ABSTRACT: Few trials have examined long-term outcomes of advance care planning (ACP) interventions. We examined the efficacy of an ACP intervention on preparation for end-of-life decision making for dialysis patients and surrogates and for surrogates' bereavement outcomes.A randomized trial compared an ACP intervention (Sharing Patient's Illness Representations to Increase Trust [SPIRIT]) to usual care alone, with blinded outcome assessments.420 participants (210 dyads of prevalent dialysis patients and their surrogates) from 20 dialysis centers.Every dyad received usual care. Those randomly assigned to SPIRIT had an in-depth ACP discussion at the center and a follow-up session at home 2 weeks later.preparation for end-of-life decision making, assessed for 12 months, included dyad congruence on goals of care at end of life, patient decisional conflict, surrogate decision-making confidence, and a composite of congruence and surrogate decision-making confidence.bereavement outcomes, assessed for 6 months, included anxiety, depression, and posttraumatic distress symptoms completed by surrogates after patient death.adjusting for time and baseline values, dyad congruence (OR, 1.89; 95% CI, 1.1-3.3), surrogate decision-making confidence (?=0.13; 95% CI, 0.01-0.24), and the composite (OR, 1.82; 95% CI, 1.0-3.2) were better in SPIRIT than controls, but patient decisional conflict did not differ between groups (?=-0.01; 95% CI, -0.12 to 0.10).45 patients died during the study. Surrogates in SPIRIT had less anxiety (?=-1.13; 95% CI, -2.23 to -0.03), depression (?=-2.54; 95% CI, -4.34 to -0.74), and posttraumatic distress (?=-5.75; 95% CI, -10.9 to -0.64) than controls.Study was conducted in a single US region.SPIRIT was associated with improvements in dyad preparation for end-of-life decision making and surrogate bereavement outcomes.