Internet-Based Follow-Up Questionnaire for Measuring Patient-Reported Outcome after Total Hip Replacement Surgery—Reliability and Response Rate

ObjectiveThis randomized methodologic study sought to test the reliability of an Internet questionnaire and investigate the differences in response rates between traditional pen-and-paper questionnaires and Internet questionnaires for measuring patient-reported outcome after total hip replacement surgery.MethodsFrom the Swedish Hip Arthroplasty Register, 2400 patients were chosen at random but stratified by age, sex, and diagnosis for inclusion in a 4-year follow-up using the health-related quality of life tool EQ-5D and visual analogue scales for pain and satisfaction. The patients were randomized to answer the follow-up model protocol either via a password-protected Internet questionnaire or via a mailed pen-and-paper questionnaire.ResultsA reliability test for the Internet follow-up instrument showed adequate correlation. However, the Internet group and the pen-and-paper group differed significantly (P < 0.001) with a 92% response rate in the latter and 49% in the former. Adjusted to the normal age distribution of the total hip replacement population, the Internet response rate was 34%.ConclusionsThe patient-administered Internet questionnaire alone does not give a sufficient response rate in the total hip replacement population to replace the pen-and-paper questionnaire. However, the system is reliable and could be used for measuring patient-reported outcome if supplemented with traditional pen-and-paper questionnaires for Internet nonrespondents. It is expected that this answer procedure will soon predominate in view of the general development of Internet functions. Register work may then become less resource-consuming and the results may be analyzed in real time.