How to evaluate and improve the quality and credibility of an outcomes database: validation and feedback study on the UK Cardiac Surgery Experience

Abstract

Objectives: To assess the quality and completeness of a database of clinical outcomes after cardiac surgery and to determine whether a process of validation, monitoring, and feedback could improve the quality of the database.

Design: Stratified sampling of retrospective data followed by prospective re-sampling of database after intervention of monitoring, validation, and feedback.

Setting: Ten tertiary care cardiac surgery centres in the United Kingdom.

Intervention: Validation of data derived from a stratified sample of case notes (recording of deaths cross checked with mortuary records), monitoring of completeness and accuracy of data entry, feedback to local data managers and lead surgeons.

Main outcome measures: Average percentage missing data, average kappa coefficient, and reliability score by centre for 17 variables required for assignment of risk scores. Actual minus risk adjusted mortality in each centre.

Results: The database was incomplete, with a mean (SE) of 24.96% (0.09%) of essential data elements missing, whereas only 1.18% (0.06%) were missing in the patient records (P<0.0001). Intervention was associated with (a) significantly less missing data (9.33% (0.08%) P<0.0001); (b) marginal improvement in reliability of data and mean (SE) overall centre reliability score (0.53 (0.15) v 0.44 (0.17)); and (c) improved accuracy of assigned Parsonnet risk scores (kappa 0.84 v 0.70). Mortality scores (actual minus risk adjusted mortality) for all participating centres fell within two standard deviations of the mean score.

Conclusion: A short period of independent validation, monitoring, and feedback improved the quality of an outcomes database and improved the process of risk adjustment, but with substantial room for further improvement. Wider application of this approach should increase the credibility of similar databases before their public release.

Figure 1

Average EuroSCOREs and Parsonnet scores for retrospective review of mortality data for coronary artery bypass surgery, comparing scores submitted by surgical centres, the same submitted data recalculated by RAND statisticians, and the scores calculated on re-abstracted data. Parsonnet scores submitted by centres were significantly higher than recalculated scores or scores derived from re-abstracted data (*P<0.05)

Figure 2

Actual mortality minus risk adjusted (expected) mortality by surgical centre in retrospective review. Risk adjustment was made with either Parsonnet scores or EuroSCOREs. Participating centres were 1 Queen Elizabeth Medical Centre, Birmingham; 2 Bristol Royal Infirmary; 3 Papworth Hospital NHS Trust; 4 Victoria Hospital, Blackpool; 5 Wythenshawe Hospital, Manchester; 6 Freeman Hospital, Newcastle; 7 Guy's and St Thomas's Hospitals, London; 8 Kings College Hospital, London; 9 Imperial College School of Medicine, Hammersmith Hospital, London; 10 University College London Hospitals, London