Impact of diabetes mellitus and renal insufficiency on 5-year mortality following coronary artery bypass graft surgery: a cohort study of 4869 UK patients.
OBJECTIVE
Diabetes mellitus (DM) and renal impairment (RI) are both independent predictors of mortality after coronary artery bypass graft surgery (CABG). The two conditions often coexist, yet the impact on long-term prognosis after CABG of each factor relative to the other and the two in combination is uncertain.


METHODS
We undertook a prospective cohort study of 4869 patients who underwent CABG between 2003 and 2007. The cohort was divided into four groups according to preoperative diabetic status and renal function: patients without either DM or RI (reference group), patients with DM alone, patients with RI alone and patients with both DM and RI. Clinical outcomes were compared between groups. Patients receiving renal replacement therapy were excluded. The primary outcome was 5-year all-cause mortality.


RESULTS
The crude 5-year all-cause mortality rate was 9.0% for patients in the reference group, 11.1% for patients with DM alone, 20.3% for patients with RI alone and 28.5% for patients with both DM and RI (P < 0.0001). Five-year survival adjusted for potential confounding factors was significantly worse for patients with DM (hazard ratio (HR) 1.30; 95% confidence interval (CI) 1.06-1.59), patients with RI (HR 1.32; 95% CI 1.08-1.61) and patients with both DM and RI (HR 2.04; 95% CI 1.65-2.53) when compared with patients with neither condition.


CONCLUSIONS
Preoperative DM and RI were important predictors of 5-year mortality after CABG. Patients with RI alone had a higher mortality rate than patients with DM alone, but this difference was largely accounted for by age and other comorbidities. The combination of DM and RI doubled the 5-year mortality rate after CABG independently of potential confounding factors.
Department of Cardiology, Barts Health NHS Trust, London, UK William Harvey Research Institute, Queen Mary and Westfield University, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Sean
S
Gallagher
Department of Cardiology, Barts Health NHS Trust, London, UK William Harvey Research Institute, Queen Mary and Westfield University, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Akhil
A
Kapur
Department of Cardiology, Barts Health NHS Trust, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Matthew J
MJ
Lovell
Department of Cardiology, Barts Health NHS Trust, London, UK William Harvey Research Institute, Queen Mary and Westfield University, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Dan A
DA
Jones
Cancer Research UK and UCL Cancer Trials Centre, University College London, London, UK.
Amy
A
Kirkwood
Department of Cardiology, Barts Health NHS Trust, London, UK.
Sevda
S
Hassan
Department of Cardiology, Barts Health NHS Trust, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
R Andrew
RA
Archbold
Department of Cardiology, Barts Health NHS Trust, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK.
Andrew
A
Wragg
William Harvey Research Institute, Queen Mary and Westfield University, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK Department of Cardiothoracic Surgery, Barts Health NHS Trust, London, UK.
Rakesh
R
Uppal
William Harvey Research Institute, Queen Mary and Westfield University, London, UK NIHR Cardiovascular Biomedical Research Unit, London Chest Hospital, London, UK Department of Nephrology, Barts Health NHS Trust, London, UK m.m.yaqoob@qmul.ac.uk.
Muhammad M
MM
Yaqoob
D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass / Q000401:mortality*; D003920:Diabetes Mellitus / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011446:Prospective Studies; D051437:Renal Insufficiency / Q000453:epidemiology / Q000401:mortality*; D006113:United Kingdom / Q000453:epidemiology
Coronary artery bypass graft surgery; Diabetes mellitus; Renal impairment