How accurate are Scottish Morbidity Record (SMR01) data for elective AAA procedures? Sarah Couper SpR in Public Health Medicine John Connor Principal Information Analyst, ISD Donna Nicholson Senior Information Analyst, ISD Jennifer Armstrong Senior Medical Officer, Scottish Government

Background Scottish screening programme for AAA due for phased roll-out 2011/2012 Some evidence exists which shows that the outcome of AAA surgery is dependent on the number of interventions per unit NHS QIS has produced clinical standards which refer to units undertaking a minimum of 20 elective interventions each year. (Level B) We wanted to answer the question of how many interventions were happening in Scottish units

SMR submission process

What we asked for –date of discharge between 1st April 2007 to 31st March 2010 – elective cases only, emergencies and transfers excluded – case attributed to main consultant – specific ICD10/OPCS4 code combinations (supplied by Julie Brittenden)

Diagnosis and procedure codes Diagnosis Code I71.4 Abdominal aortic aneurysm, without mention of rupture Procedure Codes Open Repair L19.4 Replacement of aneurysmal segment of infrarenal abdominal aorta by anastomosis of aorta to aorta NEC L19.5 Replacement of aneurysmal segment of abdominal aorta by anastomosis of aorta to aorta NEC L19.6 Replacement of aneurysmal bifurcation of aorta by anastomosis of aorta to iliac artery NEC L19.8 Other specified other replacement of aneurysmal segment of aorta. L19.9 Unspecified other replacement of aneurysmal segment of aorta. L21 Other bypass of segment of aorta EVAR L27.1 Endovascular insertion of stent graft for infrarenal abdominal aortic aneurysm. L27.5 Endovascular insertion of stent graft for aortic aneurysm of bifurcation. L28.1 Endovascular stenting for infrarenal abdominal aortic aneurysm. L28.8 Other specified transluminal operations on aneurysmal segment of aorta. L28.9 Unspecified transluminal operations on aneurysmal segment of aorta.

Outline of data collection process ISD generates case numbers based on agreed criteria Data reviewed by consultant for accuracy Consultant provides updated case numbers and requests patient details for verification ISD provides patient level case listings Consultant reviews data and verifies against local records Consultant sends additional case list with patient identifiers back to ISD ISD cross checks consultant responses against SMR01 and original criteria

Why did we ask for patient identifiers? Investigate the discrepancies in the data and correct the system for future use Avoid double counting of cases Clarify cases fit the case definition

44 Consultants contacted 15 No reply 29 (66%) Replied 9 (20%) Data reported as inaccurate by consultant but no amended data provided 2 no reason 3 too much time 4 in progress 12 (27%) Provided data No patient identifier 8 (18%) Provided patient identifiers

Method Number of interventions from SMR01 data + Number of additional cases reported by those consultants who responded = Total number of interventions

Level of discrepancy * only refers to those consultants who responded to exercise Discrepancy reported by responding consultants between SMR01 data and their records -43% 0% -20% -23% -20% -62% -10% -62% -17% - -32%

Analysis of the discrepancies for one Health Board 87% Different codes Emergency/transfer Out with date range Agreement with SMR01 data

Conclusions Selecting search criteria and ensuring these are adhered to is a complex exercise Cross-checking data with consultants was challenging due to workloads and data confidentiality/disclosure issues Data collection process could perhaps have been streamlined by asking consultants to provide patient level case details direct to ISD for verification Clinicians sometimes query the accuracy of nationally collected data Provisional analysis of the discrepancies show that many seem to be due to data extraction rather than inherent inaccuracy within the SMR01 records Further work cross-checking clinicians’ records to discuss the discrepancies with them would have been useful but out with the scope of this exercise