Vitamin K supplementation for the primary prevention of osteoporotic fractures: is it cost-effective and is future research warranted?

UNLABELLED: Lifetime supplementation with vitamin K, vitamin D(3), and calcium is likely to reduce fractures and increase survival in postmenopausal women. It would be a cost-effective intervention at commonly used thresholds, but high uncertainty around the cost-effectiveness estimates persists. Further research on the effect of vitamin K on fractures is warranted. INTRODUCTION: Vitamin K might have a role in the primary prevention of fractures, but uncertainties about its effectiveness and cost-effectiveness persist. METHODS: We developed a state-transition probabilistic microsimulation model to quantify the cost-effectiveness of various interventions to prevent fractures in 50-year-old postmenopausal women without osteoporosis. We compared no supplementation, vitamin D(3) (800 IU/day) with calcium (1,200 mg/day), and vitamin K(2) (45 mg/day) with vitamin D(3) and calcium (at the same doses). An additional analysis explored replacing vitamin K(2) with vitamin K(1) (5 mg/day). RESULTS: Adding vitamin K(2) to vitamin D(3) with calcium reduced the lifetime probability of at least one fracture by 25%, increased discounted survival by 0.7 quality-adjusted life-years (QALYs) (95% credible interval (CrI) 0.2; 1.3) and discounted costs by $8,956, yielding an incremental cost-effectiveness ratio (ICER) of $12,268/QALY. At a $50,000/QALY threshold, the probability of cost-effectiveness was 95% and the population expected value of perfect information (EVPI) was $28.9 billion. Adding vitamin K(1) to vitamin D and calcium reduced the lifetime probability of at least one fracture by 20%, increased discounted survival by 0.4 QALYs (95% CrI -1.9; 1.4) and discounted costs by $4,014, yielding an ICER of $9,557/QALY. At a $50,000/QALY threshold, the probability of cost-effectiveness was 80% while the EVPI was $414.9 billion. The efficacy of vitamin K was the most important parameter in sensitivity analyses. CONCLUSIONS: Lifetime supplementation with vitamin K, vitamin D(3), and calcium is likely to reduce fractures and increase survival in postmenopausal women. Given high uncertainty around the cost-effectiveness estimates, further research on the efficacy of vitamin K on fractures is warranted.

The cost effectiveness of a randomized controlled trial to establish the relative efficacy of vitamin K1 compared with alendronate.

PURPOSE: The authors aimed to evaluate whether vitamin K(1) or alendronate (the recommended treatment in England and Wales for postmenopausal women with a previous fracture) appeared to be the more cost-effective treatment for fracture prevention. Furthermore, expected value of sample information (EVSI) analyses were undertaken to estimate whether a head-to-head trial of alendronate and vitamin K(1) would be considered cost effective. METHOD: A published osteoporosis model structure, populated with data from literature reviews, was used to evaluate the costs and quality-adjusted life-years associated with each intervention being provided to women at high risk of fracture, given current information. A lifetime horizon and a national health service and personal social services cost perspective were used. Observed outcomes from head-to-head randomized controlled trials (RCTs) of predetermined sizes were simulated and synthesized with existing data to formulate posterior distributions, which were used to estimate the more cost-effective treatment given these additional data. The EVSI was estimated and the expected net benefit of sampling (ENBS) calculated by subtracting the proposed trial costs. RESULTS: Given current information, vitamin K(1) is expected to dominate alendronate. However, this was subject to a considerable degree of uncertainty; dominance was reversed when it was assumed that vitamin K(1) had no effect on hip fractures. EVSI analysis indicated that an RCT of 2000 or 5000 women per arm produced high, and comparable, ENBS. These results were maintained in sensitivity analyses. CONCLUSIONS: It is concluded that an RCT recruiting between 2000 and 5000 women per arm to evaluate the relative efficacy of alendronate and vitamin K(1) appears to be cost effective for informing decision making in England and Wales.

Vitamin K to prevent fractures in older women: systematic review and economic evaluation.

OBJECTIVE: To determine the clinical and cost-effectiveness of vitamin K in preventing osteoporotic fractures in postmenopausal women. DATA SOURCES: Searches were conducted in May 2007 in MEDLINE, MEDLINE In-Process, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, BIOSIS, CINAHL, DARE, NHS EED and HTA databases, AMED, NRR, Science Citation Index and Current Controlled Trials. The MEDLINE search was updated in March 2009. REVIEW METHODS: Selected studies were assessed and subjected to data extraction and quality assessment using standard methods. Where appropriate, meta-analysis was carried out. A mathematical model was constructed to estimate the cost-effectiveness of vitamin K1. RESULTS: The electronic literature searches identified 1078 potentially relevant articles. Of these, 14 articles relating to five trials that compared vitamin K with a relevant comparator in postmenopausal women with osteoporosis or osteopenia met the review inclusion criteria. The double-blind ECKO trial compared 5 mg of phylloquinone (vitamin K1) with placebo in Canadian women with osteopenia but without osteoporosis. Four open-label trials used 45 mg of menatetrenone (vitamin K2) in Japanese women with osteoporosis; the comparators were no treatment, etidronate or calcium. The methodological quality of the ECKO trial was good; however, all four menatetrenone trials were poorly reported and three were very small (n < 100 in each group). Phylloquinone was associated with a statistically significant reduction in the risk of clinical fractures relative to placebo [relative risk 0.46, 95% confidence interval (CI) 0.22 to 0.99]; morphometric vertebral fractures were not reported. The smaller menatetrenone trials found that menatetrenone was associated with a reduced risk of morphometric vertebral fractures relative to no treatment or calcium; however, the larger Osteoporosis Fracture (OF) study found no evidence of a reduction in vertebral fracture risk. The three smaller trials found no significant difference between treatment groups in non-vertebral fracture incidence. In the ECKO trial, phylloquinone was not associated with an increase in adverse events. In the menatetrenone trials, adverse event reporting was generally poor; however, in the OF study, menatetrenone was associated with a significantly higher incidence of skin and skin appendage lesions. No published economic evaluations of vitamin K were found and a mathematical model was thus constructed to estimate the cost-effectiveness of vitamin K1. Comparators were alendronate, risedronate and strontium ranelate. Vitamin K1 and alendronate were markedly more cost-effective than either risedronate or strontium ranelate. The base-case results favoured vitamin K1, but this relied on many assumptions, particularly on the efficacy of preventing hip and vertebral fractures. Calculation of the expected value of sampled information was conducted assuming a randomised controlled trial of 5 years' duration comparing alendronate with vitamin K1. The costs incurred in obtaining updated efficacy data from a trial with 2000 women per arm were estimated to be a cost-effective use of resources. CONCLUSIONS: There is currently large uncertainty over whether vitamin K1 is more cost-effective than alendronate; further research is required. It is unlikely that the present prescribing policy (i.e. alendronate as first-line treatment) would be altered.