Results of the sensitivity analysis of test characteristics.

<p>The costs of selective PCR-based screening are depicted on the horizontal axis and health benefits (infections averted) on the vertical axis. The left graph shows the combined results of alternately varying the test’s sensitivity and specificity from 50% to 100%, with increments of 5%. The right graph shows the test delay varied from 0 to 5 days, with increments of 0.5 day, for different pre-emptive isolation strategies: No pre-emptive isolation (diamonds), pre-emptive isolation of ‘flagged’ patients only, i.e. the base-case scenario (squares), and full pre-emptive isolation, i.e. ‘flagged’ patients as well as ‘high risk’ patients (triangles).</p

Results of screening strategies.

<p>1 The number of patient days in isolation.</p><p>2 The peak isolation capacity required by the hospital in 97.5% of all simulations.</p><p>3 The number of years required to reach a 50% reduction in the nosocomial prevalence.</p><p>The cumulative and discounted costs in US$(2007) and discounted effects for one hospital over 15 years, using base-case assumptions, for a high (15 prevalence setting.</p><p><b>NA</b> not applicable; <b>aCER</b> average cost-effectiveness ratio in$ per infection averted, compared to no screening; <b>UI</b> uncertainty interval;</p

Results of the scenario analysis.

<p>1 The number of patient days in isolation.</p><p>2 The peak percentage of total patients in isolation in 97.5% of all simulations.</p><p>3 The number of years required to reach a 50% reduction in the nosocomial prevalence.</p><p>The cumulative and discounted costs in US$(2007) and discounted effects for one hospital over 15 years, for a high (15 cost-effectiveness ratio in$ per infection averted, compared to no screening; <b>UI</b> uncertainty interval;</p

Resource use and costs of screening and isolation in US$ (2007).

<p>1 The time required to estimate the risk of being a carrier was based on factors such as hospital admission within last 12 months or transfer from another healthcare facility (only in case of selective screening).</p><p>2 Annual cost based on Smartcycler (Cepheid, Sunnyvale, CA), straight line depreciation using an interest rate of 4%, a cost of $35,000, a lifetime of 10 years and a resale value of 20$1.04, including gloves ($0.057), gown ($0.46), mask ($0.27), hair cap ($0.049), disinfectant 75 mL ($0.20) required for each of 12 entries into an isolation room per day.</p><p>4 Additional cleaning costs are only incurred in case of a positive finding.</p><p>Labor costs are based on nationwide average hourly wages for registered nurses ($29.8), physicians ($66.3), clinical laboratory technologists and technicians ($24.4) and janitors and cleaners ($11.9). (source: bureau of labor statistics, US department of labor). A 24.3% administration overhead was applied to all labor costs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014783#pone.0014783-Woolhandler1" target="_blank">[<i>36</i>]</a>. Prices of consumables were provided by manufacturers.</p

Annual cost of screening and isolation, and rate of infection.

<p>The annual undiscounted cost in US$ (2007) of strategies ‘Selective PCR’ (left) and ‘Selective Chromogenic’ (right) in a high prevalence setting. The first two years represent baseline (no screening and no isolation).</p

Results of one-way sensitivity analysis on key model parameters.

<p>Parameters are ranked by the magnitude of their impact on the average cost-effectiveness ratio (aCER), of selective screening with PCR (aCER: $4,600) under base-case assumptions (base-case parameter values are shown between brackets).</p

Cost effectiveness planes for the high (top) and medium (bottom) prevalence setting.

<p>The investment costs in millions in US$ (2007) are depicted on the horizontal axis and health benefits (infections averted) on the vertical axis. The points shown represent the infections averted and investment costs of each screening strategy. The origin represents baseline, a policy of neither screening nor isolation. The incremental ratios of D effectiveness to costs are represented by the slopes of the lines connecting these points. The decreasing slope illustrates the diminishing return on investment when extending the selective PCR to universal screening in both settings. The strategy ‘Universal Chromogenic’ is dominated by ‘Selective PCR’ (higher costs, less health benefits), and is therefore not considered a relevant option. The incremental investment costs, infections averted and incremental cost-effectiveness ratio between selected strategies are shown in the table beneath the graphs. <b>iCER</b> incremental cost-effectiveness ratio; <b>Chr</b>. Chromogenic.</p

Total investment costs, savings and net benefit of strategies.

<p>Investment costs, savings (based on 17,645 averted hospital costs per averted infection ([6]) and net benefit in millions of US (2007), in high (left) and medium (right) prevalence settings.</p

Test characteristics.

<p>1 The chromogenic media-based test is evaluated after 24 and 48 hours of incubation. Patients with positive results are isolated at both time points, with the last result after 48 hours being considered final.</p