Despite nationally recognized efforts to help residents avoid foreclosure, the state of Maryland has been slow to make mortgage payments more affordable for the struggling homeowners whose loans it owns. Gov. Martin O’Malley and his administration have pressed national loan servicers in recent years to work with homeowners rather than foreclose. But it wasn’t until four months ago that the state — which lends money to first-time homebuyers — designed a program to lower monthly mortgage payments to an amount that its borrowers in trouble could afford, The Baltimore Sun has learned. Only three such modifications have been approved so far.