Surviving a life-threatening illness or injury may be more likely if you're treated at a busy emergency department instead of one that handles fewer patients, a new study finds. Researchers analyzed data on 17.5 million emergency patients treated at nearly 3,000 hospitals across the United States. The overall risk of death in the hospital was 10 percent lower among those who initially went to the busiest emergency departments rather than to the least busy ones, the study found. The survival difference was even greater for patients with serious, time-sensitive conditions.