A Markov model with a 17-year time horizon was developed to determine the long-term costs and benefits of the intervention. The authors stated that a societal perspective and a third-party payer (statutory health insurance) perspective were adopted.
The clinical data were mainly derived from the published literature. The data on the effectiveness of hip protectors were from a published meta-analysis and the details of this and the methods used to identify the sources were reported. Cumulative transition probabilities were derived from published studies and were converted to biannual transition probabilities, for the six-month cycle of the model. The methods used were provided in a separate appendix. The main clinical outcomes were the fracture risk and relative risk with and without the hip protector.
Monetary benefit and utility valuations:
The utility values were derived from two studies that used the European Quality of life (EQ-5D) questionnaire. The weights used to calculate the EQ-5D scores were obtained from a UK population survey using the time trade-off method.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure. Benefits were discounted at an annual rate of 3%.
The economic analysis considered the costs of materials and implementation for hip protectors, including training and nursing staff and their expenses, nursing home, hip-fracture surgery, rehabilitation care, in-patient care, and transportation. All relevant assumptions were reported. These costs were from official national sources, apart from hip protector implementation costs, which were from a previous study. All costs were expressed in Euros (EUR) at 2004 prices and the discount rate was 3%.
Analysis of uncertainty:
The parameter uncertainty was investigated using one-way sensitivity analysis and probabilistic sensitivity analysis, using Monte Carlo simulations. The probability distributions were reported. Cost-effectiveness acceptability curves were generated, using the net monetary benefit method, for different willingness-to-pay values.