The UK nephrostomy audit. Can a voluntary registry produce robust performance data?

To investigate the effectiveness of the Royal College of Radiologists Audit Sub-Committee's national prospective registry of percutaneous nephrostomy, which enables participants to audit their practice and compare performance with predetermined standards.

Following a limited retrospective audit, which permitted setting of achievable targets, a dataset was developed and all UK NHS acute hospitals were invited to participate in web-based prospective data collection.

Eighty-five out of 285 (29.8%) hospitals contributed 3262 cases over a 29 month period. A satisfactory level of performance was achieved with an overall technical success rate of 98% and a complication rate of 6.3%. Significant risk factors for complications included rigors, anaemia, and impaired renal function. Low frequency operators were shown to have a lower technical success rate and a higher complication rate than high frequency operators; however, target thresholds were exceeded in all groups. Sepsis was identified as a risk factor in the majority of serious complications and all deaths. Some anomalous results were found due to unusual interpretation of the data entry form in two centres, but no evidence of under-performance was identified at any centre.

Some weaknesses of the registry are discussed. In view of the low response rate, the possibility of significant bias cannot be excluded. In addition, there is no objective verification of the data; therefore, the results have limited credibility. However, individual centres that accurately completed a representative sample of cases can have confidence that their performance achieves an acceptable standard.