Cardiovascular disease is the commonest complication of kidney disease. The risk of cardiovascular disease increases as estimated glomerular filtration rate (eGFR) declines and is highest in patients with advanced chronic kidney disease (CKD) on dialysis or with a kidney transplant - termed 'kidney failure'. Despite this, patients with kidney disease have been excluded from most cardiovascular trials over the last three decades. Given this systematic disenfranchisement of patients with kidney disease, our understanding of the diagnosis, incidence, treatment, and outcomes of cardiovascular disease in these patients is limited. My aim was to use large-scale, contemporaneous regional and national routinely-collected, linked Scottish healthcare data to illustrate, update, and address CKD-related disparities in the diagnosis, treatment, outcomes, and temporal trends of cardiovascular disease in patients with kidney disease. First, I performed a pre-specified secondary analysis of a stepped-wedge, cluster-randomised controlled trial to evaluate the implementation of a high-sensitivity cardiac troponin I assay on the diagnosis, management, and outcomes of patients with and without kidney impairment identified as having myocardial injury or infarction. In 46,927 consecutive patients presenting to hospital with suspected acute coronary syndrome, 19% had kidney impairment. As kidney function declined, the frequency of elevated cardiac troponin concentrations increased six-fold, but the proportion diagnosed with type 1 myocardial infarction halved. Implementation of high-sensitivity cardiac troponin testing increased the diagnosis of type 1 myocardial infarction in both patients with and without kidney impairment. Following implementation, rates of coronary angiography, revascularisation and the prescription of evidencebased treatments increased in patients with normal kidney function, but not in patients with kidney impairment. Despite the identification of more patients at risk, rates of myocardial infarction or cardiovascular death at one year were unchanged in patients with kidney impairment following implementation of high-sensitivity cardiac troponin testing. Second, I performed a retrospective, national data-linkage study to assess temporal trends in the incidence, treatment and outcomes myocardial infarction and stroke in patients with kidney failure in Scotland over the past 20 years. Amongst 16,072 patients with kidney failure, there were 1,992 and 996 incident episodes of myocardial infarction and stroke between 1996 and 2016. During this period, the incidence of myocardial infarction and stroke decreased by ~1.5-fold in patients with kidney failure. When compared with the general population, patients with kidney failure had a ~5 times higher overall incidence of myocardial infarction and a ~3 times higher overall incidence of stroke. Since 2009, there has also been a ~3-fold increase in the prescription of antiplatelet therapy following incident stroke and a ~1.5-fold increase in the prescription of dual antiplatelet therapy following incident myocardial infarction. Finally, although 1-year cardiovascular case fatality has improved substantially following myocardial infarction and stroke in patients with kidney failure over the past 20 years in both sexes and across all kidney replacement therapy modalities, overall outcomes for these patients remain poor. Third, I performed a nationwide data-linkage study comparing the clinical characteristics, microbiology, and long-term outcomes of infective endocarditis in patients with and without kidney failure in Scotland over the past three decades. One-fifth of patients with kidney failure died within 30 days of their incident infective endocarditis hospitalisation, half died within one year, and two-thirds within three years. Compared to those without kidney failure, patients with kidney failure were twice as likely to die within one year of hospitalisation and more than three times as likely to die within three years. Fourth, I investigated how infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) modified existing short- and medium-term cardiovascular risk in ~37,000 patients with and without CKD. In patients with CKD, those with COVID-19 had a higher risk of cardiovascular and all-cause death than those without COVID-19 throughout follow-up, but especially within 30 days of SARS-CoV-2 testing. During this early period, patients with CKD and COVID-19 had a more than two-fold increased risk of cardiovascular death - and a more than four-fold increased risk of all-cause death - than patients with CKD who tested negative. Compared to patients without CKD, those with CKD were also more likely to test positive. Following a positive test, patients with CKD had higher rates of cardiovascular complications - including hospitalisations and cardiovascular death - than those without CKD. Moreover, the risks of cardiovascular, COVID-19-related, and all-cause death increased as kidney function declined. My findings highlight the power and potential of contemporaneous routinelycollected, linked healthcare data to define and address established CKDrelated disparities in cardiovascular disease and outcomes. Moreover, my results will provide an evidence base for public health policy and inform planning of healthcare resource allocation for all patients with kidney disease. My future work will focus on using high-fidelity routinely-collected data to improve the cardiovascular risk stratification of patients with kidney failure listed for kidney transplantation and to comprehensively define how age, sex, and socioeconomic status interact to influence the development, treatment, progression, and outcomes of cardiovascular and kidney disease.