Breast cancer – standardised 28-day readmission ratio following surgery
Metric
The ratio of the observed number of readmissions to the expected number of readmissions, multiplied by 100.
Numerator
All spells with an emergency readmission within 28 days of discharge.
Denominator
Expected number of readmissions within 28 days for patients having a breast excision procedure with breast cancer as a primary diagnosis. Any inpatient with a primary procedure of one of the following OPCS codes:
- B27 Total excision of breast
- B28 Other excision of breast
Equivalent to combining “Excision of breast” and “Excision of breast lump” procedure groups in the DFI tools
And a primary diagnosis of one of the following ICD10 codes:
- C50 Malignant neoplasm of breast
Data Source
SUS – CDS
Time frame
April 2010 – March 2011
Basis
Acute trust
Statistical methods used
Expected counts are derived from logistic regression, adjusting for:
- Sex
- Age on admission (in five year bands up to 90+)
- Admission method (non-elective or elective)
- Socio-economic deprivation quintile of the area of residence of the patient (based on the Carstairs Index)
- Procedure subgroup
- Co-morbidities (Dr Foster methodology)
- Number of previous emergency admissions in last 12 months
- Year of discharge (financial year)
- Palliative care (if any episode in the spell has the treatment function code 315 or contains ICD10 code Z515 in any of the diagnoses fields)
- Month of admission
- Source of admission
Logistic regression
The ratio is calculated by dividing the actual number of readmissions by the expected number and multiplying the figure by 100. It is expressed as a relative risk, where a risk rating of 100 represents the national average. If the trust has a SRR of 100, that means that the number of patients who were readmitted is exactly as would be expected taking into account the standardisation factors. A SRR above 100 means more patients were readmitted than would be expected; one below 100 means that fewer than expected were readmitted.
Control limits
Control limits tell us the range of values which are consistent with random or chance variation. Data points falling within the control limits are consistent with random or chance variation and are said to display ‘common-cause variation’; for data points falling outside the control limits, chance is an unlikely explanation and hence they are said to display ‘special-cause variation’ – that is, where the trust’s rate diverges significantly from the national rate.
Data points falling above the upper 99.8% control limit are said to be significantly ‘higher than expected’, data points falling below the lower 99.8% control limit are said to be significantly ‘lower than expected’, otherwise ‘within expected range’.
Notes
ICD10 contains no TNM staging information therefore we have tried to reproduce the essence using primary and secondary diagnosis fields. ‘Local spread’ requires the presence of a code for a local lymph node AND the absence of codes for distant nodes or organs. ‘Distant spread’ requires the presence of a code for distant nodes or organs (there may also be codes for local node or organ involvement present).
The denominator procedure groups “Excision of breast” and “Excision of breast lump” will both be organised to contain the following procedure subgroups within the DFI tools and for the purposes of risk adjustment. This indicator is a collation of the first 3 subgroups.
| Subgroup title | Primary diagnosis codes | Secondary diagnosis codes |
|---|---|---|
| 1. Breast only, no nodes | C50 | No other C |
| 2. Breast only, local nodes | C50 | C773 (axillary and upper limb lymph nodes) and no other C77-C79 |
| 3. Breast only, distant spread | C50 | C77-C79 excl C773 |
| 4. All other diseases | Not C50 | Any |
Comment from the Dr Foster Hospital Guide Team
We suggest further refining the table above to provide greater definition. The new codes would be:
| Subgroup title | Primary diagnosis codes | Secondary diagnosis codes |
|---|---|---|
| 1. Breast, no nodes | C50 | Any excl C77-C79 |
| 2. Breast, local spread | C50 | C773 (axillary and upper limb lymph nodes) if no other C77-C79 |
| 3. Breast, distant spread | C50 | Any C excl C773 |
| 4. All other diseases (includes ca in situ in breast) | Any except C50 | Any |
This is an example of an indicator which is similar, but not quite the same, as the IC Clinical Indicators used for NHS Choices. They report 3 for readmissions in breast cancer care:
I00330: Standardised ratio of emergency readmissions to hospital within 28 days of being discharged following conservative surgery for breast cancer
I00652: Standardised ratio of emergency readmissions to hospital within 28 days of being discharged following mastectomy for breast cancer with reconstruction
I00653: Standardised ratio of emergency readmissions to hospital within 28 days of being discharged following mastectomy for breast cancer without reconstruction
All the codes, method of standardisation etc are available and are of course different to yours
The difficulty from the Trust point of view is that the number of indicators with small variations from Dr Foster, Choices and CQC (in the QRPs) means we have an unmanageably large and complex set of indicators to keep track of (the Medical Director of each trust signs off the data from the IC for Choices each month).
Ideally we would consolidate the indicators to an agreed set. This would aid both accountability and more importantly improvement work as we are distracted by checking data against indicators and trying to explain all these technical differences to consultants, senior managers and Boards.
Although I’m commenting here on breast cancer, clearly the issue applies to other indicators you’re consulting on for the Hospital Guide this year.
Most readmissions following breast cancer surgery are planned readmissions following final histology of surgical specimens. This may be for positive sentinel lymph node biopsy requiring subsequent axillary node clearance (most hospitals do no perform intra-operative assessment of SLNs), or for wider re-excision / mastectomy due to previously unsuspected extent of in situ carcinoma. Is it intended to separate these elective readmissions from the rarer unplanned re-admissions for complications?
Not a good marker of success. A surgeon may remove large chunks of breast tissue leaving a poor cosmetic result, but will have a low readmision rate. Conversly a surgeon trying to remove disease but also preserve shape may need to re excise close margins but ultimately will have a better patient outcome.
I echo the above comments. This is not a valuable tool and is too blunt to be any sort of marker of quality. It may simply be a re-admission for planned radiotherapy. It should not be used by this group (Dr Foster) or be publicised as a factual representation
I agree with the comments above. This is too blunt aa assessment to be useful. Look for more specific issues to highlight surgical care quality…such infection or haematoma rates.
The above comments are all correct. An indicator should only look at emergency re-admission or it is of no value, or actually a potential for harm.
The problem with such an indicator is that it could encourgae bad practice, rather than benefiting patients. It shows a lack of understanding of modern breast surgery that tries to achieve a clear margin with a good cosmetic result. Inevitably that will increase the need for re-excision. Some of these compromises are after full discussion and patient choice which is entirely appropriate.