Outcomes of acute coronary syndrome in a large Canadian cohort: impact of chronic renal insufficiency, cardiac interventions, and anemia.
BACKGROUND
Chronic renal insufficiency (CRI) has been identified as an important risk factor for cardiac events. Studies in the United States reported decreased survival and decreased use of surgical and medical interventions after myocardial infarction in patients with CRI.


METHODS
We studied the impact of renal function on health outcomes in a Canadian cohort of consecutive patients admitted with acute coronary syndrome (ACS) between October 1997 and October 1999. The study design is an observational cohort of 5,549 adult patients who survived to discharge with a discharge diagnosis of ACS. Renal function is classified into 4 levels: (1) normal, glomerular filtration rate (GFR) greater than 80 mL/min/1.73 m2 (>1.33 mL/s); (2) mild CRI, GFR of 60 to 80 mL/min/1.73 m2 (1.00 to 1.33 mL/s); (3) moderate CRI, GFR of 30 to 59 mL/min/1.73 m2 (0.50 to 0.98 mL/s); and (4) severe CRI, GFR less than 30 mL/min/1.73 m2 (<0.50 mL/s). The primary outcome is death.


RESULTS
Advanced and moderate CRI independently predicted death (hazard ratio, 1.06; 95% confidence interval [CI], 1.01 to 1.12; and hazard ratio, 1.23; 95% CI, 1.18 to 1.29). Severe anemia (hemoglobin level < 9.0 g/dL [<90 g/L]) also was an independent risk factor for death (hazard ratio, 1.38; 95% CI, 1.18 to 1.61). Use of beta-blockers (hazard ratio, 0.91; 95% CI, 0.86 to 0.97), acetylsalicylic acid (hazard ratio, 0.90; 95% CI, 0.84 to 0.97), lipid-lowering therapy (hazard ratio, 0.84; 95% CI, 0.78 to 0.89), and medical thrombolysis (hazard ratio, 0.89; 95% CI, 0.81 to 0.97) were associated with reduced risk for death. Medical interventions with beta-blockers, acetylsalicylic acid, lipid-lowering therapy, and thrombolysis and surgical intervention were significantly less likely to be used in patients with CRI.


CONCLUSIONS
Despite universal access to health care, Canadian patients with CRI are more likely to die after a cardiac event and less likely to receive important interventions.
Keough-Ryan
Tammy M
TM
Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada. tammy.keough-ryan@cdha.nshealth.ca
Kiberd
Bryce A
BA
Dipchand
Christine S
CS
Cox
Jafna L
JL
Rose
Caren L
CL
Thompson
Kara J
KJ
Clase
Catherine M
CM
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000740:Anemia / Q000453:epidemiology* / Q000209:etiology; D000789:Angina, Unstable / Q000188:drug therapy / Q000453:epidemiology* / Q000601:surgery; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001241:Aspirin / Q000627:therapeutic use; D002317:Cardiovascular Agents / Q000627:therapeutic use; D015331:Cohort Studies; D015897:Comorbidity; D004363:Drug Utilization / Q000706:statistics & numerical data; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D005919:Glomerular Filtration Rate; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D000960:Hypolipidemic Agents / Q000627:therapeutic use; D007676:Kidney Failure, Chronic / Q000150:complications / Q000453:epidemiology*; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009026:Mortality; D009203:Myocardial Infarction / Q000188:drug therapy / Q000453:epidemiology* / Q000601:surgery; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D009674:Nova Scotia / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D016019:Survival Analysis; D015912:Thrombolytic Therapy; D016896:Treatment Outcome
D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D002317:Cardiovascular Agents; D005343:Fibrinolytic Agents; D000960:Hypolipidemic Agents; D001241:Aspirin