (KV). Outliers were invited to participate in semi-structured interviews.

RESULTS

Out of 401 outliers thus identified n = 26 physicians were interviewed. Their prescribing behaviours are affected by competing demands regarding drug decisions, such as saving staff time, costs, and discussions with patients. Often, their freedom to prescribe is limited by previous prescribers. Ease of administration of drugs not recommended also plays a role. Uncritical enthusiasm regarding the effectiveness and safety of drugs with recommendations, often reinforced by pharmaceutical marketing, leads to missed targets. Some physicians have coping strategies to avoid becoming outliers.

CONCLUSIONS

Investigating physicians not meeting their targets helps us understand beliefs and barriers for appropriate drug prescribing. Based on these kinds of findings, surveillance procedures can be improved, and physicians can receive support to meet targets in the future.

TRIAL REGISTRATION

This trial has been registered in the German Register of Clinical Trials (DRKS: DRKS00016161; registration date 07. December 2018).

Comparing the efficacies of bisphosphonates' therapies for osteoporosis persistence and compliance: A Systematic Review

OBJECTIVES

Osteoporosis is the most prevalent metabolic bone disorder worldwide. This review was undertaken to compare the efficacies of bisphosphonates therapies for patient persistence and compliance for the treatment of osteoporosis.

METHODS

A systematic review was performed in accordance with the available reporting items. MEDLINE and Cochrane library databases were applied for literature searched up to January 2020. All major studies such as prospective, retrospective and reviews articles that examined patient persistence or compliance to bisphosphonates for osteoporosis were included.

RESULTS

Literature search found 656 relevant published reports, out of which 87 were included. The 10,712,176 osteoporotic patients were studied for patient persistence and 5,875,718 patients were studied for patient compliances. Analysis of all studied bisphosphonates showed almost similar patterns for patient persistence rates as it was decreased over the time following initial prescription but persistence length was found to be significantly high for alendronate therapy as compared to the other studied bisphosphonates (p<0.001), whereas the length of persistence of all other bisphosphonates (other than alendronate) were almost same (p>0.05). Analysis of patient compliances with etidronate therapy showed the highest percent medication possession ratio (MRP) at 12 months, followed by the MRPs of ibandronate, alendronate, risedronate, and clodronate.

CONCLUSIONS

This is the first systematic review that shows the comparison of the efficiencies of bisphosphonates for patient persistence and compliance for the treatment of osteoporosis. The data showed that the length of patient persistence was highest for alendronate therapy, whereas patient compliance was highest for etidronate therapy for the treatment of osteoporosis.

Adherence with brand versus generic bisphosphonates among osteoporosis patients: a new-user cohort study in the French National Healthcare Insurance database

Several studies documented declines in treatment adherence with generic forms of oral bisphosphonates in osteoporosis compared to branded forms, while others did not support this relation. Our aim was to compare medication adherence with brand versus generic forms of oral bisphosphonates. A new-user cohort study was conducted using routinely collected administrative and healthcare data linked at the individual level extracted from a nationwide representative sample of the French National Healthcare Insurance database. We included all patients aged 50 and older, new users of oral bisphosphonates for primary osteoporosis between 01/01/2009 and 31/12/2015. Two components of adherence were measured: implementation (continuous multiple-interval measure of medication availability version 7; CMA7) and persistence (time to discontinuation). The sample was composed of 1,834 in the "brand bisphosphonate" group and 1,495 patients in the "generic bisphosphonate" group. Initiating oral bisphosphonate treatment with brand was associated with a higher risk of discontinuation within 12 months (Hazard Ratio = 1.08; 95%CI = [1.02;1.14]). The risk of good implementation (CMA7 ≥ 0.90) was significantly lower in "brand bisphosphonate" group (Risk Ratio = 0.90; 95%CI = [0.85; 0.95]). We did not find any evidence to support the hypothesis of a lower adherence to generic bisphosphonates. In fact, prescribing of generic bisphosphonates led to a higher persistence rate and to better implementation at 1 year.

Time to benefit and the long-term persistence of new users of oral bisphosphonates

INTRODUCTION

This study aimed to examine long-term persistence in new users of oral bisphosphonates in a population-wide cohort in Manitoba, Canada.

MATERIALS AND METHODS

A longitudinal observational study was conducted using administrative health data characterizing long-term bisphosphonate persistence in those who started treatment between 1997 and 2018. Treatment discontinuation was evaluated using Kaplan-Meier methods. Cox regression was used to examine associations between discontinuation and osteoporosis diagnosis, previous fractures, and age. A sub-analysis of users with FRAX scores examined the relationship between 10-year fracture risk estimations and discontinuation.

RESULTS

Of 42,249 new bisphosphonate users, median age was 71 years, with 88.6% being female. Median duration of bisphosphonate use was 0.95 years (IQR 0.25, 3.9 years). Overall, 47.9% of incident users persisted up to 1 year, 25.0% persisted up to 3 years, and 14.1% up to 5 years. Presence of an indication for bisphosphonate use was associated with decreased discontinuation risk. Persistence generally increased with age. Having a BMD test performed was a predictor of lower discontinuation. The strongest predictor was having an osteoporosis diagnosis [HR for discontinuation = 0.68 (95% CI 0.66, 0.70)]. In users with FRAX scores (n = 14,114), moderate-risk [HR = 0.86 (95% CI 0.77, 0.96)] and high-risk users [HR = 0.77 (95% CI 0.69, 0.85)] were less likely to discontinue compared to lower-risk users.

CONCLUSIONS

A rapid decline in bisphosphonate persistence was shown. Almost half of users would not be expected to achieve clinically relevant benefits with a persistence of less than 1 year. Allowing informed choice in high-risk patients may be the best way to focus on those likely to benefit and persist with treatment.

Real-world persistence and adherence with oral bisphosphonates for osteoporosis: a systematic review

OBJECTIVES

This study examined patient adherence and persistence to oral bisphosphonates for the treatment of osteoporosis in real-world settings.

METHODS

A systematic review was completed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment (HTA) and National Health Service Economic Evaluation Database NHS EED) databases were searched for studies published in English language up to April 2018. Prospective and retrospective observational studies that used prescription claim databases or hospital medical records to examine patient adherence and persistence to oral bisphosphonate treatment among adults with osteoporosis were included. The Newcastle-Ottawa quality assessment scale (NOS) was used to assess the quality of included studies.

