Health care utilization: measurement using primary care records and patient recall both showed bias.

OBJECTIVE: To assess reasons for discrepancies between primary care consultation measured from patient self-report and that based on medical records.

METHODS: Retrospective comparison of recalled consultation in previous 12 months among 2,414 subjects aged 50+ who reported knee pain in a population survey vs. primary care medical records. Record review included (1) all knee morbidity codes and (2) knee problems mentioned in consultation text. It was then extended to: (3) more than 12 months before survey, and (4) consultations for leg or widespread problems (e.g., generalized osteoarthritis).

RESULTS: In those who reported knee pain, recalled consultation prevalence for knee problems "in past year" was 33% compared with 15% based on medical records. Forty percent of those with a recalled consultation had a recorded knee problem in the same time period (kappa = 0.43). Expanding record search to include leg and widespread problems, and knee problems up to 40 months prior to survey, increased "verified" self-reported consulters to 80%.

CONCLUSIONS: Disparity in estimates of consultation prevalence arose from inaccuracy of: (1) recall in survey responders and (2) recording by general practitioners of specific problems and repeat consultations. Perceived importance of problem in a multiproblem contact and whether it leads to an outcome (e.g., prescription) may influence recording. Implications exist for service provision projections and research.