Agreement between patient survey and medical chart: Pitfalls in measurement strategies for hernia recurrence

Background: Little information is available on agreement between patient-reported outcomes and data collected from medical chart abstraction (MCA) for recurring events. Recurring conditions pose a risk of misclassification, especially when events occur relatively close together in time. We examined agreement, predictors of agreement, and relative accuracy of patient survey and MCA for assessment of outcomes of incisional hernia repair (IHR). Methods: Surveys to assess hernia outcomes were mailed to 1,124 living patients who underwent ≥1 IHR during 1998-2002 at 16 Veteran's Affairs Medical Center study sites. Patients were asked if they developed a recurrence or an infection at their hernia site. Physician-abstracted data from the medical chart were compared with patient response. Chi-square tests were used to assess significance. Results: Of 487 (43.3%) individuals responding to the survey, 33 (6.8%) with >1 re-repair during 1998-2002 and 98 (20.5%) with a repair before the 1998-2002 period were excluded from the analysis. Although recurrence rates derived from self-reported data and data abstracted from the medical chart were similar (29.3% and 26.1%, respectively), overall concordance was low. Only 49% (n = 54) of self-reported recurrences were confirmed by data abstracted from the medical chart. In addition, 16 (8.3%) recurrences abstracted from the medical chart were not reported by the patient. Factors associated with discordance were high reported pain intensity (P =.02), poorer general health (P =.03), and poorer perceived repair results (P <.0001). Conclusion: Multiple recurrences and subsequent operations across the study period complicate the interpretation of both patient response and data abstracted from the medical chart when referring to a hernia repair. Further study on how best to assess treatment outcomes for recurring conditions is warranted.