RESULTS

The search yielded 540 published studies, of which 89 were deemed relevant and were included in this review. The mean age of patients included within the studies ranged between 53 to 80.8 years, and the follow-up varied from 3 months to 14 years. The mean persistence of oral bisphosphonates for 6 months, 1 year and 2 years ranged from 34.8% to 71.3%, 17.7% to 74.8% and 12.9% to 72.0%, respectively. The mean medication possession ratio ranged from 28.2% to 84.5%, 23% to 50%, 27.2% to 46% over 1 year, 2 years and 3 years, respectively. All studies included scored between 6 to 8 out of 9 on the NOS. The determinants of adherence and persistence to oral bisphosphonates included geographic residence, marital status, tobacco use, educational status, income, hospitalisation, medication type and dosing frequency.

CONCLUSIONS

While a number of studies reported high levels of persistence and adherence, the findings of this review suggest that patient persistence and adherence with oral bisphosphonates medications was poor and reduced notably over time. Overall, adherence was suboptimal. To maximise adherence and persistence to oral bisphosphonates, it is important to consider possible determinants, including characteristics of the patients.

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.

Patient-reported reasons for nonadherence to recommended osteoporosis pharmacotherapy

OBJECTIVES

As many as one-half of patients recommended for osteoporosis pharmacotherapy do not take their medications. To identify intervention targets, we examined patient characteristics associated with nonadherence to recommended pharmacotherapy and their reasons for nonadherence.

METHODS

Data come from the Patient Activation after DXA Result Notification (PAADRN) study, a randomized controlled trial of 7749 patients aged 50 years or older presenting for dual-energy X-ray absorptiometry (DXA) at 3 health centers in the United States. We focused on the 790 patients who reported receiving a recommendation for new pharmacotherapy at baseline. Using Pearson chi-squared tests for categorical variables, 2-sample t tests for continuous variables, and multivariable multinomial logistic regression, we compared those who reported starting the recommended medication (adherers) with temporary nonadherers and nonadherers on demographics, health habits, DXA impression, 10-year probability of fracture using the assessment tool, and osteoporosis knowledge, and we examined their stated reasons for nonadherence.

RESULTS

Mean age was 66.8 years (SD = 8.9); 87.2% were women, and 84.2% were white. One-fourth of patients (24.8%) reported that they did not start their recommended pharmacotherapy. In the unadjusted analyses, the only factor significantly associated with nonadherence was osteoporosis knowledge, with those having better knowledge being less likely to take their medications (P < 0.05). The most common reasons for nonadherence were fear of adverse effects (53.3%), a dislike of taking medicine (25.3%), and the belief that the medication would not help their condition (16.7%).

CONCLUSION

One in 4 patients recommended for osteoporosis pharmacotherapy declined treatment because they feared potential adverse effects, did not like taking medicine, or believed that the medication would not help their condition. Improved patient counseling on the potential adverse effects of osteoporosis treatment and the risk-benefit ratio for these medications may increase adherence.

Utilization and cost of anti-osteoporosis therapy among US Medicare beneficiaries

There is a strong impetus to prevent and treat osteoporosis to prevent fractures. $990 million dollars was spent on anti-osteoporosis drugs in 2013. As we shift our focus on primary prevention of fractures, providers are encouraged to find the most cost-effective anti-osteoporosis therapy for patients.

PURPOSE

Osteoporosis is a major global problem with osteoporotic fractures posing a potentially avoidable burden on healthcare resources. We studied the utilization and cost of anti-osteoporotic therapy using the 2013 Medicare Part D data.

METHODS

Descriptive data were produced from Microsoft Excel and SPSS regarding the anti-osteoporotic drugs of interest.

RESULTS

In total, Medicare and its beneficiaries spent approximately $990 million on anti-osteoporotic therapy in 2013. Despite this cost, only one in two adults with osteoporosis aged 65 and older received a prescription for an anti-osteoporosis drug. $756 million (77 %) was attributable to brand name drugs which accounted for 2,459,931 claims (22 %). Generic dispensing rate varied from 57-86 % (mean 77 ± 6) across the different states in the USA. States that mandate substitution with generic equivalents had a higher generic dispensing rate compared to the states that permit generic substitution (92 vs. 90 %; p < 0.05). After adjusting for claim counts, we found that if the states that permit substitution with generic equivalents showed the same generic dispensing rate of 92 % as the states that mandate such substitution, there is a potential for savings of $7.5 million, approximately 9 % of the total expenditure in these states on oral bisphosphonates alone. Thirty-eight percent of the total prescriptions from orthopedic surgeons were for Forteo® or Prolia® compared to 12.5 % from specialists.

CONCLUSIONS

These findings highlight the need for ongoing training for physicians who engage in the care of patients with osteoporosis to manage the disease in a cost-effective manner.

Incidence and Predictors of Multiple Fractures Despite High Adherence to Oral Bisphosphonates: A Binational Population-Based Cohort Study

