Comparison of cost-effectiveness of vitamin D screening with that of universal supplementation in preventing falls in community-dwelling older adults

Abstract

Objectives: To compare the cost-effectiveness of population screening for vitamin D insufficiency with that of universal vitamin D supplementation in community-dwelling older adults.

Design: A Markov decision model simulating follow-up over a 36-month period. Published data were used to estimate values for the model, including costs (measured in 2011 U.S. dollars), utilities (measured in quality-adjusted life years (QALYs)), and probabilities.

Setting: Decision analysis simulation from a societal perspective.

Participants: Hypothetical cohort of community-dwelling women and men aged 65 to 80.

Measurements: Net monetary benefit (NMB) was calculated by subtracting the incremental cost of the strategy from the product of incremental QALYs and willingness-to-pay threshold. A higher NMB indicates greater cost-effectiveness.

Results: In women aged 65 to 80, population screening was slightly more cost-effective than universal supplementation, with an incremental NMB of $224 compared with $189 (P < .001). Population screening in men was also more cost-effective than universal supplementation (incremental NMB $298 vs $260, P < .001). Results differed according to age group. In those aged 65, population screening had cost-effectiveness similar to that of universal supplementation in women ($59 vs $71) and men ($114 vs $120), whereas in those aged 80, population screening was substantially more cost-effective than universal supplementation in women ($563 vs $428) and men ($703 vs $571).

Conclusion: Population screening and universal supplementation for vitamin D insufficiency are cost-effective strategies in community-dwelling older women and men. In the oldest old, population screening may be more cost-effective than universal supplementation.

Figure 1

Flow chart depicting possible health states and transitions for Markov model construction to simulate progression of events. At the start of each simulation, all subjects were assumed to be No Falls (without prior falls). Fall event outcomes include: 1) no injury, 2) injurious fall without hospitalization, and 3) injurious fall with hospitalization. Grey circles represent health states with lower age- and gender-specific utilities related to fall history. Death is a terminal node.

Figure 2

Decision tree illustrating the 3 modeled strategies and cohort constituents by vitamin D status. Ovals represent cohort with lowest falls risk. Diamonds represent cohort with improvement in falls risk due to vitamin D supplementation. Hexagons represent cohort with highest risk of falls. Note: For “No testing/treatment” strategy vitamin D insufficient and deficient groups combined, as falls risk assumed to be higher, given no vitamin D supplementation in either group.

Figure 3

Incremental net monetary benefit among older adults age 65 to 80 years, by gender. Willingness-to-pay threshold = US $50,000. Population screening (solid bars) and universal supplementation (striped bars). Note: more cost-effective strategy demonstrates higher incremental net monetary benefit.

Figure 4

Incremental net monetary benefit by sub-group of age and gender. Willingness-to-pay threshold = US $50,000. Population screening (solid bars) and universal supplementation (striped bars).