Background The natural history of Coronavirus Disease MESHD 2019 (COVID-19) has yet to be fully described, with most previous reports focusing on hospitalised patients. Using linked patient-level data, we set out to describe the associations between age TRANS, gender TRANS, and comorbidities and the risk of outpatient COVID-19 diagnosis, hospitalisation, and/or related mortality. Methods A population-based cohort study including all individuals registered in Information System for Research in Primary Care (SIDIAP). SIDIAP includes primary care records covering > 80% of the population of Catalonia, Spain, and was linked to region-wide testing, hospital and mortality records. Outpatient diagnoses of COVID-19, hospitalisations with COVID-19, and deaths MESHD with COVID-19 were identified between 1st March and 6th May 2020. A multi-state model was used, with cause-specific Cox survival models estimated for each transition. Findings A total of 5,664,652 individuals were included. Of these, 109,367 had an outpatient diagnosis of COVID-19, 18,019 were hospitalised with COVID-19, and 5,585 died after either being diagnosed or hospitalised with COVID-19. Half of those who died were not admitted to hospital prior to their death MESHD. Risk of a diagnosis with COVID-19 peaked first in middle- age TRANS and then again for oldest ages TRANS, risk for hospitalisation after diagnosis peaked around 70 years old, with all other risks highest at oldest ages TRANS. Male TRANS gender TRANS was associated with an increased risk for all outcomes other than outpatient diagnosis. The comorbidities studied (autoimmune condition, chronic kidney disease HP kidney disease MESHD, chronic obstructive pulmonary disease MESHD chronic obstructive pulmonary disease HP, dementia MESHD dementia HP, heart disease MESHD, hyperlipidemia MESHD hyperlipidemia HP, hypertension, malignant MESHD hypertension HP neoplasm MESHD neoplasm HP, obesity MESHD obesity HP, and type 2 diabetes) were all associated with worse outcomes. Interpretation There is a continued need to protect those at high risk of poor outcomes, particularly the elderly TRANS, from COVID-19 and provide appropriate care for those who develop symptomatic disease MESHD. While risks of hospitalisation and death MESHD are lower for younger populations, there is a need to limit their role in community transmission TRANS. These findings should inform public health strategies, including future vaccination campaigns.