Oral bisphosphonates (BPs) are highly effective in preventing fractures and are recommended first-line therapies for patients with osteoporosis. We identified the incidence and predictors of oral BP treatment failure, defined as the incidence of two or more fractures while on treatment (≥2 FWOT) among users with high adherence. Fractures were considered from 6 months after treatment initiation and up to 6 months after discontinuation. Data from computerized records and pharmacy invoices were obtained from Sistema d'Informació per al Desenvolupament de l'Investigació en Atenció Primària (SIDIAP; Catalonia, Spain) and Danish Health Registries (Denmark) for all incident users of oral BPs in 2006-2007 and 2000-2001, respectively. Fine and Gray survival models using backward-stepwise selection (p-entry 0.049; p- exit 0.10) and accounting for the competing risk of therapy cessation were used to identify predictors of ≥2 FWOT among patients having persisted with treatment ≥6 months with overall medication possession ratio (MPR) ≥80%. Incidence of ≥2 FWOT was 2.4 (95% confidence interval [CI], 1.8 to 3.2) and 1.7 (95% CI, 1.2 to 2.2) per 1000 patient-years (PYs) within Catalonia and Denmark, respectively. Older age was predictive of ≥2 FWOT in both Catalonian and Danish cohorts: subhazard ratio (SHR) = 2.28 (95% CI, 1.11 to 4.68) and SHR = 2.61 (95% CI, 0.98 to 6.95), respectively, for 65 to <80 years; and SHR = 3.19 (95% CI, 1.33 to 7.69) and SHR = 4.88 (95% CI, 1.74 to 13.7), respectively, for ≥80 years. Further significant predictors of ≥2 FWOT identified within only one cohort were dementia, SHR = 4.46 (95% CI, 1.02 to 19.4) (SIDIAP); and history of recent or older fracture, SHR = 3.40 (95% CI, 1.50 to 7.68) and SHR = 2.08 (95% CI: 1.04-4.15), respectively (Denmark). Even among highly adherent users of oral BP therapy, a minority sustain multiple fractures while on treatment. Older age was predictive of increased risk within both study populations, as was history of recent/old fracture and dementia within one but not both populations. Additional and/or alternative strategies should be investigated for these patients.

Patterns of use for brand-name versus generic oral bisphosphonate drugs in Ontario over a 13-year period: a descriptive study

BACKGROUND

Bisphosphonates are the first-line therapy for the treatment of osteoporosis. In the province of Ontario, the Ontario Drug Benefit Program funds medications for patients aged 65 years and older. The Ontario Drug Benefit Program has a generic substitution policy that requires lower-cost generic drugs to be dispensed when they are available. However, there is controversy surrounding the efficacy and tolerability of generic bisphosphonates. The objective of this study was to describe patterns in the use of brand-name versus generic formulations when dispensing oral bisphosphonate over a 13-year period.

METHODS

We identified all osteoporotic preparations for alendronate and risedronate that were dispensed through the Ontario Drug Benefit Program from 2001 to 2014. We stratified our sample into community-dwelling residents and residents in long-term care facilities. The number of prescriptions dispensed per month were plotted to illustrate trends over time.

RESULTS

We found a rapid switch from brand-name to generic bisphosphonate equivalents immediately after the generic became available on the Ontario Drug Benefit formulary, with generics accounting for > 88% of dispensed drug within 2 months. We also observed a reduction in the number of generic drugs dispensed each time a new brand-name alternative (e.g., monthly risedronate, weekly alendronate plus vitamin D) was introduced to the formulary. The dispensing trends were similar in the community and long-term care settings.

INTERPRETATION

The Ontario Drug Benefit Program generic substitution policy resulted in rapid uptake of generic oral bisphosphonates among seniors in Ontario. However, there was a switch away from generic medications to new brand-name alternatives whenever they were introduced to the formulary. Therefore, some patients continued to use brand-name bisphosphonate despite the availability of generic options.

A systematic review of osteoporosis medication adherence and osteoporosis-related fracture costs in men

BACKGROUND AND OBJECTIVE

Male osteoporosis is an increasingly important public health concern. Although several medications are approved for the treatment of osteoporosis, medication non-adherence and the associated consequences are not well documented in male populations. Our objective was to identify and summarize the current knowledge related to osteoporotic medication adherence, the potential implications of non-adherence to the medication, and the cost of osteoporosis-related fractures and health-resource utilization in men.

METHODS

Two separate systematic searches were conducted concurrently: one to identify literature reporting male-specific adherence to anti-osteoporotic medication and the clinical consequence of non-adherence in men, and the other to identify literature reporting the cost and resource burden of osteoporosis-related fractures in men. The PubMed, MEDLINE, EMBASE, and Cochrane databases were searched using a date range of 1 January 1998 to 30 June 2012, and citations were screened based on pre-defined criteria.

RESULTS

The percentage of males adherent to bisphosphonates [medication possession ratio (MPR) >0.8] over a 1-year period ranged from 32% to 64%. The data imply worse clinical outcomes with treatment non-adherence. Costs and resource use associated with osteoporosis-related fractures in men are high, with hip fractures generating the most cost.

CONCLUSIONS

One-third to two-thirds of men are not adherent to bisphosphonates. Non-adherence is associated with increased fracture risk. Estimates of direct and indirect osteoporosis-related fracture costs are also substantial in men, and may even be more costly than in women. More robust data would better inform disease management initiatives that could improve adherence to medication and outcomes in men with osteoporosis.

Differences in In Vitro Disintegration Time among Canadian Brand and Generic Bisphosphonates

The objective of this study was to compare the disintegration times among Canadian-marketed brand (alendronate 70 mg, alendronate 70 mg plus vitamin D 5600 IU, and risedronate 35 mg) and generic (Novo-alendronate 70 mg and Apo-alendronate 70 mg) once-weekly dosed bisphosphonates. All disintegration tests were performed with a Vanderkamp Disintegration Tester. Disintegration was deemed to have occurred when no residue of the tablet, except fragments of insoluble coating or capsule shell, was visible. Eighteen to 20 samples were tested for each bisphosphonate group. The mean (±standard deviation) disintegration times were significantly (P < 0.05) faster for Apo-alendronate (26 ± 5.6 seconds) and Novo-alendronate (13 ± 1.1 seconds) as compared to brand alendronate (147 ± 50.5 seconds), brand alendronate plus vitamin D (378 ± 60.5 seconds), or brand risedronate (101 ± 20.6 seconds). The significantly faster disintegration of the generic tablets as compared to the brand bisphosphonates may have concerning safety and effectiveness implications for patients administering these therapies.

