Cost-effective osteoporosis treatment thresholds: the United States perspective

Abstract

A United States-specific cost-effectiveness analysis, which incorporated the cost and health consequences of clinical fractures of the hip, spine, forearm, shoulder, rib, pelvis and lower leg, was undertaken to identify the 10-year hip fracture probability required for osteoporosis treatment to be cost-effective for cohorts defined by age, sex, and race/ethnicity. A 3% 10-year risk of hip fracture was generally required for osteoporosis treatment to cost less than $60,000 per QALY gained.

Introduction: Rapid growth of the elderly United States population will result in so many at risk of osteoporosis that economically efficient approaches to osteoporosis care warrant consideration.

Methods: A Markov-cohort model of annual United States age-specific incidence of clinical hip, spine, forearm, shoulder, rib, pelvis and lower leg fractures, costs (2005 US dollars), and quality-adjusted life years (QALYs) was used to assess the cost-effectiveness of osteoporosis treatment ($600/yr drug cost for 5 years with 35% fracture reduction) by gender and race/ethnicity groups. To determine the 10-year hip fracture probability at which treatment became cost-effective, average annual age-specific probabilities for all fractures were multiplied by a relative risk (RR) that was systematically varied from 0 to 10 until a cost of $60,000 per QALY gained was observed for treatment relative to no intervention.

Results: Osteoporosis treatment was cost-effective when the 10-year hip fracture probability reached approximately 3%. Although the RR at which treatment became cost-effective varied markedly between genders and by race/ethnicity, the absolute 10-year hip fracture probability at which intervention became cost-effective was similar across race/ethnicity groups, but tended to be slightly higher for men than for women.

Conclusions: Application of the WHO risk prediction algorithm to identify individuals with a 3% 10-year hip fracture probability may facilitate efficient osteoporosis treatment.

Figure 1

Model health states and initial transitions. Shaded circles show acute events.

Figure 2

Model validation results comparing two modeling approaches for white women where fractures modeled include hip, wrist, spine, and other (proximal humerus, rib, pelvis, and tibia/fibula). Approach 1 modeled age-specificfracture incidence-making no distinction between first and subsequent fractures. Approach 2 modeled age-specific incidence of first fracture and increased the rate at which subsequent fractures occurred.

Figure 3

Absolute 10-year hip fracture risk by age and race at which it is cost-effective to treat (shown by lines) and average 10-year hip fracture risk by age and race (shown by vertical bars) for A) women and B) men in the United States.

Figure 3

Absolute 10-year hip fracture risk by age and race at which it is cost-effective to treat (shown by lines) and average 10-year hip fracture risk by age and race (shown by vertical bars) for A) women and B) men in the United States.

Figure 4

Among white women, the impact of drug treatment cost ($300, $600 or $900 per year) and willingness-to-pay threshold ($50K, $60K, or $75K per QALY gained) on (A) relative risk required to achieve cost-effectiveness where relative risks are computed using 10-year average risk of fracture for the general population at each age (B) absolute 10-year hip fracture risk at which treatment becomes cost-effective in the United States.

Figure 4

Among white women, the impact of drug treatment cost ($300, $600 or $900 per year) and willingness-to-pay threshold ($50K, $60K, or $75K per QALY gained) on (A) relative risk required to achieve cost-effectiveness where relative risks are computed using 10-year average risk of fracture for the general population at each age (B) absolute 10-year hip fracture risk at which treatment becomes cost-effective in the United States.

Figure 5

The impact that duration in fracture-related loss in quality of life (5-year, 10-year or lifetime duration) has on the absolute 10-year risk of hip fracture at which treatment becomes cost-effective is shown for white women in the United States.