Risk of coronary events in people with chronic kidney disease compared with those with diabetes: a population-level cohort study.

BACKGROUND: Diabetes is regarded as a coronary heart disease risk equivalent-ie, people with the disorder have a risk of coronary events similar to those with previous myocardial infarction. We assessed whether chronic kidney disease should be regarded as a coronary heart disease risk equivalent.

METHODS: We studied a population-based cohort with measures of estimated glomerular filtration rate (eGFR) and proteinuria from Alberta, Canada. We used validated algorithms based on hospital admission and medical-claim data to classify participants with baseline history of myocardial infarction or diabetes and to ascertain which patients were admitted to hospital for myocardial infarction during follow-up (the primary outcome). For our primary analysis, we defined baseline chronic kidney disease as eGFR 15-59·9 mL/min per 1·73 m(2) (stage 3 or 4 disease). We used Poisson regression to calculate unadjusted rates and relative rates of myocardial infarction during follow-up for five risk groups: people with previous myocardial infarction (with or without diabetes or chronic kidney disease), and (of those without previous myocardial infarction), four mutually exclusive groups defined by the presence or absence of diabetes and chronic kidney disease.

FINDINGS: During a median follow-up of 48 months (IQR 25-65), 11,340 of 1,268,029 participants (1%) were admitted to hospital with myocardial infarction. The unadjusted rate of myocardial infarction was highest in people with previous myocardial infarction (18·5 per 1000 person-years, 95% CI 17·4-19·8). In people without previous myocardial infarction, the rate of myocardial infarction was lower in those with diabetes (without chronic kidney disease) than in those with chronic kidney disease (without diabetes; 5·4 per 1000 person-years, 5·2-5·7, vs 6·9 per 1000 person-years, 6·6-7·2; p<0·0001). The rate of incident myocardial infarction in people with diabetes was substantially lower than for those with chronic kidney disease when defined by eGFR of less than 45 mL/min per 1·73 m(2) and severely increased proteinuria (6·6 per 1000 person-years, 6·4-6·9 vs 12·4 per 1000 person-years, 9·7-15·9).

INTERPRETATION: Our findings suggest that chronic kidney disease could be added to the list of criteria defining people at highest risk of future coronary events.

FUNDING: Alberta Heritage Foundation for Medical Research.