Impact of noncompliance with alendronate and risedronate on the incidence of nonvertebral osteoporotic fractures in elderly women

Abstract

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Compliance with alendronate and risedronate is suboptimal.• Few studies have specifically evaluated the impact of noncompliance with alendronate or risedronate on the incidence of osteoporotic fractures in community-dwelling elderly women. WHAT THIS STUDY ADDS• Among community-dwelling elderly women, noncompliance [defined as medication possession ratio (MPR) < 80%] with alendronate or risedronate was associated with a 27% increased risk of nonvertebral fracture [rate ratio (RR) 1.27, 95% confidence interval (CI) 1.12, 1.44].• This study is the first to assess the impact of noncompliance with bisphosphonates in a subgroup of women aged > 80 years.• Among women aged > 80 years, MPR < 80% was associated with a 48% greater risk of sustaining a nonvertebral fracture (RR 1.48, 95% CI 1.19, 1.85), compared with women with a MPR Ն 80%. AIMSTo evaluate the association between noncompliance with alendronate and risedronate and the risk of nonvertebral osteoporotic fracture in community-dwelling elderly women. METHODSA nested case-control study was conducted using the Quebec administrative health databases. To be included in the cohort, women needed to be aged Ն 68 years and to have initiated treatment with alendronate or risedronate between 1 January 2002 and 31 March 2005. Cases consisted of all women with an incident nonvertebral osteoporotic fracture occurring Ն 1 year after initiation of therapy. Each case was matched with up to 20 controls using incidence density sampling, according to age (Ϯ 1 year) and follow-up duration. A woman was noncompliant if she had a medication possession ratio (MPR) <80% for total follow-up duration. Rate ratios (RR) for fracture were estimated through conditional logistic regression analysis, adjusting for potential confounders. RESULTSAmong the 30 259 women included in the cohort, 1036 nonvertebral fracture cases were identified and were matched to 20 069 controls. Compared with women with a MPR Ն 80%, those with a MPR < 80% had a greater risk of nonvertebral fracture [adjusted RR 1.27, 95% confidence interval (CI) 1.12, 1.44]. Considering hip fracture only, the multivariate model yielded similar results, (adjusted RR 1.28, 95% CI 1.02, 1.61). CONCLUSIONSAmong community-dwelling elderly women, noncompliance with alendronate or risedronate is associated with an increased risk of nonvertebral fracture.

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

“…Persistent patients had an overall adjusted fracture risk reduction of 20% with relative risk estimates ranging from 0.867 to 0.520 depending on the duration of treatment. The meta-analysis of Imaz and colleagues (41) reported a relative risk for fractures of 1.46 (95% CI 1.34-1.60) for poorly versus highly compliant patients; Blouin and colleagues (42) reported an adjusted relative risk of approximately 1.20 (95% CI 1.04-1.40) for women with follow-up <850 days and 1.48 (95% CI 1.15-1.91) for women with Measured to the time of first fracture. A decrease in the odds ratio is observed with longer treatment duration, corresponding to a risk reduction range between 13% and 54%.…”

Bisphosphonates and osteoporotic fractures: a cross-design synthesis of results among compliant/persistent postmenopausal women in clinical practice versus randomized controlled trials

“…In one included database study, only 15% of patients received calcium and 7% vitamin D [27]. In another, compliance with calcium and vitamin D supplementation was poor, as evidenced by MPR <80% in 60% of cases [32]. Results of a third included study were adjusted for calcium and vitamin D supplementation [34].…”

“…In only four of the 11 included database studies was there a documented period of prior bisphosphonate treatment before counting of fractures commenced. A 3-month prior treatment period was specified in one study [31], 6 months in a second [7], and 12 months in two others [28,32].…”

Comparison of direct health care costs related to the pharmacological treatment of osteoporosis and to the management of osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate: a population-based study

“…Women with MPR< 80% incurred significantly higher physician care costs and Table 2 Results from the multiple logistic regressions used to predict the probability of using physician care and the probability of being hospitalized (first part of the two-part models) Risk factor for falls = history of prior accidental fall (ICD-9 [4,6]. However, physician care and hospital care costs increases among noncompliant women were not sufficient to offset higher drug costs among compliant women.…”

“…However, lack of compliance with these agents has been reported in several observational studies [2,3]. Noncompliance with alendronate and risedronate has been associated with an increased risk of osteoporotic fractures [4][5][6]. However, how this higher incidence of fractures affects osteoporosis-related direct health care costs is unknown.…”