Cost-effectiveness of different screening strategies for osteoporosis in postmenopausal women

Abstract

Background: The best strategies to screen postmenopausal women for osteoporosis are not clear.

Objective: To identify the cost-effectiveness of various screening strategies.

Design: Individual-level state-transition cost-effectiveness model.

Data sources: Published literature.

Target population: U.S. women aged 55 years or older.

Time horizon: Lifetime.

Perspective: Payer.

Intervention: Screening strategies composed of alternative tests (central dual-energy x-ray absorptiometry [DXA], calcaneal quantitative ultrasonography [QUS], and the Simple Calculated Osteoporosis Risk Estimation [SCORE] tool) initiation ages, treatment thresholds, and rescreening intervals. Oral bisphosphonate treatment was assumed, with a base-case adherence rate of 50% and a 5-year on/off treatment pattern.

Outcome measures: Incremental cost-effectiveness ratios (2010 U.S. dollars per quality-adjusted life-year [QALY] gained).

Results of base-case analysis: At all evaluated ages, screening was superior to not screening. In general, quality-adjusted life-days gained with screening tended to increase with age. At all initiation ages, the best strategy with an incremental cost-effectiveness ratio (ICER) of less than $50,000 per QALY was DXA screening with a T-score threshold of -2.5 or less for treatment and with follow-up screening every 5 years. Across screening initiation ages, the best strategy with an ICER less than $50,000 per QALY was initiation of screening at age 55 years by using DXA -2.5 with rescreening every 5 years. The best strategy with an ICER less than $100,000 per QALY was initiation of screening at age 55 years by using DXA with a T-score threshold of -2.0 or less for treatment and then rescreening every 10 years. No other strategy that involved treatment of women with osteopenia had an ICER less than $100,000 per QALY. Many other strategies, including strategies with SCORE or QUS prescreening, were also cost-effective, and in general the differences in effectiveness and costs between evaluated strategies was small.

Results of sensitivity analysis: Probabilistic sensitivity analysis did not reveal a consistently superior strategy.

Limitations: Data were primarily from white women. Screening initiation at ages younger than 55 years were not examined. Only osteoporotic fractures of the hip, vertebrae, and wrist were modeled.

Conclusion: Many strategies for postmenopausal osteoporosis screening are effective and cost-effective, including strategies involving screening initiation at age 55 years. No strategy substantially outperforms another.

Primary funding source: National Center for Research Resources.

Figure

Model schematic. This is a simplified and partial representation of the full model. The model evaluates 7 screening strategies, each of which was evaluated as a 1-time strategy, as a strategy repeated every 5 years, and as a strategy repeated every 10 years; additionally, no screening was also considered, resulting in a total of 22 screening options at each screening initiation age; these are described in more detail in Table 1. The screening result is either positive, in which case the individual is offered treatment with a bisphosphonate, or negative, in which case usual care of calcium and vitamin D is offered. We assume that at the time of initial screening individuals are in the “no fracture” state, with no known history of osteoporotic fracture. Whether on or off treatment, patients may experience a series of events over time, including a new osteoporotic fracture, the results of which may be death, transfer to a long-term care facility, or recovery. Patients may also experience medication adverse events. Individuals move through the outcomes and fracture states portions of the model on a 3-month cycle.