New York City hospitals are the least reliable in the state at reporting preventable mistakes and adverse incidents for patients like heart attacks, blood clots, hospital infections, and medication errors, according to a new report by the office of City Comptroller. Though New York City hospitals accounted for almost half the patients statewide in 2006, they reported about 39 adverse incidents per 10,000 patient discharges, compared with nearly 70 per 10,000 in the northern suburbs and upstate and nearly 64 per 10,000 on Long Island. The comptroller also expressed concern that the New York City data on medication errors appear to run counter to the national trend.