A federal court has blocked the Bush administration's effort to save money on Medicare by paying for only the least expensive treatments for particular conditions. Congress sets Medicare payment rates and never intended to give officials broad discretion to alter them, the court said. The case, now being scutinized by Medicare officials and consumer advocates, involved drugs used to treat chronic obstructive pulmonary disease. Medicare officials have often tried to adopt regulations that allow them to consider cost in deciding whether the program should cover various goods and services. Healthcare providers, manufacturers, and some patients' advocates have resisted these efforts, saying that coverage decisions should be made based on clinical effectiveness and not cost.