Rating agency Standard & Poor's lowered the debt rating on Boston Medical Center as the financially troubled hospital posted an operating loss of $24.5 million for the 12 months ending Sept. 30, its first in five years. Standard & Poor's cited the Massachusetts state government's reduced support for Boston Medical Center in a statement accompanying the downgrade, and warned that a further cut in the debt rating was a possibility. Reductions in state and federal aid were also cited by the hospital in its fiscal 2009 financial report to regulators, the Boston Globe reports.