Predictors of fracture while on treatment with oral bisphosphonates: a population-based cohort study

Although oral bisphosphonates (BPs) are highly effective in preventing fractures, some patients will fracture while on treatment. We identified predictors of such fractures in a population-based cohort of incident users of oral BPs. We screened the Sistema d'Informació per al Desenvolupament de l'Investigació en Atenció Primària (SIDIAP) database to identify new users of oral BPs in 2006-2007. SIDIAP includes pharmacy invoice data and primary care electronic medical records for a representative 5 million people in Catalonia (Spain). Exclusion criteria were the following: Paget disease; <40 years of age; and any antiosteoporosis treatment in the previous year. A priori defined risk factors included age, gender, body mass index, vitamin D deficiency, smoking, alcohol drinking, preexisting comorbidities, and medications. Fractures were considered if they appeared at least 6 months after treatment initiation. "Fractures while on treatment" were defined as those occurring among participants persisting for at least 6 months and with an overall high compliance (medication possession ratio ≥80%). Fine and Gray survival models accounting for competing risk with therapy discontinuation were fitted to identify key predictors. Only 7449 of 21,385 (34.8%) participants completed >6 months of therapy. Incidence of fracture while on treatment was 3.4/100 person-years (95% confidence interval [CI], 3.1-3.7). Predictors of these among patients persisting and adhering to treatment included: older age (subhazard ratio [SHR] for 60 to <80 years, 2.18 [95% CI, 1.70-2.80]; for ≥80 years, 2.5 [95% CI, 1.82-3.43]); previous fracture (1.75 [95% CI, 1.39-2.20] and 2.49 [95% CI, 1.98-3.13], in the last 6 months and longer, respectively); underweight, 2.11 (95% CI, 1.14-3.92); inflammatory arthritis, 1.46 (95% CI, 1.02-2.10); use of proton pump inhibitors (PPIs), 1.22 (95% CI, 1.02-1.46); and vitamin D deficiency, 2.69 (95% CI, 1.27-5.72). Even among high compliers, 3.4% of oral BP users will fracture every year. Older age, underweight, vitamin D deficiency, PPI use, previous fracture, and inflammatory arthritides increase risk. Monitoring strategies and/or alternative therapies should be considered for these patients.

A critical review of brand and generic alendronate for the treatment of osteoporosis

Objective

Compare in vitro and in vivo characteristics and clinical outcomes of brand and generic alendronate.

Research design and methods: Relevant search terms were input into Medline ("alendronate" AND "generic" up to August 5, 2013) and any abstracts deemed possibly relevant selected for full paper review and abstraction.

Results

Multicentre, randomized, placebo-controlled Phase III clinical trials of substantial size and duration have established the anti-fracture efficacy and safety of brand amino-bisphosphonates. For regulatory approval, generic versions of brand drugs need to demonstrate bioequivalence in young, healthy volunteers and have similar dissolution times. While the potency and amount of active drug within generic formulations must be identical to the brand, differences are permitted in the excipients. Significant differences in tablet disintegration time among different versions of generic and brand alendronate have been reported. Rapidly disintegrating alendronate pills may increase oesophageal bioadhesion and adverse event risk. Oesophageal-bound alendronate or slow disintegrating alendronate tablets may be made inert and ineffective by subsequently ingested food or drink. Investigations have reported a lower persistence to therapy with generic brands of alendronate as compared to brand bisphosphonates and patients switched from brand to generic alendronate have increased adverse event rates and losses in bone mineral density.

Conclusion

Numerous differences exist between brand and generic alendronate including: disintegration time, bioadhesion to the oesophagus, patient persistence to therapy, adverse event incidence, and maintenance of bone mineral density. Generic forms of alendronate warrant closer clinical study before they are ascribed the clinical effectiveness and tolerability of brand alendronate.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-2-550) contains supplementary material, which is available to authorized users.

Persistence with osteoporosis medication among newly-treated osteoporotic patients

Low persistence with osteoporosis medication is associated with higher fracture risk. Previous studies estimated that 1-year persistence with osteoporosis medication is low. Our aim was to study persistence with osteoporosis medication among patients with long-term follow-up (to 5 years). The InterAction Database (IADB) was used to analyze persistence of 8610 Dutch patients initiating osteoporosis drugs between 2003 and 2011. Drugs under study were alendronate, risedronate, ibandronate, etidronate, raloxifene and strontium ranelate. Cumulative persistence rates were calculated after different time frames (3 months-5 years) using survival analysis. Multivariate Cox proportional hazard analyses were used to identify determinants of non-persistence. Furthermore, switching rates of persistent patients who initiated bisphosphonate therapy were analyzed. Persistence with osteoporosis therapy was 70.7 % (95 % CI, 69.7-71.7), 58.5 % (95 % CI, 57.4-59.6 %), 25.3 % (95 % CI, 24.1-26.5) after 6 months, 1 and 5 years, respectively. Determinants associated with higher risk to non-persistence within the first year were daily dosing regimen [HR, 1.76 (95 % CI, 1.46-2.14)], age <60 years [HR, 1.26 (95 % CI, 1.19-1.34)] and use of glucocorticoids [HR, 1.16 (95 % CI, 1.07-1.26)]. Monthly dosing schedule and use of generic brands of alendronate did not show a significant association with non-persistence. Approximately 4.0 % of patients initiating therapy with weekly alendronate or weekly risedronate switched therapy. Persistence with osteoporosis medication is low. Because low persistence is strongly associated with higher fracture risk, interventions to improve persistence are recommended. This study identified several patient groups in whom such interventions may be most relevant.

Bisphosphonates adherence for treatment of osteoporosis

BACKGROUND

Osteoporosis is a disease of bone metabolism in which bisphosphonates (BPS) are the most common medications used in its treatment, whose main objective is to reduce the risk of fractures. The aim of this study was to conduct a systematic review on BPs adherence for treatment of osteoporosis.

METHODS

Systematic review of articles on BPs adherence for treatment of osteoporosis, indexed on MEDLINE (via PubMed) databases, from inception of databases until January 2013. Search terms were "Adherence, Medication" (MeSH term), "Bisphosphonates" (MeSH term), and "Osteoporosis" (MeSH term).

RESULTS

Of the 78 identified studies, 27 met the eligibility criteria. Identified studies covered a wide range of aspects regarding adherence and associated factors, adherence and fracture, adherence and BPs dosage. The studies are mostly observational, conducted with women over 45 years old, showing low rates of adherence to treatment. Several factors may influence adherence: socio-economic and cultural, participation of physicians when guidance is given to the patient, the use of bone turnover markers, and use of generic drugs. The monthly dosage is associated with greater adherence compared to weekly dosage.

CONCLUSIONS

Considering the methodological differences between the studies, the results converge to show that adherence to treatment of osteoporosis with BPs is still inadequate. Further experimental studies are needed to evaluate the adherence and suggest new treatment options.

