showed a trendP = 0.006
Adding interaction terms for interferon plus lopinavir/ritonavir, interferon plus ribavirin, and lopinavir/ritonavir plus ribavirin in the Cox‐PH regression analysis showed a trend toward synergy between interferons and ribavirin in the full dataset (AHR = 6.04, P = 0.006; Figure 3 ), as well as in the additional analysis taking in quality assessments to account for potential bias: respiratory data limited to drug quality and in data limited to only viral load quality 1 data ( Figure S4 , Figure S5 ).