Fewer U.S. physicians are seeing Medicaid patients. That is due, in large part, to a lack of funds, a new study finds.

The proportion of physicians seeing Medicaid beneficiaries slipped by about 1.7 percentage points over the past decade, according to the Center for Studying Health System Change. Roughly 15% of physicians said they did not have any Medicaid revenue for the last half of 2004 and the first half of 2005. That compared with approximately 13% during the same periods in 1996 and 1997.

In 2004-2005, about 20% of physicians declined to accept new Medicaid patients. Most blamed inadequate reimbursement.