Psychometric properties of the Osteoporosis-specific Morisky Medication Adherence Scale in postmenopausal women with osteoporosis newly treated with bisphosphonates.

BACKGROUND: Poor adherence to oral osteoporosis medications is common. Strategies for improving adherence begin with identification of the problem. The 8-item Morisky Medication Adherence Scale for self-reported adherence to antihypertensive medications was modified for assessing adherence to oral osteoporosis medications. An evaluation of the measurement properties of the Osteoporosis-Specific Morisky Medication Adherence Scale (OS-MMAS) was needed. OBJECTIVE: To examine the psychometric properties of the OS-MMAS in women with postmenopausal osteoporosis. METHODS: Five hundred women aged 55 years and older with osteoporosis who were newly prescribed daily or weekly oral bisphosphonates between May 15, 2010, and August 15, 2010, were randomly selected from Kaiser Permanente Southern California, a large integrated health care delivery system, and mailed a self-administered survey that included the 8-item OS-MMAS, Self-Efficacy for Appropriate Medication Use Scale (SEAMS), Beliefs about Medicines Questionnaire (BMQ), Treatment Satisfaction Questionnaire for Medication (TSQM), Gastrointestinal Symptom Rating Scale (GSRS), and 12-item Short-Form Health Survey (SF-12v2). OS-MMAS scores can range from 0 to 8, with higher scores indicating better medication adherence. Internal consistency reliability was evaluated using Cronbach α coefficient. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs) in a subset of 102 participants. Construct validity was assessed using confirmatory factor analysis and correlations between OS-MMAS and related measures. RESULTS: Of 197 participants, 150 reported that they were still taking their bisphosphonate at the time of the survey and completed the OS-MMAS. Overall, 30.7%, 32.7%, and 36.7% had low, medium, and high OS-MMAS scores (<6, 6 to <8, and 8, respectively). Cronbach α was 0.82 and the ICC was 0.77. Convergent validity was supported by significant correlations with SEAMS, BMQ necessity, and TSQM scores. In confirmatory factor analysis, a single-factor scale was supported. CONCLUSIONS: The OS-MMAS showed strong psychometric properties with good reliability and construct validity and may provide a valuable assessment of self-reported medication adherence in women newly prescribed oral osteoporosis medications.

Trends in dual-energy X-ray absorptiometry in the United States, 2000-2009.

After a decade of policies encouraging dual-energy X-ray absorptiometry (DXA) use, Medicare incrementally decreased reimbursement for non-facility-based DXAs, effective 2007. This study quantifies trends in central DXA use before and after the reimbursement change. Using 2000-2009 claims data, we selected subjects aged 50+yr with Medicare supplemental or commercial insurance. The central site DXA test (using CPT codes) rate was calculated within each calendar quarter as the number of patients with a DXA test divided by the total number of patients. Piecewise linear regression was used to quantify change in DXA rates coincident with the 2007 reimbursement reductions. During 2000-2009, slightly over 5 million DXA tests were conducted. Annual rates for females with Medicare steadily increased until 2007, when they leveled off; a similar pattern was observed for the commercially insured. Regression modeling showed that pre-2007 rates increased annually by 0.76% (0.72-0.80) and 0.76% (0.70-0.82) among those with Medicare supplemental and commercial insurance, respectively, and over 2007-2009, rates changed annually by +0.07% (-0.05% to 0.19%) and -0.12% (-0.29% to 0.04%), respectively. During 2007-2009, there were 3.1 (2.4-3.8) and 4.0 (3.1-4.9) fewer tests per 100 person years for females with Medicare supplemental and commercial insurance, respectively, than would have been expected based on the pre-2007 trend. The post-2007 DXA rate was lower than what would have been expected had the observed trend of increasing annual DXA rates from 2000 to 2007 continued unabated beyond the Medicare reimbursement change in 2007. Continuing to provide access to DXA testing for women at increased risk of osteoporosis is important to providing high-quality care for metabolic bone disease in the United States.