Jan 14 (Reuters) - The U.S. Food and Drug Administration appears skeptical that data submitted by Johnson & Johnson proves its anticoagulant Xarelto is effective in reducing the risk of further heart problems in patients who have suffered a heart attack.

The review was posted on the FDA's website on Tuesday, two days ahead of a meeting of outside experts who will discuss the drug, also known as rivaroxaban, and recommend whether it should be approved. The company is recommending it be used in the first 90 days following a heart attack.

"It is unclear how to choose the metric for determining when the benefit of rivaroxaban is greatest," the review found. "Not only does the effect of rivaroxaban not appear to be greater earlier, but an effect in the first 90 days or so is not apparent at all."