Control participants were randomly selected and individually matched on age at screening, enrollment date, ethnicity (white, African American, Hispanic, other), hysterectomy status, and prevalent condition at baseline using risk set sampling.
Higher fetuin-A levels predicted incident diabetes regardless of sex, race, or prevalent CVD status (13).
Stratification will occur for study site, incident versus prevalent patient status and upper vs. lower arm site.
Individuals without stored blood (n = 109,625) or with prevalent diabetes status at baseline (n = 5,821) were not eligible for InterAct.
Baseline assessments of anthropometric data, medical history, therapeutic drug use, and prevalent fracture status were obtained from all participants.
In addition to these examinations, information on prevalent disease status is obtained by accessing data from the Nationwide Medical Registry (LMR, sourced by Dutch Hospital Data, Utrecht, The Netherlands).
In a fifth analysis, we stratified cases and matched controls on prevalent user status (this was a matching variable) to assess the effect of including prevalent users in the main models.
32 In addition to age, sex, calendar year of cohort entry, prevalent user status, and duration of follow-up on which the logistic regression was conditioned, we adjusted for the confounders described above.
Most importantly, clinical information on prevalent CVD status is obtained from the GPs for each participant: the entire medical records of the GPs are hand screened at the GPs' office by trained research assistants.
When we stratified the cases and matched controls by prevalent user status, the results were still consistent with those of the primary analysis; the triple therapy combination was associated with an increased risk of acute kidney injury in both prevalent and incident cases and controls.
If date of entry (age, time to blood draw) is used as a left truncation point, it does not need to be in the model as a covariate; in our example, prevalent case status would not need to be added to the left-truncated model (Klein and Moeschberger, 2003).
