Hepatology Table 2 Proportion of end of treatment response (ETR) and sustained viral response (SVR) with pegylated interferon during 6 months, according to timing of therapy after exposure36 Table 4 Costs, QALYs and C/E ratios associated with four follow-up strategies for HCWs occupationally exposed to HCV according to average risk of HCV transmission Timing of therapy Month 3 after exposure Month 4 after exposure Month 6 after exposure ETR (%) 95.3 91.8* 84.8* SVR (%) 93.2 84.9* 68.3* *In the study of Kamal et al,36 ETR and SVR were observed for patients starting therapy at month 3 and month 5. We extrapolated ETR and SVR for patients starting therapy at month 4 and month 6 from these data according to a linear function. costs were obtained with the French strategy (J1 324 220 ) and the lowest with the baseline-US strategy (J924 180). The times to HCV infection diagnosis ranged from 1.0 for the alternative- US strategy to 6.0 months for the baseline-US strategy. Thus, the baseline-US strategy was the cheapest but was associated with the longest time to HCV infection diagnosis. In contrast, the alternative-US strategy was one of the most expensive but was associated with the shortest time to diagnosis. Moreover, it was associated with the lowest number of patients with CHC (1.9 vs 7.9 for the baseline-US strategy) and the highest number of CHC avoided by acute HCV treatment (25.1 vs 17.7 for the baseline-US strategy). Table 4 shows the incremental costs, utilities and incremental C/E ratio for the baseline HCV transmission risk. Compared with the alternative-US strategy, the French strategy was associated with higher costs and lower utilities, and the European strategy with a higher incremental C/E ratio. Compared with the baseline- US strategy, the alternative-US strategy was associated with an incremental C/E ratio of J2020 per QALY saved. Sensitivity analysis Table 5 shows the incremental costs, utilities and incremental C/E ratio for low and high HCV transmission risk. When we considered patients at low risk of HCV transmission, the C/E ratio of the alternative-US strategy compared with the baseline- US strategy was at J6102 per QALY saved. When the risk of HCV transmission was high, the baseline-US strategy was no longer the cheapest strategy because a higher number of CHC cases, which are associated with high costs, occurred with this strategy than with other strategies. The European strategy became the cheapest strategy, and the C/E ratio of the alternative-US strategy compared with the European strategy was at J695 per QALY saved. Strategy Baseline-US European Alternative-US French Costs per HCW (J) 126.60 155.10 178.50 181.40 QALYs 23.2292 23.2409 23.2549 23.2396 Incremental C/E ratio Weakly dominated* J2020 Strongly dominated{ *A weakly dominated strategy a higher incremental C/E ratio than that of a more effective alternative strategy—that is, the incremental C/E ratio of the European strategy vs the baseline-US is higher than the incremental C/E ratio of the alternative- US strategy vs the European strategy. {A strongly dominated strategy indicates a higher cost than that of a more effective alternative strategy—that is, the French strategy is associated with a higher cost and a lower utility compared with the alternative-US strategy. C/E, cost-effectiveness; HCV, hepatitis C virus; HCW, healthcare worker; QALY, quality-adjusted life year. When we varied the health-related quality of life of HCWs, while waiting for their HCV status and we assigned a utility of 0.99 per month (vs 0.86 at month 1, 0.90 at month 2, 0.94 at month 3, and 0.98 thereafter in the base case analysis), first the European strategy was no longer dominant and when compared with the baseline-US strategy it was associated with a C/E ratio of J3314 per QALY saved. Compared with the European strategy, the alternative-US strategy was still associated with a reasonable C/E ratio of J8069 per QALY saved. When we assumed that waiting for HCV status had no impact on the HCW’s quality of life (utilities at 1), compared with the baseline-US strategy the C/E ratio of the European strategy was estimated at J3958 per QALY saved. Compared with the European strategy, the C/E ratio of the alternative-US strategy was estimated at J234 000 per QALY saved. Results were robust to variations in: (1) distributions used to model the appearance of anti-HCV antibodies, ALT elevation and HCV RNA detection; (2) in the proportion of the subjects who spontaneously cleared HCV during the acute phase; and (3) the cost of treatment and follow-up of CHC. DISCUSSION In this study, the cost and effectiveness of four strategies for follow-up after occupational exposure to HCV were compared. Although more expensive, a strategy based on early HCV RNA testing was found to be associated with a reasonable C/E ratio compared with strategies based on ALT detection and/or Table 3 Direct medical costs, mean time to HCV diagnosis, number of patients who developed CHC and number of CHC cases avoided by early therapy, associated with different follow-up strategies in 7300 French HCWs occupationally exposed to HCV Costs* (J) Mean time to HCV diagnosis{ (months) No of CHC cases avoided by acute HCV No of CHC cases treatment Strategy French strategy based on anti-HCV 1 324 220 antibody and ALT monitoring (strategy 1) European strategy based on ALT 1 132 230 monitoring (strategy 2) Baseline-US strategy based on anti-HCV 924 180 antibody and ALT monitoring (strategy 3) Alternative-US strategy based on HCV 1 303 050 RNA testing (strategy 4) 2.2 2.0 6.0 1.0 *Estimated costs from exposure to death. {Mean time from exposure to HCV diagnosis. ALT, alanine transaminase; CHC, chronic hepatitis C; HCV, hepatitis C virus; HCW, healthcare worker. 2.0 2.1 7.9 1.9 24.9 24.9 17.7 25.1 108 Gut 2009;58:105–110. doi:10.1136/gut.2007.145516