Mercy will be the 58th rural hospital to close in the United States since 2010, according to one research program, and many more could soon join the list because of declining reimbursements, growing regulatory burdens and shrinking rural populations that result in an older, sicker pool of patients. The closings have accelerated over the last few years and have hit more midsize hospitals like Mercy, which was licensed for 75 beds, than smaller “critical access” hospitals, which are reimbursed at a higher rate by Medicare.