Osteoporosis screening strategies shown to be generally equal, effective

Several strategies to screen postmenopausal women for osteoporosis are about equally effective, and screening from ages 55 to 80 years was cost-effective, concluded the authors of a modeling study.

Although the “best” strategy was screening with dual-energy X-ray absorptiometry (DXA), treating if the T-score was −2.5 or less, and rescreening every five years, other strategies were just as effective for those who could not travel or did not have access to DXA, the authors concluded.

The model compared the cost-effectiveness of nine osteoporosis screening strategies, including universal screening and treatment for those with osteoporosis according to bone mineral density (BMD) criteria, for postmenopausal women. The model began screening in five-year intervals from ages 55 to 80 years. Results appeared in the Dec. 6 Annals of Internal Medicine.

The model estimated quality-adjusted life-years (QALY), costs in 2010 U.S. dollars, and incremental cost-effectiveness ratios (ICERs) for the screening strategies. The ICERs represent cost per QALY gained for a particular strategy compared to another strategy. The model allowed direct comparison of multiple screening tests and sequences of tests, screening initiation ages, treatment thresholds and repeat screening intervals.

All of the most effective strategies involved screening starting at age 55, the authors said. Screening continued to be effective and cost-effective up to 80 years of age, and in general, quality-adjusted life-days gained with screening tended to increase with older age. In addition, strategies involving screening with DXA, rather than calcaneal quantitative ultrasonography (QUS) or Simple Calculated Osteoporosis Risk Estimation (SCORE) prescreening, were most effective, although the differences between strategies were on the order of quality-adjusted life-days.

The best strategy with an ICER less than $50,000 per QALY was initiating screening at 55 years of age using DXA, treating if the T-score was −2.5 or less, and rescreening every five years. If the model assumed a willingness to pay of $100,000 per QALY, screening at age 55 years with DXA, initiating treatment at a T-score of −2.0 or less, and rescreening every 10 years was the best strategy.

The most effective strategy across the starting ages was screening with DXA at age 55 years, treating at a T-score of −1.5 or less, and rescreening every five years. However, this strategy was very expensive, with an ICER of nearly $700,000 per QALY.

Several strategies involving SCORE prescreening or QUS prescreening were more cost-effective than strategies involving screening initiation with DXA, with ICERs less than $30,000 per QALY.

The authors noted that results do not indicate clear superiority of a repeated screening interval of five years versus every 10 years. Instead, it's likely that the best repeated screening interval may vary according to previous DXA T-scores.

“For women with limited access to DXA or those who prefer not to travel for DXA screening if possible, our findings show that the SCORE tool and QUS for prescreening are reasonable alternatives,” the authors wrote. “Because other studies have shown the Osteoporosis Self-Assessment Tool and Osteoporosis Risk Assessment Instrument to perform similarly to the SCORE tool, we expect that these too may be acceptable alternatives.”

An editorial commented that the analysis showed that DXA is cost-effective for women aged 55 to 64 years who have an average risk for fracture and a likelihood of having osteoporosis by BMD criteria. It also confirmed that other bone densitometry technologies, such as peripheral ultrasonography, are reasonable when central DXA is not available.

However, it is too soon to conclude that universal bone densitometry for all white women aged 55 to 64 years is cost-effective, the editorial stated. The model significantly overestimated rates of hip fracture for women aged 55 to 64 years and wrist fracture, according to the authors.

Instead, the editorial concluded, “We suspect that the ‘truth’ may lie somewhere between the base-case analyses and these sensitivity analyses. Additional studies with well-calibrated models examining the cost-effectiveness of universal bone densitometry for women aged 55 to 64 years compared with bone densitometry only for subsets with a higher pretest probability of osteoporosis selected with a prescreening measure are still needed.”