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It is important to note the reason for the difference in the outcomes. It is possible, in the real-world conditions that exist in registry data, that patients who can tolerate beta blockers (patients without hypotension and severe LV dysfunction) are put on beta blockers. Therefore a good outcome compared to those without beta blockers is to be expected. Likewise, in low-risk patients (patients without angina and LV dysfunction, even of mild degree) beta blockers were discontinued. Therefore this group is likely to do better otherwise (without beta blockers) also. Therefore no benefit of continuation of beta blockers was observed.
Such factors must be considered before applying the message from registry data.