Burden and causes for hospitalizations following coronary artery bypass grafting: a nationwide cohort study†

Hospitalizations are a major burden for both patients and society and are potentially preventable. However, data on the burden and causes for hospitalizations after coronary artery bypass grafting (CABG) are sparse. We examined hospitalizations within 1 year after CABG and associated factors.

Using the Danish nationwide registries, we identified 36 475 patients who underwent first-time isolated CABG (1998-2014) and were discharged alive. Subsequent hospitalizations were classified as cardiovascular or non-cardiovascular according to discharge diagnosis codes. Factors associated with any hospitalization were identified using the Cox regression.

Thirty-day hospitalization risks for all-cause, cardiovascular and non-cardiovascular reasons were 16.7%, 12.4% and 4.2%, respectively. The corresponding 1-year hospitalization risks were 40.2%, 28.6% and 11.5%. Among patients who survived the first year, 7877 (22.1%) patients were admitted once, 3198 (9.0%) patients were admitted twice and 2844 (8.0%) patients were admitted 3 or more times within the first year. Ischaemic heart disease (15.6%), angina pectoris (9.8%), atrial fibrillation (AF) (8.7%) and heart failure (8.0%) were the most frequent reasons for hospitalization. Factors associated with any hospitalization were lower income level, a history of stroke, heart failure, AF, diabetes, malignancy, chronic renal failure, chronic obstructive pulmonary disease, longer length of stay, postoperative AF and stroke.

Within 1-year post-CABG, 40% of patients had at least 1 hospitalization, and approximately 70% of all hospitalizations were attributed to a cardiovascular cause. Lower socioeconomic status, preoperative comorbidities, postoperative complications during index admission and a longer length of stay were associated with hospitalization.