Cost-effective intervention thresholds against osteoporotic fractures based on FRAX® in Switzerland

FRAX-based cost-effective intervention thresholds in the Swiss setting were determined. Assuming a willingness to pay at 2× Gross Domestic Product per capita, an intervention aimed at reducing fracture risk in women and men with a 10-year probability for a major osteoporotic fracture at or above 15% is cost-effective.

INTRODUCTION

The fracture risk assessment algorithm FRAX® has been recently calibrated for Switzerland. The aim of the present analysis was to determine FRAX-based fracture probabilities at which intervention becomes cost-effective.

METHODS

A previously developed and validated state transition Markov cohort model was populated with Swiss epidemiological and cost input parameters. Cost-effective FRAX-based intervention thresholds (cost-effectiveness approach) and the cost-effectiveness of intervention with alendronate (original molecule) in subjects with a FRAX-based fracture risk equivalent to that of a woman with a prior fragility fracture and no other risk factor (translational approach) were calculated based on the Swiss FRAX model and assuming a willingness to pay of 2 times Gross Domestic Product per capita for one Quality-adjusted Life-Year.

RESULTS

In Swiss women and men aged 50 years and older, drug intervention aimed at decreasing fracture risk was cost-effective with a 10-year probability for a major osteoporotic fracture at or above 13.8% (range 10.8% to 15.0%) and 15.1% (range 9.9% to 19.9%), respectively. Age-dependent variations around these mean values were modest. Using the translational approach, treatment was cost-effective or cost-saving after the age 60 years in women and 55 in men who had previously sustained a fragility fracture. Using the latter approach leads to considerable underuse of the current potential for cost-effective interventions against fractures.

CONCLUSIONS

Using a FRAX-based intervention threshold of 15% for both women and men should permit cost-effective access to therapy to patients at high fracture probability based on clinical risk factors and thereby contribute to further reduce the growing burden of osteoporotic fractures in Switzerland.

Adherence with intravenous zoledronate and intravenous ibandronate in the United States Medicare population

OBJECTIVE

To evaluate adherence to drug therapy among new users of zoledronate and intravenous (IV) ibandronate among US Medicare enrollees.

METHODS

We used data from the Medicare 5% random sample to evaluate new users of IV zoledronate and IV ibandronate with continuous Part A and Part B fee-for-service coverage. The outcome was adherence as quantified by the proportion of days covered (PDC) measured continuously and dichotomously (≥ 80%). Followup time extended from 18-27 months for all individuals. Factors associated with low adherence to zoledronate were evaluated with logistic regression.

RESULTS

We identified 775 new users of zoledronate and 846 new users of IV ibandronate. For both drugs, 30-48% of the first infusions were given in an outpatient infusion center, not in a physician's office. The mean PDC for zoledronate users was 82%, which was greater than the mean PDC for the IV ibandronate users (58-62% depending on the time period; P < 0.0001). Approximately 30% of zoledronate users did not receive a second infusion. Factors associated with low adherence to zoledronate included older age and receipt of the first infusion in an outpatient infusion center rather than a physician's office.

CONCLUSION

Less frequently dosed IV bisphosphonates have not resolved the problem of suboptimal adherence with prescription osteoporosis medications. Interventions continue to be warranted to improve long-term adherence to osteoporosis treatments.

The association between automatic generic substitution and treatment persistence with oral bisphosphonates

Automatic generic substitution of alendronate products, used to reduce drug costs, and medication persistence was studied retrospectively between 2006 and 2009. During this period the number of, and the rate of substitution between, alendronate products increased while persistence decreased. Patient preferences should be considered when designing and evaluating generic policies.

INTRODUCTION

Automatic generic substitution (AGS) was implemented in Sweden in 2002. The objective of this study was to investigate the association between AGS and persistence with alendronate treatment of primary osteoporosis in Sweden.

METHODS

An open historical cohort of women and men (n = 36,433) was identified in the Swedish Prescribed Drug Register through filled prescriptions for alendronate or risedronate between 2005 and 2009. Co-morbidity data was extracted from the National Patient Register. The association between AGS and medication persistence was investigated using non-parametric and parametric survival analysis.

RESULTS

Between 2006 and 2009, the number of alendronate products increased from 15 to 25, the proportion of prescriptions constituting a substitution increased from 10.8% to 45.2%, and the proportion of patients persisting with alendronate treatment for 12 months fell from 66.9% to 51.7%. Patients starting alendronate treatment in 2006 had lower risk of stopping treatment compared with those starting in 2007 (HR 1.34, 95% CI 1.29-1.39), 2008 (HR 1.49, 95% CI 1.43-1.55), and 2009 (HR 1.50, 95% CI 1.40-1.60). No difference was observed in persistence with proprietary risedronate during the same period. Individuals who had their alendronate product substituted at the first prescription refill had significantly higher probability of discontinuation (HR 1.25, 95% CI 1.20-1.30).

CONCLUSION

AGS causes increased product substitution which appears to be associated with reduced treatment persistence. Poor health outcomes and associated costs due to forgone drug exposure should be taken into account in the design and evaluation of policies implemented to encourage utilisation of generic medicines.

Long-term impact of adherence to oral bisphosphonates on osteoporotic fracture incidence

Adherence to osteoporosis treatments is a critical parameter resulting in suboptimal effectiveness in real-life practice. The long-term effect of adherence on fracture risk has not been assessed. This was a retrospective study using provincial health insurance claims databases to assess the association between adherence to oral bisphosphonates (OBP) and incidence of osteoporotic fractures in all Ontario patients with osteoporosis between April 1996 and December 2009. Multivariate logistic regression models were used to assess the association between OBP adherence and fracture risk. Treatment duration was classified into 2-year intervals. Compliance was estimated with the medication possession ratio (MPR), and persistence was defined as the length of continuous therapy without a gap in refills >30 days. The study cohort was composed of 636,114 patients, among whom 36.1% were prescribed OBPs for 0 to 2 years, 19.7% for 2 to 4 years, 15.1% for 4 to 6 years, 12% for 6 to 8 years, 9.1% for 8 to 10 years, 6.1% for 10 to 12 years, and 1.9% for 12 to 14 years. Overall, the mean (SD) compliance for the cohort was 0.72 (0.30) with 53.5% of the patients having compliance >80% and 24.6% being persistent with treatment during the 14-year follow-up period. Significant associations between high adherence and reduced fracture risk over the entire 14-year period were observed; the overall odds ratio for categorical compliance (MPR >80% or MPR ≤80%), continuous compliance, and persistence were 0.909 (95% confidence interval [CI] 0.893-0.925), 0.918 (95% CI 0.893-0.944), and 0.804 (95% CI 0.787-0.821), respectively. In conclusion, adherence to OBP in osteoporosis management is suboptimal in a real-life setting. A significant positive association exists between poor adherence and increased risk of osteoporotic fractures, which becomes augmented with longer treatment duration.

