Adherence to Guideline-Directed Medical Therapy and its Association with Re-Hospitalization and Mortality Following Coronary Artery Bypass Graft Surgery

Objectives: We investigated associations with re-hospitalization and long-term mortality, of cardio-thoracic surgeons` adherence to pharmacological guideline-directed medical therapy (GDMT) in discharge recommendations of elective coronary artery bypass graft (CABG) surgery patients.

Methods: In this longitudinal multicenter study, 1,131 patients who underwent elective CABG surgery in seven medical centers during 2004-2007 were interviewed in the hospital before surgery. Adherence of cardio-thoracic surgeons to GDMT was considered as prescribing medications from three families: antiplatelet therapy, beta-blockers and statins; and was determined from discharge letters. Patients were interviewed one-year after hospitalization to obtain information on re-hospitalizations and current medications. Mortality information was extracted from the Ministry of Internal Affairs registry and updated until March 2018.

Results: GDMT adherence was evident in the discharge recommendations of 638 patients (56.4%). A propensity score-adjusted multivariate logistic regression model showed a 41% lower 1-year risk of re-hospitalization\mortality among patients whose discharge recommendations reflected full physician adherence than among patients whose recommendations reflected partial adherence (OR=0.59, 95%CI: 0.45-0.78, p<0.001). Propensity score-adjusted Cox proportional hazard (PH) regression model showed 60% lower long-term mortality hazard among patients with cardio-thoracic surgeons` adherence to GDMT, compared to other patients (HR=0.40, 95% CI: 0.33-0.48, p<0.001). Cox survival analysis demonstrated a higher survival rate for exposed patients when considering cardio-thoracic surgeons` adherence to beta-blockers only or statins only (log-rank, p=0.01 and p≤0.001, accordingly).

Conclusions: The reference in CABG patients’ discharge recommendations to GDMT was associated with a lower 1-y readmissions/mortality and lower long-term mortality. Cardio-thoracic surgeons should adhere closely to preventive medication guidelines.

Keywords: Coronary artery bypass graft surgery, Guideline-directed medical therapy, Survival, Revascularization, Secondary prevention, Rehospitalization, Mortality, Multicenter, Adherence.