Trust results

How is data completeness defined?

Data completeness is defined as the proportion of patients with complete data for the variables age, sex, ASA grade, pathological TNM stage (tumour, node, metastasis staging) and site of cancer. This is because these seven variables are used for risk-adjustment. Mode of admission and number of co-morbidities are also used in the risk-adjustment model but are collected from HES/PEDW data and so are not included in the assessment of data completeness. Data completeness is only assessed in patients who underwent major resection because only in these patients could all seven data items be expected to be complete.

How is length of hospital stay defined?

Length of hospital stay was defined as the number of days between date of surgical procedure as recorded in HES/PEDW, and either discharge or death. The audit uses length of stay >5 days as an outcome because it is in keeping with the median length of stay reported in randomised trials of enhanced recovery programmes and large cohort studies. It reflects good quality post operative care and complication free recovery.

J Clin Oncol. 2014 Jun 10;32(17):1804-11. doi: 10.1200/JCO.2013.54.3694. Epub 2014 May 5
Ann Surg. 2015 Jun;261(6):1153-9. doi: 10.1097/SLA.0000000000001029.

How is 90-day mortality defined?

90-day mortality is defined as death from any cause, according to ONS, within 90 days of major resection. Date of major resection is according to NBOCA.

NBOCA reports 90-day rather than 30-day mortality. From a patient’s perspective the risk of post-operative death at 3 months is just as significant an outcome as death within 1 month of surgery. Post-operative death at 3 months captures those deaths that occur after prolonged critical care support which is now a much more common feature of colorectal cancer resection and adds significantly to the procedure-associated death rate. A previous study showed that the vast majority of deaths occurring within 90 days of surgery were as a result of complications of the surgery [Archives of Surgery 2009; 144: 1021-1027].

How is 30-day unplanned readmissions defined?

30-day unplanned readmission is defined as an emergency admission to any hospital for any cause within 30 days of surgery, according to HES. Date of surgery is taken from HES. Emergency admission is defined in HES as admission via Accident and Emergency services, or emergency admission via general practitioner, Bed Bureau, or consultant outpatient clinic.

How is 30-day unplanned return to theatre defined?

30-day unplanned return to theatre is defined as the presence of any of a set of OPCS codes for reoperation in HES/PEDW within 30 days of surgery. The majority of OPCS codes are only valid on days 1-30 after surgery to avoid classifying procedures which were part of the original major surgery as an unplanned reoperation. See Methodology Supplement 2021 for a full list of OPCS codes for reoperation.

How is 18 month unclosed ileostomy defined?

Rectal cancer patients undergoing an anterior resection, according to NBOCA, and who receive an ileostomy within 30 days of their procedure, according to HES/PEDW, are included in the denominator. Patients without a procedure code for stoma reversal (OPCS code G753 or H154) within 18-months of surgery, according to HES/PEDW, are assumed to have an unclosed ileostomy at 18 months (the numerator).

A patient with an ileostomy who dies within 18 months before having it reversed is included in the numerator and the denominator of the 18-month unclosed ileostomy rate. Dying before a stoma is reversed is a poor outcome which, it was felt, should not be excluded from the estimate. The proportion of rectal cancer patients with a “temporary” stoma who die within 18 months of surgery before having their stoma reversed is relatively small and therefore the inclusion of these patients has only a small effect on the 18-month unclosed ileostomy rate.

How is 2 year mortality rate defined?

The observed 2-year mortality rate is the number of patients who died within 2 years divided by the sum of the amount of time each patient is followed for. For example, for patients who survived for the 2 years their follow-up time is 2 years but for a patient who died at 3 months their follow-up time is 3 months.

2-year mortality rate is not the number of patients who died within 2 years divided by the number of patients included in the estimate; it also takes into account when each patient died. Taking into account the amount of follow-up time means that the estimate compares not just the proportion of patients who died within 2 years but also how quickly they died.

Consider as an example two units in which the same proportion of patients die within 2 years. In this example the unit in which patients die earlier will have a higher 2-year mortality rate. This standard method for estimating longer-term mortality rates is called ‘Survival Analysis’.

How has the COVID-19 pandemic impacted NBOCA reporting?

Data on colorectal cancer outcomes during COVID-19 and the recovery phase have not been used for benchmarking of providers.

The patient cohort included in the 2020 annual report pre-dated the pandemic and so the results within the 2020 annual report were unaffected. However, due to pressures on providers during the initial phase of the pandemic we were unable to do our usual data checking process, and this is why there is more incomplete data for this reporting period than we would usually expect.

The 2021 report included patients diagnosed primarily between 01 April 2019 and 31 March 2020. Only major resections up to 31 March 2020 were included in order to avoid the impact of the pandemic. Patients diagnosed before 31 March 2020 and undergoing major resection after this date were included in the 2022 report.

The 2022 report included patients diagnosed between 01 April 2020 and 31 March 2021, and patients diagnosed between 01 April 2019 and 31 March 2020 who underwent a major resection after 31 March 2020. All of these patients were diagnosed and/or treated during the COVID-19 pandemic and their outcomes were not outlier-reported. The only outcome that was outlier-reported in the 2022 report was 2-year all-cause mortality after major resection because it included patients having surgery before the pandemic.

The 2023 report included patients diagnosed between 01 April 2021 and 31 March 2022. All of these patients were diagnosed and/or treated during the COVID-19 pandemic and their outcomes were not outlier-reported. The only outcome that was outlier-reported in the 2023 report was 2-year all-cause mortality after major resection because it included patients having surgery before the pandemic.

Which patients are included in the outlier-reported measures in the 2023 annual report?

The only outcome that is outlier-reported in the 2023 report is 2-year all-cause mortality rate after major resection because it includes patients having surgery before the pandemic.

Which patients are included in the estimate of 2-year mortality rate in the 2023 report?

All patients aged 18 or over who, according to NBOCA, underwent a major resection between 01 April 2019 and 31 March 2020 (regardless of surgical urgency or curative intent).

Patients with cancer of the appendix, and patients missing date of surgery or whose date of surgery is reported to be after their date of death are excluded. Patients for whom ONS date of death is unavailable are excluded.

Which patients are included in trust risk-adjusted length of stay in the 2023 report?

All patients aged 18 or over diagnosed between 1 April 2021 and 31 March 2022 who (according to NBOCA) underwent an elective/scheduled major resection. Patients with cancer of the appendix and patients who could not be linked to HES/PEDW were excluded.