Abstract Background and Aims Mortality within the first year after dialysis start is estimated to be 20-30%, and it is mostly due to cardiovascular disease. Prognostic assessment after starting hemodialysis is challenging. Clark et al. developed the Recovery and Death Outcome risk score, which accurately predicted the likelihood of renal recovery to dialysis independence and of death within 1 year after discharge from in-hospital dialysis initiation. These models can be used at discharge or soon after patients start outpatient dialysis. We aimed to validate the Death Outcome risk score to predict one-year mortality after dialysis start in our population. Method .Retrospective analysis of hospitalized patients who initiated hemodialysis in a tertiary care hospital (Unidade Local de Saúde Santa Maria), from January 1st of 2016 to December 31st of 2019, and were discharged to outpatient dialysis. The risk of death within one year of discharge was calculated according to the ReDO score. We evaluated all-cause mortality within one year of hospital discharge. We classified patients into death outcome risk groups (labeled D1 to D4) according to the ReDO predictive score. Cox regression method was used to determine if the risk score was predictive of mortality within the first year after discharge. The discriminatory ability for the ReDO score to predict mortality was determined using the receiver operating characteristic (ROC) curve. Results 369 patients were included, with a mean age of 71.1 ± 14.3 years. The majority were male (59.9%, n = 221) and 87% were Caucasian (n = 321). The median Charlson score was 7 ± 3. The mortality rate within one year after discharge was 22.2% (n = 82). The one-year survival was significantly lower in patients with the highest probability of death (D4 = 61.3% vs. D3 = 67.6% vs. D2 = 81.3% vs. D4 = 97.3%, p < 0.001). The ReDO Death score accurately predicted the one-year risk of mortality, with an area under the ROC curve of 0.741, [95% CI (0.687–0.794), p < 0.001] (Fig. 1). The optimal REDO Death risk cut-off was >30%, with a hazard ratio of 6.57 [95% CI (3.48–12.2), p < 0.001] for one year risk of death, with a sensitivity of 78.0% and specificity of 60.6%. Conclusion We validated the ReDO score for 1-year mortality prediction after starting hemodialysis during hospitalization in a Portuguese population. This score can be used as a tool to inform goals of care discussion at the time of transition to out-of-hospital care, involving the in-hospital nephrology care team, the patient, and, if applicable, the future care team, as it can enlighten clinical decisions and, in some cases, lead to better end-of-life planning.