CALCIUM AND VITAMIN D FOR HIP FRACTURE PREVENTION IN LIGHT OF POSSIBLE CARDIOVASCULAR SIDE EFFECTS

Sunday, October 19, 2014
Poster Board # PS1-12

Candidate for the Lee B. Lusted Student Prize Competition

Gunhild Hagen, M.Phil., Institute of Public Health, Norwegian University of Science and Technology, Trondheim, Norway, Torbjørn Wisløff, M.Sc., Oslo University Hospital, Oslo, Norway and Ivar Sønbø Kristiansen, MD, PhD, MPH, University of Oslo, Oslo, Norway
Background: Calcium and vitamin D (Ca/VitD) has long been considered the cornerstone of hip fracture prevention and is in widespread use in older women. Recent research has raised concerns about possible cardiovascular side effects.

Purpose: To evaluate the net health benefits and cost effectiveness of treating elderly women with Ca/VitD for hip fracture prevention accounting for potential cardiovascular side effects.

Method: We created a probabilistic Markov simulation model including the events hip fracture, acute myocardial infarction (AMI) and death and the health states long term nursing home care, heart failure, healthy, and death. We analysed a cohort of 75 year old women with average risk of hip fracture, 10 year risk of hip fracture of 7%. The model employed a cycle length of one year and patients were followed until 100 years of age or until death. Baseline risk of events, costs and quality of life were based on published values. Mortality risks were provided by Statistics Norway. Parameter values were expressed as distributions, and all costs and future QALYs were discounted at 4%. Sensitivity analysis was performed by means of Monte Carlo simulation.

Risk of AMI when using calcium was based on Bolland et al. 2011, RR=1.21 (95% CI 1.01 to 1.44). The relative risk of hip fracture when using Ca/VitD RR=0.84, (95% CI 0.74 to 0.96) was based on a recently updated Cochrane review.

Cost of one year supplementation with Ca/VitD was EUR 236.

Result: Lifetime treatment of 10 000 women with Ca/VitD resulted in 390 hip fractures prevented and 356 additional myocardial infarctions as compared to no treatment. The discounted lifetime costs were EUR 382 933 with Ca/VitD vs EUR 380 606 on no treatment. The expected QALYs were 5.5697 and 5.5576, respectively.

In the probabilistic sensitivity analysis, Ca/VitD had a probability of 3% of being considered a cost effective alternative, assuming a threshold value of EUR 62 000 per QALY gained. The results are highly dependent on mortality risk increases following both hip fracture and AMI and also on the price of Ca/VitD supplementation.

Conclusion:  Under the assumptions made, Ca/VitD is unlikely to be considered a cost effective alternative for hip fracture prevention.

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