With unemployment rising in a sputtering U.S. economy, many analysts and investors expected hospital chains to take a hit in the recent first quarter from more uninsured patients coming through their doors. But so far, earnings reports from companies show uninsured admissions remain stable-to-declining. Analysts, however, warn against declaring the first-quarter results a trend. They say the declines could simply reflect the fact that people who lost health insurance benefits are putting off care, or that COBRA and public programs such as Medicaid are picking up the slack.