Introduction: Collecting clinical data is viewed as the gold standard for assessing health-care quality. However, considerable investment is needed if the quality of care is to be recorded over a long period of time. Accordingly, the question arises as to whether routine administrative data may be used for quality assurance purposes if certain methodological standards are followed. This present study now compares the outcomes of inguinal hernia repair from the Herniamed Hernia Registry with routine data from Germany's largest sickness fund, the Local General Sickness Fund "AOK".
Materials and methods: Included in the study were the hospital inpatient cases for the years 2011-2013 with inguinal hernia surgical repair whose data had been prospectively entered into the voluntary Herniamed Hernia Registry by 318 participating hospitals. These collectives were then compared, on the basis of the routine administrative data available, with patients from the AOK sickness fund who had been operated on during the same time period. The outcome criteria selected were the perioperative complication rates within 30 days as well as the recurrence rate and the pain rate requiring treatment at 1-year follow-up.
Results: The data records examined comprised 64,748 cases from the Herniamed Registry and 130,121 AOK cases. Since in the Herniamed collective, the proportion of bilateral procedures was significantly higher, only the collectives of elective primary unilateral inguinal hernias in men (Herniamed n = 37,667; AOK n = 78,973) were compared. The most pronounced difference between these two collectives was in the proportion of laparo-endoscopic procedures (Herniamed 61.3% vs AOK 49.0%; p < 0.001). Accordingly, the Herniamed collective was found to have a significantly lower postoperative surgical complication rate (Herniamed 1.5% vs AOK 2.6%; p < 0.001) and surgical site infection (SSI) rate (Herniamed 0.3% vs AOK 0.6%; p < 0.001) within 30 days after the operation. On the other hand, the pain rates requiring treatment in the Herniamed collective were somewhat higher (Herniamed 3.0% vs AOK 2.6%; p < 0.001). No difference was found in the recurrence rate at 1-year follow-up (Herniamed 1.0% vs AOK 0.9%; ns).
Conclusion: Subject to critical evaluation of the limitations of data acquisition in this study, it does appear possible to use the routine administrative data from the AOK Sickness Fund for assessment of the quality of inguinal hernia surgery in Germany. Voluntary participation in the Herniamed Registry appears to be characterized by the fact that the participating hospitals conduct a higher proportion of laparo-endoscopic inguinal hernia repair. That could possibly explain the differences in outcome. However, in large patient collectives, statistical significance should not always be equated with clinical relevance. Univariate analysis does not take account of differences in the hernia findings, risk factors or operative details. Further efforts should be employed in future to improve the accuracy and granularity of routine administrative data for assessing the quality of care and to decrease the cost of gathering such data.
Keywords: Hernia registry; Inguinal hernia; Outcome; Routine data; TAPP; TEP.