Aetna Inc. became the last of the five major national health insurers to project a loss on Affordable Care Act plans for 2016, underscoring concerns about the stability of the insurance marketplaces at the heart of the Obama administration’s signature health law.

Five Southern Nevada hospitals were among six statewide that received only one star in a controversial five-star rating system unveiled Wednesday by the Centers for Medicare & Medicaid Services.

Research released Monday finds comparable safety and efficacy for one type of biosimilar drugs, complex medicines intended to be near-copies of some of the most costly prescription drugs on the market, but highlights the need for more information on the products.

The federal government released its first overall hospital quality rating on Wednesday, slapping average scores on some of California’s best-known medical centers while awarding top scores to unheralded ones.

It is no secret that the cost and quality of health care can vary greatly within a state as large as California. But by how much?