Kentucky's new insurance commissioner said he has approved Aetna's plan to take over Louisville-based Humana. The Courier-Journal reports the news emerged Wednesday after commissioner Brian Maynard was asked to explain the approval and why the agency proceeded without first holding a planned public hearing. In a statement, Maynard says the merger was approved after his staff and outside economists thoroughly reviewed the $37 billion transaction. State records show Maynard signed an order of approval Feb. 3. Economists hired to analyze the deal's competitive implications tell the newspaper that they're still working on reviewing the merger and submitting the full report. Maynard says the hearing was dropped because it would have taken more time and created an additional expense. Aetna announced last July an agreement to buy health care giant Humana.