Elsevier

Maturitas

Volume 48, Issue 3, 15 July 2004, Pages 271-287
Maturitas

Compliance with drug therapies for the treatment and prevention of osteoporosis

https://doi.org/10.1016/j.maturitas.2004.02.005Get rights and content

Abstract

Objectives: This study used paid claims data from real-world treatment settings to investigate the impact of hormone replacement therapy (HRT), bisphosphonate and raloxifene on patients with a recorded diagnosis of osteoporosis. Methods: Data from a large health insurer were used to identify 58,109 osteoporosis patients who initiated drug therapy for osteoporosis. Multivariate statistical models were developed for duration of therapy, compliance at 1 year, time to discontinuation or a change in therapy, health care costs and risk of fracture over 1 year. Results: One-year compliance rates were below 25% for all osteoporosis therapies. The mean unadjusted duration of continuous therapy was 221 days for raloxifene, 245 days for bisphosphonate, 262 for estrogen-only and 292 days for estrogen plus progestin. Raloxifene patients were consistently less compliant than estrogen-only patients after adjusting for differences in patient characteristics. Estrogen plus progestin patients were generally more compliant while bisphosphonate did not differentiate from estrogen-only. Compliance reduced the risk of hip fracture (o.r.=0.382, P<0.01) and vertebral fracture (o.r.=0.601, P<0.05). Compliant patients used fewer physicians services (−US$ 56, P<0.0001), hospital outpatient services (−US$ 38, P<0.05) and hospital care (−US$ 155, P<0.01). Bisphosphonate patients were twice as likely as estrogen-only patients to experience vertebral, Colles and other fractures and experienced higher health care costs (+US$ 420, P<0.01). The effectiveness of both raloxifene and bisphosphonate medications relative to estrogen-only improved significantly with the age of the patient. Conclusions: Compliance with drug therapies for osteoporosis over 1 year is poor leaving patients at risk for fractures and higher health care costs.

Section snippets

Background

Osteoporosis is a disease characterized by low bone mass density and micro-architectural deterioration of bone that increases the risk of bone fracture resulting in pain and deformity. Osteoporosis is considered a significant public health concern that will be magnified in the future as the population ages in the developed world. The National Osteoporosis Foundation (NOF) [1] estimates that low bone density affects about 44 million men and women in the US based on 2000 census data. This

Objectives

This study is designed to investigate patient compliance with drug therapies use to prevent and treat osteoporosis in real-world treatment settings, and to estimate the cost-consequences associated with non-compliance. Particular attention will be paid to comparing the patient outcomes achieved using estrogen-only, estrogen plus progestin, raloxifene or bisphosphonate. This study is particularly important on three fronts. First, the cost-effectiveness of alternative drug therapies to treat

Data

Data for this analysis were derived from the historical paid claims files for a large health insurance company located in California. Paid claims from the period January 1, 1998 to August 30, 2001 were available for inclusion in the analysis. These data included claims for prescription drugs, hospitalizations, physicians’ services, home health care, laboratory tests, emergency room visits, physical therapy and durable medical equipment. Patients were covered under a variety of insurance plans

Baseline characteristics

Table 2 presents data for the baseline demographic characteristics of patients by initial drug therapy. As expected, there are statistically significant and important differences across the four treatment groups under study. Based on this dataset, HRT is the dominant therapy among osteoporosis patients (91.0%). Only 6.4% of the patients used bisphosphonate; and 2.6% used raloxifene. Patients initiating hormone replacement therapy are younger than patients bisphosphonate or raloxifene and more

Discussion

Retrospective database analyses using paid claims data present an array of advantages and limitations relative to randomized clinical trials. First, clinicians require better data on how well alternative treatment options perform in unrestricted, real-world clinical settings. Compliance data from well controlled clinical trials does not correspond well to real-world practice as clinical trials are typically designed to minimize subject drop-out. It is also difficult to adequately measure health

Limitaitons

While great care has been taken to adjust estimated results for the baseline clinical characteristics of the patient population, other unobserved factors may exist that are correlated with the patient outcome measures studied here. Of particular concern is the lack of data for height, weight and bone density that are likely to be correlated with both patient outcomes and the selection of an initial therapy. Moreover, this analysis considers only the initial osteoporosis drug therapy used by the

Conclusions

Taken as a whole, patients who achieve 1 year of uninterrupted drug therapy for osteoporosis achieve better patient outcomes than patients who terminate or interrupt therapy during the first year. Unfortunately, less than 25% of patients achieve in excess of 1 year without breaking therapy and approximately 30% of patients switch therapies. This is a mixed blessing. The Women’s Health Initiative study [21] found that the long-term use of estrogen and progestin combination therapy (average 5.2

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