ABSTRACT:
Objective:
To assess the agreement between three recall periods for self-reported drug use using a 24-hour recall period as reference.
Methods:
Participants were allocated into three groups with different recall periods of 7, 14 and 30 days and were interviewed at two different times. A 24-hour recall questionnaire was answered during the first interview, and a questionnaire on drug use over the different recall periods tested was answered during the second interview. The agreement between the questionnaires was evaluated using percent agreement and kappa.
Results:
For continuous drugs, percent agreement varied between 92 and 99% and kappa varied between 0.71 and 0.97 for three periods tested. For drugs of occasional use, percent agreement varied between 63 and 81% and kappa varied between 0.27 and 0.52. The prevalence of drugs, particularly those of occasional use, increases with time.
Conclusions:
The high level of agreement between the three recall periods suggests that all of them are valid for the investigation of drugs of continuous use.
Keywords:
Drug utilization; Questionnaires; Self report; Mental recall; Validation studies; Pharmacoepidemiology