Objectives Studies that use national datasets to evaluate the management of older women with breast cancer are often constrained by a lack of information on patient fitness. This study constructed a frailty index for use with secondary care administrative records and evaluated its ability to improve models of treatment patterns and overall survival in women with breast cancer.
Design Retrospective cohort study.
Participants Women aged ≥50 years with oestrogen receptor (ER) positive early invasive breast cancer diagnosed between 2014 and 2017 in England.
Methods The secondary care administrative records frailty (SCARF) index was based on the cumulative deficit model of frailty, using International Statistical Classification of Diseases, Injuries and Causes of Death, 10th revision codes to define a set of deficits. The index was applied to administrative records that were linked to national cancer registry datasets. The ability of the SCARF index to improve the performance of regression models to explain observed variation in the rate of surgery and overall survival was evaluated using Harrell’s c-statistic and decision curve analysis. External validation was performed on a dataset of similar women diagnosed in Wales.
Results The SCARF index captured 32 deficits that cover functional impairment, geriatric syndromes, problems with nutrition, cognition and mood, and medical comorbidities. In the English dataset (n=67 925), the prevalence of frailty in women aged 50–69, 70–79 and ≥80 years was 15%, 28% and 47%, respectively. Adding a frailty measure to regression models containing age, tumour characteristics and comorbidity improved their ability to: (1) discriminate between whether a woman was likely to have surgery and (2) predict overall survival. Similar results were obtained when the models were applied to the Welsh cohort (n=4 230).
Conclusion The SCARF index provides a simple and consistent method to identify frailty in population level data and could help describe differences in breast cancer treatments and outcomes.
- geriatric medicine
- public health
- adult oncology
- statistics & research methods
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Contributors YJ: study concept and design, data acquisition management, statistical analysis and results interpretation and involvement in all stages of the manuscript development; MRG: study design, data acquisition and management, statistical analysis and results interpretation and involvement in all stages of manuscript development; DD and KH: study concept and design, data acquisition, interpretation of the results and involvement in all stages of manuscript development; KC: data acquisition, interpretation of the results and involvement in manuscript editing and review; JM: data acquisition and management, interpretation of the results and involvement in manuscript editing and review; CT: interpretation of the results and involvement in all stages of manuscript development; TR: study design, interpretation of the results and involvement in all stages of manuscript development; SS-KT and RP: interpretation of the results and involvement in manuscript editing and review; DAC: study concept and design, data acquisition and management, statistical analysis and results interpretation and involvement in all stages of the manuscript development. All authors have approved the final version of this article and agree to be accountable for all aspects of the work.
Funding This study was undertaken as part of the work by the National Audit of Breast Cancer in Older Patients. The Audit is commissioned by the Healthcare Quality Improvement Partnership (HQIP) as part of the National Clinical Audit and Patient Outcomes Programme and funded by NHS England and the Welsh Government (www.hqip.org.uk/national-programmes). The authors had full independence from the Healthcare Quality Improvement Partnership. The aim of National Audit of Breast Cancer in Older Patients (NABCOP) is to evaluate the care of older women with breast cancer in England and Wales, and support NHS providers to improve the quality of hospital care for these women. More information can be found at: www.nabcop.org.uk
Disclaimer Neither HQIP nor the funders had any involvement in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval The study is exempt from UK National Research Ethics Committee approval as it involved secondary analysis of an existing dataset of anonymised data. The NABCOP has approval for processing health care information under Section 251 (reference number: 16/CAG/0079) for all National Health Service (NHS) patients aged 50 years and over diagnosed with breast cancer in England and Wales. Data for this study are based on patient-level information collected by the NHS, as part of the care and support of patients with cancer. The data is collated, maintained and quality assured by the National Cancer Registration and Analysis Service, which is part of Public Health England.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available. No additional data available.