%0 Journal Article
%@ 2369-2960
%I JMIR Publications
%V 9
%N 
%P e41762
%T Association Between Purchase of Over-the-Counter Medications and Ovarian Cancer Diagnosis in the Cancer Loyalty Card Study (CLOCS): Observational Case-Control Study
%A Brewer,Hannah R
%A Hirst,Yasemin
%A Chadeau-Hyam,Marc
%A Johnson,Eric
%A Sundar,Sudha
%A Flanagan,James M
%+ Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, 4th Floor IRDB, Hammersmith Campus, Du Cane Rd, London, W12 0NN, United Kingdom, 44 2075942127, j.flanagan@imperial.ac.uk
%K ovarian cancer
%K early diagnosis
%K transactional data
%K health informatics
%K cancer risk
%K medication
%K self-medication
%K self-care
%K over-the-counter medication
%K nonspecific symptoms
%K pain medication
%K indigestion medication
%D 2023
%7 26.1.2023
%9 Original Paper
%J JMIR Public Health Surveill
%G English
%X Background: Over-the-counter (OTC) medications are frequently used to self-care for nonspecific ovarian cancer symptoms prior to diagnosis. Monitoring such purchases may provide an opportunity for earlier diagnosis. Objective: The aim of the Cancer Loyalty Card Study (CLOCS) was to investigate purchases of OTC pain and indigestion medications prior to ovarian cancer diagnosis in women with and without ovarian cancer in the United Kingdom using loyalty card data. Methods: An observational case-control study was performed comparing purchases of OTC pain and indigestion medications prior to diagnosis in women with (n=153) and without (n=120) ovarian cancer using loyalty card data from two UK-based high street retailers. Monthly purchases of pain and indigestion medications for cases and controls were compared using the Fisher exact test, conditional logistic regression, and receiver operating characteristic (ROC) curve analysis. Results: Pain and indigestion medication purchases were increased among cases 8 months before diagnosis, with maximum discrimination between cases and controls 8 months before diagnosis (Fisher exact odds ratio [OR] 2.9, 95% CI 2.1-4.1).  An increase in indigestion medication purchases was detected up to 9 months before diagnosis (adjusted conditional logistic regression OR 1.38, 95% CI 1.04-1.83). The ROC analysis for indigestion medication purchases showed a maximum area under the curve (AUC) at 13 months before diagnosis (AUC=0.65, 95% CI 0.57-0.73), which further improved when stratified to late-stage ovarian cancer (AUC=0.68, 95% CI 0.59-0.78). Conclusions: There is a difference in purchases of pain and indigestion medications among women with and without ovarian cancer up to 8 months before diagnosis. Facilitating earlier presentation among those who self-care for symptoms using this novel data source could improve ovarian cancer patients’ options for treatment and improve survival. Trial Registration: ClinicalTrials.gov NCT03994653; https://clinicaltrials.gov/ct2/show/NCT03994653 
%M 36701184
%R 10.2196/41762
%U https://publichealth.jmir.org/2023/1/e41762
%U https://doi.org/10.2196/41762
%U http://www.ncbi.nlm.nih.gov/pubmed/36701184