Review question/objective

The objective of this review is to describe and compare the predictive value of existing frailty indices for postoperative morbidity and mortality.

More specifically, the review question is: what postoperative outcomes can be predicted by frailty indices in elderly patients?

Background

Over the next 30 years, the Canadian healthcare system will treat an unprecedented number of older adults, many with multiple chronic diseases. Internationally, the World Health Organization (WHO) is developing strategic recommendations in moving forward on addressing current and emerging frailty and disability in aging populations. Frailty is a state of reduced physiologic reserve associated with increased susceptibility to disability.1 It is a global phenotype introducing vulnerability which limits a person's ability to respond to stressors.1 Frailty is a delicate state of health that makes people vulnerable to illness and injury because they lack the strength to withstand physical and emotional stress.2 They possess a diminished ability to fight back to health. As people age, they may lose muscle mass and bone strength. They may feel less stable on their feet and begin to move more slowly. They may find that shopping and housework are getting more difficult. As their ability to think and remember decreases, they may find it harder to keep track of details of their daily lives.

When a frail person is injured or sick, he is slow to recover and may never regain his previous level of health. As more health problems develop over time, the person requires more help from others with tasks of daily living, such as cooking, shopping and banking. Eventually, he or she may need help with personal care, such as bathing or dressing. During hospitalization or following medical procedures, frail patients may suffer complications such as delirium and functional decline. Delirium is a state of confusion that, once triggered, may not fully resolve. Functional decline is the loss of the ability to perform tasks that the person could previously perform, resulting in dependency on others. It may mean being admitted to a long-term care institution. These are very significant potential complications to an older individual. They may be more frightening than death.

Despite significant frailty, many individuals will be considered for and will ask for highly aggressive care that has uncertain chances of success and may well result in prolonged disability and suffering. Indices exist which incorporate cognition, mobility, function and co-morbid diseases to determine a frailty score. Low and high scores correlate with fitness and severe frailty respectively, which effectively estimate important outcomes3, such a survival/mortality, morbidity and institutionalization.

Multiple frailty assessment tools exist which show predictive validity for poor health outcomes: the Frail Elderly Functional Assessment Questionnaire (FEFA), the Clinical Global Impression of Change in Physical Frailty (CGIC-PF), the Frailty Index-Comprehensive Geriatric Assessment, the Clinical Frailty Scale and the Frailty Phenotype.4,5 In quantifying risk in relation to the extent of deficit accumulation, a frailty score lends predictive validity to the notion that every frail adult will have a unique collection of health deficits and symptoms that contribute to frailty.5 Unfortunately, the nature of modern healthcare means that treatment regimens to improve one health condition might well be to the detriment of another.6

Recent incorporation of the frailty score in the perioperative context has shown its predictive value in estimating risk and outcomes postoperatively. Frailty has been identified as an independent risk factor for in-hospital mortality and morbidity, including delirium, functional decline, and prolonged ventilation, increased length of stay, as well as discharge to institutional care.7,8 Rockwood and colleagues showed that when the Clinical Frailty Scale was applied to 2305 patients, with a mean age above 80, each one-category increment of the scale significantly increased the medium-term risks of death and entry into an institution.6 Similarly, frailty had an independent relationship with the occurrence of one or more postoperative complications. In a prospective cohort study of patients undergoing elective colorectal and cardiac operations, hospital stay and 30-day readmission rates were significantly higher in the frail group, compared to the non-frail group.9 Frailty in a patient has consistently been shown to be an independent risk factor in the development of adverse postoperative outcomes, such as mortality, morbidity, discharge to institution and increased hospital length of stay (LOS).10

A 2014 Alberta study looked at how frail patients lived and functioned independently after a stay in the Intensive Care Unit (ICU). Even though most people survived their operations and ICU stay, frailty was associated with a mortality of 48% versus 25% for non-frail patients 12 months later. Only 15% of all the frail patients who lived independently prior to illness were still living independently in follow-up.11

Globally, health policy and practice is changing to address frailty. The World Health Organization (WHO) expert group, in collaboration with the International Association of Gerontology and Geriatrics, is working on recommendations on how to develop and implement interventions in clinical practice to target frail people.12 As well, the 10/66 Dementia Research Group, King's College, London, and the Public Health Foundation for India is working with the WHO to develop guidance and a new intervention package for frail, dependent older people in resource-poor settings.

