Sensitivity analyses
One-way and tornado diagram showed that the probability of hospitalization has the highest impact on the outcome, but MS was the dominant strategy in all range of probabilities analyzed. The results of PSA are graphically represented in the cost-effectiveness plane,figure 2 . 70.87% of simulations were graphed in quadrant 2 (lower cost , high QALYs) , and 28.4% in quadrant 1 of this plane (high cost, high QALYs) . The 95% CI for the cost per patient treated with SM and with standard treatment were US$ 1042 to 1257, and US$ 1471 to 1725. The 95% CI for QALYs per patient was 0.59 to 0.62 , and 0.51 to 0.54 respectively. The Cost-effectiveness acceptability curve shows that the probabilty that MS provides a more cost-effective use of resources compared with standard therapy exceeds 99% for all willingness to pay thresholds. The population expected value of perfect information (EVPIP) for threshold of US$ 20 000 (threshold of 3 times the Colombian per capita gross domestic product) was US$ 221517 which was 15 times less than maximum EVPIP simulated by the model.