April 15 (Bloomberg) — Regardless of what Americans think about Obamacare, reining in health care costs is winning the support of investors in U.S. Treasuries.

After doubling in the past two decades, medical expenses rose less last year than at any time since Harry S. Truman was president in 1949, helped by Medicare reimbursement cuts. The rollout of President Barack Obama's signature 2010 law will hold down consumer prices for years to come as millions of Americans obtain coverage under the Patient Protection and Affordable Care Act, BNP Paribas SA and Credit Suisse Group AG said.

Less inflation, which boosts the purchasing power of fixed- rate payments, may help attract buyers to Treasuries as the economy strengthens and the Federal Reserve pares its own bond buying. While yields have fallen this year, the compensation 10- year notes provide after inflation is close to the highest in five years. Excluding food and energy, health care accounted for about a third of the slowdown in consumer prices, which rose 1.1 percent in the past year from 2 percent in the prior 12 months.