Chronic obstructive pulmonary disease (COPD), is associated with an increased risk of myocardial infarction (MI), and additionally, cardiovascular disease is responsible for up to 1/3 of deaths in people with COPD. This may be attributable to the fact people with COPD are managed differently and have higher mortality after MI compared to people without COPD. One reason for the differences in management may be that prognostic risk scores after MI do not perform well in those with COPD. Another reason may be that acute exacerbations of COPD (AECOPD) are thought to be associated with a transiently increased risk of MI. The aims of this thesis are to: 1)systematically review the evidence for an increased risk of MI associated with COPD and AECOPD, and increased risk of death following MI for those with COPD; 2) investigate the potential contribution of differences in management after MI on differences in mortality; 3) investigate the performance of prognostic risk scores after MI for those with COPD; 4) validate the recording of AECOPD in UK electronic healthcare records (EHR); 5) investigate the recording of hospitalisations for AECOPD in UK primary and secondary care EHR; and 6) to conduct a self-controlled case series to investigate the risk of MI associated with AECOPD. This work showed an increased risk of MI associated with COPD independent of smoking, and evidence for an increased risk of death following hospital discharge for people with compared to those without COPD. This work demonstrated that differences in recognition and management of MI for those with COPD may explain some of the higher risk of death for COPD patients following MI. Additionally, the GRACE score (commonly used for risk stratification following MI) does not perform as well for COPD patients and may explain some of the differences in management. A validated algorithm was developed for identifying AECOPD both in primary care and resulting in hospital admission in electronic health records. Finally, using a self-controlled case series analysis, data showed that AECOPD is associated with increased risk of MI for approximately four weeks following AECOPD onset, and that the risk is modified by important patient characteristics.