Bar graph depicting patient characteristics before mitral valve repair or replacement. Unadjusted values are depicted in set of graphs and propensity matched patients in the other. The difference in characteristics between the groups is noticeably more pronounced without propensity matching.

FIGURE 2-3Comparison of patient characteristics before mitral valve repair (black bars) or replacement (unshaded bars)

Unadjusted values are depicted in A and propensity-matched patients in B.

NOTE: COPD = chronic obstructive pulmonary disease; LVEF = left ventricular ejection fraction; NYHA = New York Heart Association.

From: 2, The Work Required

Cover of Learning What Works
Learning What Works: Infrastructure Required for Comparative Effectiveness Research: Workshop Summary.
Institute of Medicine (US) Roundtable on Value & Science-Driven Health Care.
Washington (DC): National Academies Press (US); 2011.
Copyright © 2011, National Academy of Sciences.

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