Benchmarking cancer outcomes in Europe: a scoping review of methodologies and case-mix adjustments

Benchmarking hospital outcomes is crucial for identifying inequities and improving cancer care. Meaningful comparisons require selecting relevant outcomes and adjusting for case-mix factors such as age, comorbidity, and stage. Without case-mix adjustment, hospitals may be unfairly assessed based on patient mix rather than care quality. No prior review has examined benchmarking practices in European cancer care. This scoping review addresses: (i) Which health outcomes are frequently benchmarked? (ii) What case-mix factors are commonly used for adjustment? (iii) Which statistical approaches are utilized? (iv) How are case-mix models developed and evaluated?

We conducted a systematic scoping review searching OVID MEDLINE, Web of Science, and EMBASE. Eligible studies focused on benchmarking populations with a cancer diagnosis, involved European hospitals, and evaluated health outcomes like survival. Abstract screening and full-text appraisal were done independently by two authors. Data were extracted into a pre-specified matrix, and results synthesized by research question.

After screening 4953 abstracts, 65 studies were included. Key gaps include a lack of validated case-mix models, under-representation of long-term outcomes, and a tendency to 'over-adjust' by including treatment factors in case-mix models, potentially obscuring true differences in performance. Regression modeling remains the gold standard for adjustment. A consensus is needed on reporting and evaluating case-mix models, akin to TRIPOD guidelines.

A shift toward standardized, validated benchmarking practices is essential to drive health care improvements. Only through rigorous methodologies, standardized reporting, and international collaboration can hospital benchmarking become a transformative tool for improving cancer care quality and patient outcomes.