A comparison of three questionnaire-based measures of analgesic use over 11 years in adult males: A retrospective analysis of data from a prospective, population-based cohort study

Background: Few data are available on whether 3 commonly used, yet slightly different, questionnaire-based measures assessing the use of analgesics provide congruent and comparable results. Objective: The objective of this study was to compare 3 different measures of analgesic use in 1 study population over an 11-year period. Methods: Data for this study were gathered from a prospective, population-based cohort study in which 3 different measures were applied simultaneously for measuring use of analgesics at baseline, 4 years, and 11 years. The first measure was "weekly analgesic use in general," the second measure "analgesic use for pain symptoms within the past week," and the third measure "giving the name of any analgesic used within the past week." The subjects were Finnish men who completed 11 years of follow-up in the Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, conducted at the Research Institute of Public Health, University of Kuopio, Kuopio, Finland. Agreement between the 3 different measures was determined by Kappa statistics. Results: A total of 829 men completed 11 years of follow-up (mean [SD] age, 51.4 [6.7] years at baseline; 62.4 [6.5] at study end). At baseline, the prevalence of weekly analgesic use varied from 12.3% to 17.4% and at 11 years from 16.5% to 25.9%, depending on which measure was being used. The third measure yielded the highest prevalence at all 3 points of time and the lowest was obtained using the first measure. The Kappa agreement between the 3 measures at the 3 time points varied from moderate (0.37) to good (0.71). Conclusions: The results of this study suggest that the measure being used influences the obtained prevalence of analgesic use. All 3 measures tested consistently throughout the course of the study. The best results, with regard to determining prevalence, were obtained by asking the respondents to name the medicines they had been using during the previous week.