Objectives: Early-onset Alzheimer's disease (EOAD), defined as onset of AD before the age of 65 years, is less common than the late-onset type, and little is known about the factors affecting disease progression. The aim of the study was to investigate factors influencing disease progression in people with EOAD.Design: Retrospective cohort study.Setting and Participants: People with EOAD who were assessed and attended the specialist memory service at a university teaching hospital in a European setting, between 2000 and 2010.Measures: Sociodemographic details and clinical and cognitive assessments at initial assessment were used as potential predictors of change in clinical status and outcome at final follow-up within the memory service.Results: Of the 101 people diagnosed with EOAD during this period, 96 patients were followed up (53 women; aged 59 +/- 4.9 years; mean follow-up 36.3 +/- 29.12 months). Patients were classified as Stable (n = 25) if continued within the memory service or discharged to primary care, and those transferred to other specialist services (n = 66) for further inputs, institutional care (n = 4), or died (n = 1) were classified as Worseners (n = 71). Lower education (P = .008), lower Cambridge Cognition Examination scores (P = .049), and presence of family history of dementia [P = .012, chi(2) (1) = 8.84] was associated with worse change in clinical status. Furthermore, cognitive deficits such as lower scores on comprehension, recent memory, and executive functions were found to predict a worse clinical outcome.Conclusions and Implications: Identification of predictors of faster disease progression has significant clinical benefit, allowing clinicians to estimate prognosis and plan patient care accordingly. (C) 2020 AMDA - The Society for Post-Acute and Long-Term Care Medicine.