Patients referred for cardiac surgery are increasingly older, but chronological age does not always capture biological age. This study assessed frailty, as a functional parameter of biological age, as a predictor of mortality or prolonged institutional care. Functional measures of frailty and clinical preoperative data were collected for all cardiac surgery patients at a single center (2004 –2007). Based on the Katz Index of Activities of Daily Living, frailty was defined as any impairment in feeding, bathing, dressing, transferring, toileting, continence, or ambulation, or dementia. The impact of frailty on in-hospital mortality or institutional discharge (other hospital or nursing facility) was assessed with multivariate logistic regression. The interaction of frailty and age was examined, with non-frail patients age<70 as the referent group.
Results:
Of 3096 patients, 133 (4.3%) were frail. Frail patients were older, more likely to be female, have COPD, CHF, EF<40%, recent MI, pre-operative renal failure, cerebrovascular disease, greater acuity, and more complex operations (p<0.05). Frail patients experienced higher rates of mortality, sepsis, delirium, post-operative renal failure, and transfusion (p<0.001). A greater proportion of frail patients than non-frail patients (49% vs. 9%) were discharged to a setting other than home. In the risk-adjusted models, frailty was an independent predictor of mortality (OR 1.8, 95% CI 1.0 –3.2) or institutional discharge (OR 6.4, 95% CI 4.1–9.9). Furthermore, frail elderly (age≥70) patients had greater risk of institutional discharge (OR 22.7, CI 12.4 – 41.7) than frail younger patients (OR 6.5, CI 3.4 –12.5) or non-frail elderly patients (OR 3.5, CI 2.6 – 4.6). Similarly, frail elderly patients had greater risk of mortality (OR 4.0, CI 1.9 – 8.1) than frail younger patients (OR 1.9, CI 0.8 – 4.7) or non-frail elderly patients (OR 2.4, CI 1.7–3.5). Frailty was an independent predictor of in-hospital mortality and prolonged institutional care. Frailty combined with older age further discriminated those at highest risk. Special consideration should be given to the management of frail elderly patients who have surgical cardiac disease.
A 5-year-single-centre experience: outcome after continuous renal replacement therapy (CRRT) for acute renal failure following cardiac surgery
