Despite new state and federal laws aimed at reining in aggressive collection practices, North Carolina's largest hospital system continues to file hundreds of lawsuits each year to collect on unpaid bills. Since 2013, nonprofit Carolinas HealthCare System has filed more than 2,700 bill-collection lawsuits against patients, state records show. An Observer review found that a number of those lawsuits were filed against low-income patients who lacked health insurance. That appears to defy the intent of new laws aimed at protecting vulnerable patients, advocates say. Carolinas HealthCare, the Charlotte-based hospital chain that runs Carolinas Medical Center and about 40 other hospitals, says it follows the law.