FIG. 1.

Regression tree analysis for efavirenz (EFV). Fold change in IC₅₀ (FC) for EFV was the target variable, and all individual mutations present unmixed in greater than 1% of samples with NNRTI resistance and Fisher's exact test P value of >0.1 (after adjustment for multiple comparisons) were considered potential predictor variables. Mutations were scored as 0 if absent and 1 if present; mixtures were scored as 0.5. Mutations in bold type and gray shading represent those associated with an increased EFV FC.