# Estimating post-operative complication rates in patients with primary brain tumours from routine administrative data: A national cohort study

## TL;DR

This study improves the ability to track post-surgery complications in brain tumor patients using national data, finding that complications are more common than previously thought and linked to worse outcomes.

## Contribution

The study introduces a novel ICL list of complications tailored for brain tumor surgery, enabling national-level analysis of post-operative outcomes.

## Key findings

- 30-day readmission after surgery was 12.7% and 30-day mortality was 2.3%.
- The ICL list identified 11.3% of patients with complications, compared to 2.0% with the OECD-defined PSI list.
- 30-day mortality was 6.5% in patients with complications versus 1.8% in those without.

## Abstract

Neurosurgery is an important element of brain tumour treatment but carries with it the risk of complications. Previous work has defined a narrow set of general post-operative complications which are used as Patient Safety Indicators (PSIs), but these are not brain tumour specific and do not capture the full range of complications. As a result, there is no way of measuring post-operative complications in neurosurgery at a national level.

We conducted a retrospective, observational cohort study using a comprehensive national administrative dataset from England on adult brain or spinal tumour patients to better define post-operative complications. We generated and validated a new list of post-operative complications – ICL list. The ICL list contains codes selected specifically from our Gliocova dataset combined with general OECD-defined PSI list. The ICL list is novel as it can assess brain tumour patient complications using an administrative dataset at a national level and captures more specific brain tumour related complications.

In our study, 30-day readmission after surgery was 12.7% and 30-day mortality was 2.3%. The ICL list of complications identified many more patients with complications (N = 3,274 (11.3%)) compared to OECD-defined PSI list (N = 568 (2.0%)) without reducing model performance. 30-day mortality was 6.5% in those with complications and 1.8% in those without.

We have identified a much wider set of complications than the OECD-defined PSIs and shown that patients developing these have worse outcomes than those without complications. This enables us to estimate the risk of post-operative complications in brain tumour patients using national administrative data. It forms the basis for planned further work, allowing us to explore the predictors of and consequences of post-operative complications.