Association Between Purchase of Over-the-Counter Medications and Ovarian Cancer Diagnosis in the Cancer Loyalty Card Study (CLOCS): Observational Case-Control Study

Abstract

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

Using online search activity for earlier detection of gynaecological malignancy

“…As noted earlier, there are numerous examples, including mobile telephone data, social media posts, credit card use, loyalty card use and wearable device data. The recent CLOCS study 34 , evaluated loyalty card purchases within two retailers in 153 women with OC, compared to healthy controls, to determine if shopping habits could be used as proxy symptoms indicators and facilitate the detection of disease. Whilst an association between OC and purchases of over-the-counter indigestion (AUC 0.65) and pain (AUC 0.63) medications was identified, the results must be interpreted with an element of caution, given the control group consisted of healthy population rather than symptomatic women with a benign condition.…”

Cancer Loyalty Card Study (CLOCS): feasibility outcomes for an observational case–control study focusing on the patient interval in ovarian cancer

“…The aims, design and results of CLOCS have previously been reported 9 10. CLOCS is an observational case–control study where participants are women in the UK, aged 18 years or older, who hold a loyalty card at either or both participating high street retailers (HSR1 and HSR2).…”

“…The Cancer Loyalty Card Study (CLOCS) investigated the period between the presentation of the first symptom(s)/sign(s) leading up to the first presentation at healthcare providers (ie, the patient interval) of patients with ovarian cancer to better understand self-care behaviours using past purchase information collected through loyalty cards at two high street retailers in the UK 9. This project aimed to better understand whether self-care behaviours can be detected at an early stage and facilitate earlier presentation to healthcare providers, and the main results have been reported elsewhere 10. We have previously reported in a proof-of-concept study that loyalty card data may be used to identify an increase in painkiller and indigestion medication purchases among patients with ovarian cancer 11.…”

“… 9 This project aimed to better understand whether self-care behaviours can be detected at an early stage and facilitate earlier presentation to healthcare providers, and the main results have been reported elsewhere. 10 We have previously reported in a proof-of-concept study that loyalty card data may be used to identify an increase in painkiller and indigestion medication purchases among patients with ovarian cancer. 11 The proof-of-concept study warranted testing this hypothesis in a large-scale case–control study design aiming to include 500 patients with ovarian cancer (cases) and 500 individuals without an ovarian cancer diagnosis (controls).…”

Ovarian cancer: Loyalty card data could help identify cases sooner

“…Data from loyalty cards used in over-the-counter purchases of medicines could be used to help diagnose ovarian cancer cases earlier, a study published in JMIR Public Health and Surveillance has suggested 1…”