This study aimed to develop an efficient data collection and curation process for all drugs and natural health products (NHPs) used by participants to the Canadian Longitudinal Study on Aging (CLSA). The three-step sequential process consisted of (a) mapping drug inputs collected through the CLSA to the Health Canada Drug Product Database (DPD), (b) algorithm recoding of unmapped drug and NHP inputs, and (c) manual recoding of unmapped drug and NHP inputs. Among the 30,097 CLSA comprehensive cohort participants, 26,000 (86.4%) were using a drug or an NHP with a mean of 5.3 (SD 3.8) inputs per participant user for a total of 137,366 inputs. Of those inputs, 70,177 (51.1%) were mapped to the Health Canada DPD, 20,729 (15.1%) were recoded by algorithms, and 44,108 (32.1%) were manually recoded. The Direct algorithm correctly classified 99.4 per cent of drug inputs and 99.5 per cent of NHP inputs. We developed an efficient three-step process for drug and NHP data collection and curation for use in a longitudinal cohort.
