Figure 1.

Direct and indirect comparisons. Circled letters represent trial arms of drug A (A), drug B (B), drug C (C), and placebo (P). Flat lines represent direct trials, dotted lines represent indirect comparisons. Example 1: Direct comparison of drug A and drug B. Example 2: Adjusted indirect comparison where drug A and drug B have not been evaluated directly. Example 3: A multiple treatment comparison where drug A and drug C, drug B and placebo, and drug C and placebo have not been evaluated directly.