Frailty indexes in perioperative and critical care: A systematic review

Background/objectives: Frail patients are increasingly presenting for both perioperative and intensive care, highlighting the need for simple, valid and scaleable frailty measurement. Frailty indexes comprehensively assess a range of deficits in health, and can incorporate routinely collected data. The purpose of this systematic review was to evaluate the effect of frailty indexes on surgical and intensive care risk stratification and patient outcomes (mortality, complications, length of stay, and discharge location). Methods: A prospectively registered systematic review was performed. MEDLINE, EMBASE, and CINAHL were searched to identify studies enrolling adult surgical or intensive care patients which used a frailty index. Included studies were those published subsequent to 1990, of any study design, which utilised a frailty index consisting of >= 30 health deficits. Primary outcome was mortality; secondary outcomes were complications, length of stay (LOS) and discharge location. Study and frailty index quality were critically appraised by three independent reviewers, with findings narratively described. Results: 2026 articles were screened, from which nine prospective and four retrospective cohort studies (enrolling 2539 patients) were included. Frailty prevalence ranged between 19-62%; frailty indexes identified patients at risk of increased death [mortality rates ranging between 1.9-73.1%; reported odds ratios (ORs) for death ranging between 1.76-3.09 for frail vs. non-frail patients], surgical complications (ORs = 1.67-4.4), increased LOS, and discharge to residential care (ORs = 1.9-3.64). The term "frailty index" was found to be applied to a number of alternative measurement scales. Conclusion: Frail patients are at significantly increased risk in critical illness and the perioperative period. Better standardisation of frailty indexes is recommended.