Analysis of the Comparative Effectiveness of 3 Oral Bisphosphonates in a Large Managed Care Organization: Adherence, Fracture Rates, and All-Cause Cost

Abstract

• Randomized, controlled trials (RCTs) of oral bisphosphonates have shown statistically significant reductions in fracture rates versus placebo, but whereas alendronate and risedronate have shown reductions in vertebral and nonvertebral fractures, ibandronate has been shown to reduce vertebral fractures only. Comparison of fracture rates among the bisphosphonates is difficult due to the lack of head-to-head RCTs designed to compare this outcome.• Several observational studies regarding osteoporosis therapy have been published. A recent analysis by Halpern et al. (2011) showed that low adherence (medication possession ratio [MPR] < 80%) was associated with 37% higher fracture risks and 12% higher all-cause medical costs. However, there is a lack of comparative effectiveness data for adherence, fracture rates, and total cost of care among the 3 commonly used oral bisphosphonates (alendronate, risedronate, and ibandronate) for a period longer than 12-18 months. What is already known about this subject

Analysis of osteoporosis treatment patterns with bisphosphonates and outcomes among postmenopausal veterans

“…Briesacher and colleagues similarly did not find a significant effect on fracture risk in patients who switched from once weekly to once monthly bisphosphonates [21], and others found that switching bisphosphonates improved persistence overall, which would be expected to reduce fracture risk [7,19,20]. Our data also suggest that medication-taking patterns, even discontinuation, do not significantly impact fracture risk, which does not correspond to what others have found [8,[12][13][14][15][16][17][18]58]. We can propose reasons for our inability to detect a relationship between bisphosphonate discontinuations and fracture risk.…”

“…In observational studies, the proportions of patients that persisted with therapy for 1 year are low for United States (US) cohorts (21.0-56.7%) and non-US cohorts (21.9-74.8%) [2][3][4][5][6][7][8][9][10][11]. Some studies have reported an association between low adherence or persistence and fracture outcomes or healthcare costs (i.e., higher fracture rates or higher costs in patients with lower adherence) [8,[12][13][14][15][16][17][18]. However, the effect of changing medications on osteoporosis health outcomes has not been well characterized.…”

“…However, the effect of changing medications on osteoporosis health outcomes has not been well characterized. Several studies demonstrate improved persistence or adherence following a treatment switch [7,19,20], with only one to the contrary [16]. We are aware of one study using a small regional cohort that examined the effect of medication switching on fracture risk.…”

“…However, no studies adjusted for baseline BMD in an effort to isolate the independent effect of adherence on outcomes in patients across a range of osteoporosis severity. This is, perhaps, because most studies that use administrative claims datasets typically do not contain clinical data [11,[14][15][16][17]20]. However, even studies conducted in datasets containing some clinical data [8,13] still lacked the ability to capture BMD in structured data, making adjustment for baseline disease severity challenging.…”

High rate of non-treatment among osteoporotic women enrolled in a US Medicare plan

“…Subjects were required to either have a medical claim with an OP diagnosis (ICD-9-CM 733.0x) or an OP-related fracture as evidenced by both an ICD-9-CM diagnosis code and CPT code [29][30][31] (see the supplementary Appendix for codes) between 1 January 2007 and 31 December 2011. Additionally, subjects were required to be continuously enrolled in any tracked health plan for all of 2011 and 2012.…”