The letter and the fundraising event were for the hospital’s centennial celebration which was in 2009.
Here’s a link to the Kapi’olani Medical Center Centennial Celebration Letter, scroll down to page six to read it: http://www.wnd.com/files/InspireMagazineSpring2009.pdf
Kapi’olani posted a copy of Obama’s letter on its website and used it for fundraising. After WorldnetDaily questioned aspects of the letter’s authenticity, the hospital removed it from its website and has kept it hidden from public view ever since.