Elsevier

Bone

Volume 38, Issue 6, June 2006, Pages 922-928
Bone

Assessment of compliance with osteoporosis treatment and its consequences in a managed care population

https://doi.org/10.1016/j.bone.2005.10.022Get rights and content

Abstract

Objective:

To evaluate non-compliance with osteoporosis medications as well as its implications for health and economic outcomes in actual practice.

Study design:

Data on demographics, prescription drug dispensing, physician services and hospitalizations were obtained from a US managed care database for women with osteoporosis who were dispensed an osteoporosis medication between 1997 and 2002.

Methods:

Each subject's pattern of osteoporosis medication use was reconstructed using dispensing records. Subjects were considered compliant over a given period if their medication possession ratio (MPR) was ≥80% and gradients of compliance (<50% poor, 50–80% medium, 80–90% good, >90% excellent) were also examined. Using proportional hazards, the association between compliance over time and fracture rates was examined; Poisson regression was used for hospitalization and log-linear regression for medical costs.

Results:

38,120 women with osteoporosis were identified with a mean age of 66 years and an average follow-up of 1.7 years. Three quarters of them had an MPR below 80% when their entire follow-up was considered. Low compliance was associated with a 17% (95% CI 9–25%) increase in the fracture rate, adjusting for other known risk factors. Controlling for the specific drug regimen did not alter the association. Low compliance was also associated with a 37% (95% CI 32–43%) increase in the risk of all-cause hospitalization; and average monthly costs for all medical services combined were higher: $600 vs. $340 (P < 0.0001). Similar associations were observed when using the gradients of compliance.

Conclusions:

The desired goal of keeping patients with osteoporosis on chronic treatment is not being achieved adequately in actual practice and the potential social and economic implications of this behavior are substantial. Until compliance is improved, society will continue to fail in meeting an important public health goal.

Introduction

Osteoporosis is a condition characterized by low bone mass and deterioration of bone microarchitecture leading to increased susceptibility to fracture and consequent painful morbidity. Osteoporosis poses a major public health threat: in the United States today, 10 million individuals—eight million of whom are women—are estimated to already have the disease and almost 34 million more are estimated to already have lower bone mass, placing them at increased risk of osteoporosis and related fractures. Osteoporosis is responsible for more than 1.5 million fractures annually, predominantly of the hip, spine and wrist. The estimated national direct expenditures for osteoporotic and associated fractures were $17 billion in 2001 and the cost is rising [1].

Osteoporosis has taken an enormous toll among post-menopausal women. A 50-year-old woman in the United States has a 40% lifetime risk of an osteoporotic fracture. One in three women older than 80 years will sustain a hip fracture at some point, and 15 to 20% of them will die as a consequence [2].

Although there is no cure for osteoporosis, a broad range of therapies have been approved by the Food and Drug Administration for postmenopausal women to prevent or treat osteoporosis: from over-the-counter medications such as calcium and vitamin D, to estrogen therapy, and newer medications such as antiresorptive agents (i.e., bisphosphonates and selective estrogen-receptor modulators) and anabolic therapy [3], [4]. The clinical efficacy of these therapies has been demonstrated in terms of both an increase in bone density and a reduction in fractures. The efficacy found in clinical trials may not be replicated in actual practice, partly because of lack of compliance with the treatment regimen [5].

It has been suggested in the literature that about 50% of patients fail to take their medications as prescribed; either unintentionally because of forgetfulness or misunderstanding of instructions, or intentionally. Indeed, particularly for patients with chronic disorders requiring long-term therapy, the negative aspects of medication compliance (e.g., minor side-effects, being reminded of their illness or condition) often seem to outweigh the benefits [6].

In a previous analysis using the health services databases of Saskatchewan, Canada, we established that compliance with osteoporosis medications is poor and associated with a higher risk of fracture [7]. Here, we expand on that study in several ways. The extent of poor compliance with prescribed osteoporotic treatment and the association between compliance and loss of protection against fracture risk are examined in a US managed care population covered under various private and public benefit plans, instead of a Canadian population cared for in a publicly funded system. The study includes a greater number of subjects and covers a more recent time window during which new drugs or newer formulations of existing drugs were introduced. Finally, the potential economic implications of poor compliance are explored as well.

Section snippets

Sample and data selection

The data used in these analyses were obtained from the managed care database of Protocare Sciences, which comprises claims and eligibility records for over ten million lives covered under various public or private benefit plans in the United States.1 The plans cover a wide geographic distribution with

Study population

Data were obtained on 38,120 women who had an osteoporosis diagnosis between January 1997 and June 2002 followed by a prescription for an osteoporosis medication. Table 1 summarizes the characteristics of the members of the cohort. The average age of the women was 66 years.4 Enrollment was slightly higher during 2000–01 coinciding with the introduction of three new drugs (alendronate

Discussion

We studied a managed care cohort of 38,120 women with a diagnosis of osteoporosis who were dispensed osteoporotic medication between January 1997 and June 2002. Compliance with osteoporotic treatment was shown to be very low in actual practice: a rapid decline is observed during the first 2 years, after which the compliance level becomes more stable, hovering around 60%. Low compliance was associated with a higher risk of fractures regardless of other known and important risk factors such as

Acknowledgments

Source of Funding: This work was supported in part by a grant from Novartis Pharma AG. Novartis collaborated in helping set the specifications for the study but had no role in methodologic decisions nor interpretation of results. They were also allowed to review and comment on this manuscript but were explicitly forbidden from exerting any editorial control.

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