Seniors with end-stage kidney disease who start dialysis are dying at higher rates than previously thought, according to new research from institutions that included Harvard Medical School and the Icahn School of Medicine at Mount Sinai.

More than half of adults older than 65 years who started dialysis died within a year of beginning treatment, while close to 1 in 4 died within a month. Those rates are almost twice as high as statistics commonly reported from government data, researchers said.

Results appeared April 22 in JAMA Internal Medicine.