A reappraisal of generic bisphosphonates in osteoporosis

The competitive price of generic bisphosphonates has had a marked effect on practice guidelines, but an increasing body of evidence suggests that they have more limited effectiveness than generally assumed.

INTRODUCTION

The purpose of this study is to review the impact of generic bisphosphonates on effectiveness in the treatment of osteoporosis.

METHODS

This study is a literature review.

RESULTS

A substantial body of evidence indicates that many generic formulations of alendronate are more poorly tolerated than the proprietary preparations which results in significantly poorer adherence and thus effectiveness. Poorer effectiveness may result from faster disintegration times of many generics that increase the likelihood of adherence of particulate matter to the oesophageal mucosa. Unfortunately, market authorisation, based on the bioequivalence of generics with a proprietary formulation, does not take into account the potential concerns about safety. The poor adherence of many generic products has implications for guideline development, cost-effectiveness and impact of treatment on the burden of disease.

CONCLUSIONS

The impact of generic bisphosphonates requires formal testing to re-evaluate their role in the management of osteoporosis.

A review of the cost effectiveness of bisphosphonates in the treatment of post-menopausal osteoporosis in Switzerland

The economic burden associated with osteoporosis is considerable. As such, cost-effectiveness analyses are important contributors to the diagnostic and therapeutic decision-making process. The aim of this study was to review the cost effectiveness of treating post-menopausal osteoporosis with bisphosphonates and identify the key factors that influence the cost effectiveness of such treatment in the Swiss setting. A systematic search of databases (MEDLINE, EMBASE and the Cochrane Library) was conducted to identify published literature on the cost effectiveness of bisphosphonates in post-menopausal osteoporosis in the Swiss setting. Outcomes were compared with similar studies in Western European countries. Three cost-effectiveness studies of bisphosphonates in this patient population were identified; all were from a healthcare payer perspective. Outcomes showed that, relative to no treatment, treatment with oral bisphosphonates was predicted to be cost saving for most women aged ≥70 years with osteoporosis or at least one risk factor for fracture, and cost effective for women aged ≥75 years without prior fracture when used as a component of a population-based screen-and-treat programme. Results were most sensitive to changes in fracture risk, cost of fractures, cost of treatment, nursing home admissions and adherence with treatment. Swiss results were generally comparable to those in other European settings. Assuming similar clinical efficacy, lowering treatment cost (through the use of price-reduced brand-name or generic drugs) and/or improving adherence should both contribute to further improving the cost effectiveness of bisphosphonates in women with post-menopausal osteoporosis. Published evidence indicates that bisphosphonates are estimated to be similarly cost effective or cost saving in most treatment scenarios of post-menopausal osteoporosis in Switzerland and in neighbouring European countries.

Cost effectiveness of denosumab compared with oral bisphosphonates in the treatment of post-menopausal osteoporotic women in Belgium

BACKGROUND

Denosumab has recently been shown to be well tolerated, to increase bone mineral density (BMD) and to significantly reduce the risk of hip, vertebral and non-vertebral fractures in the FREEDOM (Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months) trial. It is becoming increasingly important to evaluate not only the therapeutic value of a new drug but also the cost effectiveness compared with the most relevant treatment alternatives.

OBJECTIVE

The objective of this study was to estimate the cost effectiveness of denosumab compared with oral bisphosphonates (branded and generic drugs) in the treatment of post-menopausal osteoporotic women in Belgium.

METHODS

Cost effectiveness of 3 years of treatment with denosumab was compared with branded risedronate and branded and generic alendronate using an updated version of a previously validated Markov microsimulation model. The model was populated with relevant cost, adherence and epidemiological data for Belgium from a payer perspective and the results were presented as costs per QALY gained (&U20AC;, year 2009 values). Analyses were performed in populations (aged ≥60 years) in which osteoporosis medications are currently reimbursed in many European countries, i.e. those with BMD T-score of -2.5 or less or prevalent vertebral fracture. Patients receiving denosumab were assumed to have a 46% lower risk of discontinuation than those receiving oral bisphosphonates, and the effect of denosumab after treatment cessation was assumed to decline linearly to zero over a maximum of 1 year.

RESULTS

Denosumab was cost effective compared with all other therapies, assuming a willingness to pay of &U20AC;40 000 per QALY gained. In particular, denosumab was found to be cost effective compared with branded alendronate and risedronate at a threshold value of &U20AC;30 000 per QALY and denosumab was dominant (i.e. lower cost and greater effectiveness) compared with risedronate from the age of 70 years in women with a T-score of -2.5 or less and no prior fractures. The cost effectiveness of denosumab compared with generic alendronate was estimated at &U20AC;38 514, &U20AC;22 220 and &U20AC;27 862 per QALY for women aged 60, 70 and 80 years, respectively, with T-scores of -2.5 or less. The equivalent values were &U20AC;37 167, &U20AC;19 718 and &U20AC;19 638 per QALY for women with prevalent vertebral fractures.

CONCLUSION

This study suggests, on the basis of currently available data, that denosumab is a cost-effective strategy compared with oral bisphosphonates (including generic alendronate) for the treatment of post-menopausal osteoporotic women, aged ≥60 years in Belgium. Denosumab therefore appears to have the potential to become a first-line treatment for post-menopausal women with osteoporosis. However, further studies would be required to evaluate the long-term safety and adherence of denosumab in real-world clinical practice as well as head-to-head effectiveness compared with oral bisphosphonates.

