Cost-effectiveness
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The costs of adopting the intervention will be prospectively collected from hospital records, such as the cost of cleaning consumables. Excess length-of-stay estimates will be sourced from studies identified by systematic reviews to estimate the value of bed days saved. The cost-effectiveness of the intervention will be evaluated from the perspective of the hospital decision-maker. Cost-effectiveness will be summarised by the incremental cost-effectiveness ratio and net monetary benefit, which offer different summaries of the change in costs versus health benefits. Modelled changes in the primary outcome (HAIs) will be used to estimate changes in health benefits from cases prevented by the intervention, as quality-adjusted life year (QALY). Probabilistic sensitivity analysis will be undertaken to account for uncertainty in model parameters and its impact on cost-effectiveness outcomes.Uncertainties in parameter estimates will be captured using appropriate statistical distributions to describe the variability. The fitted distributions will be subject to random re-samples simulated 10,000 times. The distributions of all prior parameters are used to estimate the posterior distributions of ‘change to costs’ and ‘change to QALY’ outcomes. The decision will be informed by plotting cost-effectiveness acceptability curves with threshold values between zero and 100,000 per QALY gained and using the net monetary benefits framework. These approaches are semi-Bayesian and appropriately account for all parameter uncertainty for the adoption decisions.