Year 2 Changes to the HES Number Estimates

The number of expected laparotomies taking place at each participating hospital will change for Year 2 of the Patient Audit beginning in December 2015.

Reasons for an increase in the estimated number of emergency laparotomies across NHS trusts

The original estimates were obtained from six years of HES data (01 April 2006 - 31 March 2012) consisting of patients who had undergone one of a selected set of procedures during an emergency admission to hospital. The revised estimates were based on a new HES extract that contained records for patients who had one of these procedures during an elective as well as emergency admission.

  • Therefore, the original estimate underestimated the numbers of patients undergoing an EL as a second operation after a valid elective OPCS code

Eligibility of return to theatre procedures

The original estimates did not include emergency laparotomy (EL) procedures that occurred after an ineligible operative procedure code. This group is made up of:

  • Those whose first procedure was ineligible for inclusion due to procedure type (OPCS code)
  • Those whose first procedure (valid OPCS code) was ineligible for inclusion as it occurred during an elective admission (presumed to be an elective procedure)
  • Those whose first procedure (valid OPCS code) was ineligible for inclusion due to the associated presumed diagnosis (first ICD-10 code listed in HES)

Number of included ICD-10 diagnosis codes changed

  • All diagnoses were included in the final estimate because we believe our methodology is better at discriminating whether the first procedure occurred during a HES episode with an eligible NELA diagnosis

Limitations of work:

We have tried to account for changes in patterns of care within/ between Trusts, but our estimates may not fully capture recent reorganisations of emergency surgical care.

Due to the nature of HES data, the following assumptions have been made:

  • Elective/emergency admissions were coded appropriately
  • Multiple procedures listed on the same date occur during the same operation (visit to theatre)
  • The initial procedure during an emergency admission was performed as an emergency procedure
  • Subsequent procedures during an admission (either elective/emergency) are emergency procedures and not planned follow-up procedures
  • The first ICD-10 code (diag01) in the episode of care during which the first operation occurs is an accurate description of the patients diagnosis.