Safety of long-term bisphosphonate therapy for the management of osteoporosis

Drugs in the bisphosphonate class are the most commonly prescribed therapeutic agents for the treatment of osteoporosis. Prospective, randomized, placebo-controlled clinical trials have demonstrated efficacy in reducing fracture risk, with favourable safety profiles, in women with postmenopausal osteoporosis. However, long-term use in clinical practice has been associated with reports of undesirable events not previously recognized. These have included gastrointestinal intolerance, osteonecrosis of the jaw, atypical femur fractures, oesophageal cancer, atrial fibrillation and chronic musculoskeletal pain. Physicians must be alert to newly recognized safety concerns, understand the level of evidence supporting them and be able to effectively communicate the balance of expected benefit and potential risk to patients. Usually, post-marketing adverse events are first presented as case reports or observational studies with variable levels of supporting evidence for plausibility, pathophysiology and causality. Widespread coverage in the news media, which can be alarming to patients and their physicians, may not present a balanced view of the proven benefits, the uncertain risks of therapy and the relative magnitude of these events. There may be confusion about the risks associated with bisphosphonate use for the treatment of osteoporosis versus treatment of other conditions, such as cancer, which typically involves a very different patient population and different doses or frequency of drug administration. Often reports of possible adverse events do not provide information on the number of patients exposed to the drug in proportion to the reported adverse event, or do not describe the incidence of the adverse event in a comparator population not exposed to the drug. Gastrointestinal intolerance with oral bisphosphonates, and hypocalcaemia, acute phase reactions and renal toxicity with intravenous bisphosphonates are characterized by biological plausibility and demonstration of causality. Safety concerns with uncertain biological plausibility and unproven causality include osteonecrosis of the jaw, atypical femur fractures, oesophageal cancer and ocular inflammation. Suspected concerns that are unlikely to be causally related include atrial fibrillation and hepatotoxicity. When making the decision to use a bisphosphonate for the treatment of osteoporosis, the balance between benefit and potential risks according to clinical circumstances of each patient should be considered.

Pharmacology of bisphosphonates

Four decades of preclinical and clinical research of the pharmacology of bisphosphonates have generated data and concepts that have considerably improved their clinical use. However, despite this progress several pharmacological aspects relevant to bisphosphonate action on bone are still incompletely understood. This is mainly due to the complex, unique pharmacological properties of bisphosphonates. We review here the pharmacokinetic and pharmacodynamic data of bisphosphonates that are relevant for their clinical application and for the potential choice of a given compound, focusing on uncertainties that still exist.

Bisphosphonate use and risk of post-operative fracture among patients undergoing a total knee replacement for knee osteoarthritis: a propensity score analysis

SUMMARY

We have shown that patients with osteoarthritis are at increased risk of fracture after total knee replacement (TKR). We conducted a population-based cohort study to assess the effect of bisphosphonate use on their post-surgery fracture risk. Cox regression adjusted by propensity score suggested a 50-55% reduction in risk of fracture post-surgery.

INTRODUCTION

Patients with osteoarthritis have a higher bone mass but similar or higher risk of fracture. We recently demonstrated that patients have an elevated fracture risk after TKR, but it is unknown if bisphosphonate therapy in this patient group would reduce fracture risk. We aimed to assess the effect of bisphosphonate prescription to patients undergoing a TKR, on their risk of fracture after surgery.

METHODS

From the General Practice Research Database, all patients ≥ 40 years old, who received a TKR from 1986 to 2006 for knee osteoarthritis were eligible. We identified bisphosphonate use (BPU) as the main exposure. Propensity scores (equivalent to the estimated conditional probability of being treated given the individual's covariates) were calculated using logistic regression and used to reduce observed confounding. We fitted Cox models to study the effect of BPU on post-surgery fracture occurrence. Analyses were stratified by history of previous fracture: no fracture, osteoporotic fracture (hip, wrist, humerus, spine), and other fractures.

RESULTS

The hazard ratio (HR) associated with BPU in non-previously fractured patients was 0.50 (95% confidence interval, 0.37-0.68; propensity-adjusted model), and 0.48 (0.35-0.65; matched analysis). In subjects with osteoporotic and with other previous fracture, BPU was associated with a propensity-adjusted HR of 0.46 (0.30 to 0.71) and 0.47 (0.26-0.85), respectively, and with a propensity-matched HR of 0.45 (0.29 to 0.70) and 0.45 (0.25-0.82).

CONCLUSION

Our results suggest that BPU in primary prevention could reduce post-operative risk of fracture by 50% and by 55% in secondary prevention.

Adherence and profile of non-persistence in patients treated for osteoporosis--a large-scale, long-term retrospective study in The Netherlands

SUMMARY

We analyzed 12-month compliance for all ten oral osteoporosis drugs in the Netherlands by medication possession ratio (MPR ≥ 80%) in 105,506 patients, and persistence in 8,626 starters indicated high MPR (91%), low persistence (43%), and no restart in 78% of the stoppers after 18 months.

INTRODUCTION

We studied compliance and persistence for all available oral osteoporosis medications on a national scale in the Netherlands.

METHODS

We analyzed the IMS Health's longitudinal prescription database, which represents 73% of all pharmacies in the Netherlands. Twelve-month compliance was measured by medication possession ratio (MPR) in a cross-sectional cohort of 105,506 patients who received at least three prescriptions. Twelve-month persistence (no gap in refills for >6 months) was measured in all 8,626 consecutive patients starting therapy, with a further follow-up in non-persistent patients during an additional 18 months for evaluation of switching, restart, or definitive stopping oral medication. Multivariate logistic regression analysis was used to analyze the odds ratios (ORs) with 95% confidence intervals (CI) of characteristics of non-persistence.

RESULTS

MPR of ≥80% was found in 91% of patients. Persistence was 43% (range, 29-52%). Persistence was related to age >60 years (ORs, 1.41 to 1.64), pharmacy outside very dense urban area (ORs, 1.39 to 1.44), additional use of calcium and/or vitamin D supplementation (OR, 1.26 and CI, 1.13, 1.39) and use of glucocorticoids (OR, 0.65 and CI, 0.59, 0.72) or cardiovascular medication (OR, 0.88 and CI, 0.79, 0.97). Of non-persistent patients, 22% restarted within 18 months with oral osteoporosis drugs.

