We examined trends in per capita spending for Medicare beneficiaries ages sixty-five and older in the United States in the period 1999-2012 to determine why spending growth has been declining since around 2005. Decomposing spending by condition, we found that half of the spending slowdown was attributable to slower growth in spending for cardiovascular diseases. Spending growth also slowed for dementia, renal and genitourinary diseases, and aftercare for people with acute illnesses. Using estimates from the medical literature of the impact of pharmaceuticals on acute disease, we found that roughly half of the reduction in major cardiovascular events was attributable to medications controlling cardiovascular risk factors. Despite this substantial cost-saving improvement in cardiovascular health, additional opportunities remain to lower spending through disease prevention and control.