The predicted lifetime costs and health consequences of calcium and vitamin D supplementation for fracture prevention-the impact of cardiovascular effects

Some studies indicate that calcium supplementation increases cardiovascular risk. We assessed whether such effects could counterbalance the fracture benefits from supplementation. Accounting for cardiovascular outcomes, calcium may cause net harm and would not be cost-effective. Clinicians may do well considering cardiovascular effects when prescribing calcium supplementation. Accounting for possible cardiovascular effect of calcium and vitamin D supplementation (CaD), the aims of this study were to assess whether CaD on balance would improve population health and to evaluate the cost-effectiveness of such supplementation. We created a probabilistic Markov simulation model that was analysed at the individual patient level. We analysed 65-year-old Norwegian women with a 2.3 % 10-year risk of hip fracture and a 9.3 % risk of any major fracture according to the WHO fracture risk assessment tool (FRAXA (R)). Consistent with a recent Cochrane review, we assumed that CaD reduces the risk of hip, vertebral, and wrist fractures by 16, 11, and 5 %, respectively. We included the increased risk of acute myocardial infarction (AMI) and stroke under a no-, medium-, and high-risk scenario. Assuming no cardiovascular effects, CaD supplementation produces improved health outcomes resulting in an incremental gain of 0.0223 quality-adjusted life years (QALYs) and increases costs by a,not sign322 compared with no treatment (cost-effectiveness ratio a,not sign14,453 per QALY gained). Assuming a Norwegian cost-effectiveness threshold of a,not sign60,000 per QALY, CaD is likely to be considered a cost-effective treatment alternative. In a scenario with a medium or high increased risk of cardiovascular events, CaD produces net health losses, respectively, -0.0572 and -0.0784 QALY at additional costs of a,not sign481 and a,not sign1033. We conclude that the magnitude of potential cardiovascular side effects is crucial for the effectiveness and cost-effectiveness of CaD supplementation in elderly women.