The power of a frailty score in the preoperative period to predict postoperative outcomes may help patients make informed decisions about their care, to best preserve their quality of life, which may or may not include continuing with surgery. If surgery is decided on, additional supports (geriatric multidisciplinary team, intensive care unit, alternate level of care, etc.) may be anticipated, and this in turn can help the health care team and policy makers plan for resource allocation.

The purpose of this review is to identify and compare validated frailty scores which may be used preoperatively to risk stratify patients to predict postoperative outcomes. A search of the JBI Library of Systematic Reviews and Implementation Reports, Cochrane Database of Systematic Reviews, Epistemonikos, Medline and CINAHL found no existing systematic review on this topic with this research question. There was one article that was limited in its scope, answering a different research question that was a narrative review without synthesis.10

Inclusion criteria

Types of participants

Studies that include surgical patients, from any speciality, over the age of 65, and of both sexes will be considered.

Types of intervention(s)/phenomena of interest

Studies that evaluate or employ validated frailty indices or scales in the context of perioperative care will be considered. This list is not exhaustive but will include the following indices: the Frail Elderly Functional Assessment Questionnaire (FEFA), the Clinical Global Impression of Change in Physical Frailty (CGIC-PF), the Frailty Index-Comprehensive Geriatric Assessment, the Clinical Frailty Scale and the Frailty Phenotype.

Types of outcomes

Only studies that include the following outcome measures will be considered: 1) length of in-patient hospital stay; 2) postoperative complications of all types; 3) discharge to an alternate level of care (ALC) facility or status; and 4) mortality. Some specific examples of postoperative complications include: ICU stay, prolonged mechanical ventilation and respiratory failure.

Types of studies

This review will consider both experimental and non-experimental study designs including randomized controlled trials, non-randomized controlled trials, quasi-experimental, before and after studies, prospective and retrospective cohort studies, case control studies and analytical cross sectional studies.

This review will also consider descriptive epidemiological study designs, including case series, individual case reports and descriptive cross sectional studies.

Search strategy

The search strategy aims to find both published and unpublished studies. A three-step search strategy will be utilized in this review. An initial limited search of MEDLINE and CINAHL will be undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe article. A second search using all identified keywords and index terms will then be undertaken across all included databases. Thirdly, the reference list of all identified reports and articles will be searched for additional studies. Studies published in English and studies published after 1990 will be considered for inclusion in this review. The concept of frailty and the development of frailty scales/scores were only introduced in the last two decades. Our preliminary search of the literature yielded only articles published after 1990.

The databases to be searched include:

EMBASE, MEDLINE, CINAHL, PsycINFO, and COCHRANE.

The search for unpublished studies will include: Dissertations and Abstracts.

Initial keywords to be used will be: frailty, frail, frailty index, postoperative complication, preoperative evaluation, prognosis

Assessment of methodological quality

Quantitative papers selected for retrieval will be assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI) (Appendix I). Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer (MM).

Data extraction

Quantitative data will be extracted from papers included in the review using the standardized data extraction tool from JBI-MAStARI (Appendix II). The data extracted will include specific details about the preoperative frailty assessment, populations, study methods and outcomes of significance to the review question and specific objectives. Authors of primary studies will be contacted as necessary to address any clarity issues that are present in the data.

Data synthesis

Results from included studies will, where possible, be pooled in statistical meta-analysis using JBI-MAStARI. All results will be subject to double data entry. Effect sizes expressed as odds ratio (for categorical data) and weighted mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-square and also explored using subgroup analyses based on the different quantitative study designs included in this review and may include analyses between genders and surgical specialties if possible. Where statistical pooling is not possible the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.

Conflicts of interest

The authors declare that there are no known conflicts of interest.

References