In what might be an unintended consequence of health care improvement efforts, older heart attack patients seem less likely to get stents in the U.S. states that require hospitals to report the outcomes of such procedures, according to a new study. Some believe public reporting allows patients to pick the best hospitals while encouraging hospitals to perform better, according to the researchers. But some fear such reporting also discourages doctors from performing risky but necessary procedures. The study's researchers, who reported their findings in the Journal of the American Medical Association on Tuesday, say they can't tell whether the difference is from doctors forgoing needed procedures, doctors being better at selecting when to do procedures, or something else.