ARIC is a population-based cohort study of 15,792 individuals recruited in 1987–89 from 4 US communities (Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; Minneapolis, Minnesota; Figure 2 ). The institutional review board of the participating institutions (Johns Hopkins University, University of Mississippi, Wake Forest University, University of Minnesota, Baylor University, University of Texas, and University of North Carolina) approved the ARIC study protocol and study participants provided written informed consent. This study consisted of 1 baseline visit (visit 1) and 3 followup visits (visits 2, 3, and 4) administered 3 years apart. Importantly, there was a surveillance component to ARIC throughout the followup period. When a participant was hospitalized within the catchment area of the participating institutions, all of the corresponding discharge diagnoses were recorded.
Our study population consisted of men and women who self-reported their gout status at visit 4. Notably, at ARIC visit 4 each participant was asked, “Has a doctor ever told you that you had gout?”. Participants who answered “Yes” were considered to have a self-reported, physician-diagnosed case of gout. If a participant was recorded through surveillance as having a hospital discharge summary that listed an International Classification of Diseases (ICD)-9 code for gout (274.0, 274.1, 274.8, or 274.9), then they were considered to have gout based on this assignment of a gout discharge diagnosis. Therefore, if a participant attended visit 4 and the date of the gout-related hospitalization was prior to the visit 4 date, they were considered to be a gout case for the assessment of sensitivity. In addition, at each of the 4 ARIC visits, all medications used within the preceding month were recorded. We defined gout medications as colchicine, probenecid, and allopurinol. If a participant reported the use of any of these 3 medications at any study visit, they were considered to be a gout case. In our study, the gold standard for a diagnosis of gout was defined as either a hospital discharge diagnosis of gout or use of gout medication at any cohort visit. Although a prescription for these medications does not mean with absolute certainty that the ARIC participant has gout, in a random sample of 4 US communities, a prescription for colchicine, allopurinol, or probenecid is most likely issued to treat gout.
The gold standard gout definition was applied to all participants who attended visit 4. We calculated the sensitivity of a self-report of physician-diagnosed gout. Sensitivity was defined as the percentage of gold standard gout cases with a corresponding affirmative self-report of gout on the visit 4 questionnaire. Next, we conducted a stratified analysis for the sensitivity of a self-report of physician-diagnosed gout by sex, race, education, and hyperuricemia (serum urate level > 7.0 mg/dl at either visit 1 or 2) categories.
Additionally, we performed a sensitivity analysis to assess whether the sensitivity of a report of gout at visit 4 depended upon the definition of the gold standard. Specifically, we calculated sensitivity, separately, for participants with a hospital discharge diagnosis of gout as well as for those using gout medications. All analyses were performed in SAS, version 9.1 (SAS Institute, Cary, NC, USA).
Our study population consisted of men and women who self-reported their gout status at visit 4. Notably, at ARIC visit 4 each participant was asked, “Has a doctor ever told you that you had gout?”. Participants who answered “Yes” were considered to have a self-reported, physician-diagnosed case of gout. If a participant was recorded through surveillance as having a hospital discharge summary that listed an International Classification of Diseases (ICD)-9 code for gout (274.0, 274.1, 274.8, or 274.9), then they were considered to have gout based on this assignment of a gout discharge diagnosis. Therefore, if a participant attended visit 4 and the date of the gout-related hospitalization was prior to the visit 4 date, they were considered to be a gout case for the assessment of sensitivity. In addition, at each of the 4 ARIC visits, all medications used within the preceding month were recorded. We defined gout medications as colchicine, probenecid, and allopurinol. If a participant reported the use of any of these 3 medications at any study visit, they were considered to be a gout case. In our study, the gold standard for a diagnosis of gout was defined as either a hospital discharge diagnosis of gout or use of gout medication at any cohort visit. Although a prescription for these medications does not mean with absolute certainty that the ARIC participant has gout, in a random sample of 4 US communities, a prescription for colchicine, allopurinol, or probenecid is most likely issued to treat gout.
The gold standard gout definition was applied to all participants who attended visit 4. We calculated the sensitivity of a self-report of physician-diagnosed gout. Sensitivity was defined as the percentage of gold standard gout cases with a corresponding affirmative self-report of gout on the visit 4 questionnaire. Next, we conducted a stratified analysis for the sensitivity of a self-report of physician-diagnosed gout by sex, race, education, and hyperuricemia (serum urate level > 7.0 mg/dl at either visit 1 or 2) categories.
Additionally, we performed a sensitivity analysis to assess whether the sensitivity of a report of gout at visit 4 depended upon the definition of the gold standard. Specifically, we calculated sensitivity, separately, for participants with a hospital discharge diagnosis of gout as well as for those using gout medications. All analyses were performed in SAS, version 9.1 (SAS Institute, Cary, NC, USA).