CONCLUSIONS

One-year compliance for all available oral osteoporosis medications was high, but 1-year persistence was low. Most stoppers did not restart or switch during an additional 18-month follow-up. These data indicate a major failure to adequately treat patients at high risk for fractures in daily practice.

The cost effectiveness of zoledronic acid 5 mg for the management of postmenopausal osteoporosis in women with prior fractures: evidence from Finland, Norway and the Netherlands

OBJECTIVE

This study was conducted to assess the cost effectiveness of zoledronic acid 5 mg as a first-line treatment for the secondary prevention of fragility fractures in women with postmenopausal osteoporosis in Finland, Norway and the Netherlands.

METHODS

A discrete-event, individual-patient computer-simulation model was used to compare the cost effectiveness of zoledronic acid with that of basic treatment (calcium and vitamin D) and commonly prescribed bisphosphonates in postmenopausal women aged 50-80 years who have experienced one previous fracture and have a bone mineral density T-score of -2.5.

RESULTS

The cost per quality-adjusted life-year (QALY) gained with zoledronic acid compared with basic treatment ranged from being cost saving in all age groups in Norway, to costing approximately €19,000 in Finland and €22,300 in the Netherlands. Compared with the other branded bisphosphonates, zoledronic acid was cost saving in many scenarios, including all age groups in Finland. In Norway, zoledronic acid dominated branded risedronate and ibandronate in all age groups and dominated or had incremental cost-effectiveness ratios (ICERs) of up to NOK83,954 per QALY gained compared with branded alendronate. In the Netherlands, zoledronic acid dominated branded intravenous ibandronate in all age groups; compared with branded risedronate and oral ibandronate, zoledronic acid dominated or had ICERs of up to €4832 per QALY gained; compared with branded alendronate, it had ICERs of up to €48,383 per QALY gained. In all three countries, zoledronic acid may be cost effective compared with generic alendronate when patient compliance with drug therapy is taken into account. Sensitivity analyses showed that the model was robust to changes in key values. The main model limitations were the lack of real-life compliance and persistence data, and lack of country-specific data for some parameters.

CONCLUSIONS

Using local or commonly used thresholds, this analysis suggests that zoledronic acid would be a cost-effective first-line option compared with other branded bisphosphonates and, in some scenarios, compared with generic alendronate, for the secondary prevention of fractures in women with postmenopausal osteoporosis in Finland, Norway and the Netherlands.

Risk of upper gastrointestinal tract events in risedronate users switched to alendronate

Upper gastrointestinal (GI) side effects are a known complication of therapy with oral aminobisphosphonates, but it is currently unclear if bisphosphonate type or formulation influences the risk of developing side effects. Here, we performed a retrospective cohort study to determine if patients who switched from weekly risedronate to weekly alendronate had an increased risk of upper GI side events. The study utilized The Health Improvement Network (THIN) database, which contained anonymous medical records from 390 general practices in the United Kingdom. The study was performed following the introduction of generic alendronate preparations, by which point 94% of alendronate prescriptions were for the generic formulation. We identified 3,446 patients who had been stabilized on risedronate 35 mg/week, of whom 530 were switched to alendronate 70 mg/week. The risk of developing a GI adverse event was higher in patients who switched to alendronate compared with those who remained on risedronate (hazard ratio [HR] = 1.85, 95% confidence interval [CI] 1.26-2.72). The risk was even greater in the subgroup of patients with a history of upper GI events (HR = 3.18, 95% CI 2.79-3.63) but was also observed in patients with no history of GI events (HR = 1.76, 95% CI 1.15-2.69). We conclude that switching patients who are stabilized on risedronate to alendronate is associated with an increased risk of GI adverse effects. This could lead to reduced compliance and reduced therapeutic effectiveness, which might offset the cost savings of using the generic formulation.

Adverse events, bone mineral density and discontinuation associated with generic alendronate among postmenopausal women previously tolerant of brand alendronate: a retrospective cohort study

Background

A rise in gastrointestinal (GI) adverse events (AEs) and a decline in bone mineral density (BMD) was observed in patients previously tolerant to brand alendronate shortly after generic versions were introduced in July 2005 to the Canadian market. The objective of our study was to quantify changes in AE rates and BMD scores, as well as associated alendronate discontinuation among patients before and after switch from brand to generic alendronate.

Methods

A chart review of postmenopausal women 50 years of age and older between 2003 and 2007 was conducted in two specialized tertiary care referral centers. Patients on alendronate both before and after July 2005 were included. The change in the number of AEs, changes in BMD and associated alendronate discontinuation was compared before and after the switch from brand to generic alendronate.

Results

301 women with an average age of 67.6 years (standard deviation (SD) = 9.5) had a total of 47 AEs between July 2003 and December 2007 that resulted in discontinuation of the medication. There was a significant increase in the rate of AEs per patient-months-at-risk from 0.0001 before to 0.0044 after October 2005 (p < 0.001). The most common AEs were GI in nature (stomach pain, GI upset, nausea, and reflux). In addition, 23 patients discontinued alendronate due to BMD reduction after January 2006. In these patients, BMD scores were significantly reduced from their prior BMD measures (change of -0.0534, p < 0.001 for spine BMD and change of -0.0338, p = 0.01 for femur BMD). Among patients who discontinued due to BMD reduction, BMD was stable in the period prior to January 2006 (change of -0.0066, p = 0.5 for spine BMD and change of 0.0011, p = 0.9 for femur BMD); however, testing for reduction after January 2006 in BMD measures (one-sided T-test) revealed there was a significant reduction in BMD scores for both anatomic sites (change of -0.0321, p = .005 for spine, change of -0.0205, p = 0.05 for femur).

Conclusions

Patients who were previously stable on doses of brand alendronate experienced an increase in AEs causing discontinuation after introduction of automatic substitution to generic alendronate. In addition, reductions in BMD were observed in some patients who had stable BMDs before January 2006. Given the substantial increase in AEs, generic alendronate may not be as well tolerated as brand alendronate.