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

Brewer, Hannah R; Hirst, Yasemin; Sundar, Sudha; Chadeau‐Hyam, Marc; Flanagan, James M.

doi:10.1136/bmjopen-2020-037459

Cited by 12 publications

(24 citation statements)

References 18 publications

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“…This study comprised a randomized web-based experiment, which assessed the effectiveness of adding an animated decision aid to a simulated website. The simulated website the animation was designed for (or added to) was the recruitment website for the case-control study: Cancer Loyalty Card Study (CLOCS) [ 17 ].…”

Section: Methodsmentioning

confidence: 99%

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Testing the Effectiveness of an Animated Decision Aid to Improve Recruitment of Control Participants in a Case-Control Study: Web-Based Experiment

Stoffel¹,

Law²,

Kerrison³

et al. 2022

J Med Internet Res

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Background Participation in case-control studies is crucial in epidemiological research. The self-sampling bias, low response rate, and poor recruitment of population representative controls are often reported as limitations of case-control studies with limited strategies to improve participation. With greater use of web-based methods in health research, there is a further need to understand the effectiveness of different tools to enhance informed decision-making and willingness to take part in research. Objective This study tests whether the inclusion of an animated decision aid in the recruitment page of a study website can increase participants’ intentions to volunteer as controls. Methods A total of 1425 women were included in a web-based experiment and randomized to one of two experimental conditions: one in which they were exposed to a simulated website that included the animation (animation; n=693, 48.6%), and one in which they were exposed to the simulated website without the animation (control; n=732, 51.4%). The simulated website was adapted from a real website for a case-control study, which invites people to consider taking part in a study that investigates differences in purchasing behaviors between women with and without ovarian cancer and share their loyalty card data collected through 2 high street retailers with the researchers. After exposure to the experimental manipulation, participants were asked to state (1) their intention to take part in the case-control study, (2) whether they would be willing to share their loyalty card for research, and (3) their willingness to be redirected to the real website after completing the survey. Data were assessed using ordinal and binary logistic regression, reported in percentages (%), adjusted odds ratio (AOR), and 95% confidence intervals. Results Including the animation in the simulated website did not increase intentions to participate in the study (AOR 1.09; 95% CI 0.88-1.35) or willingness to visit the real study website after the survey (control 50.5% vs animation 52.6%, AOR 1.08; 95% CI 0.85-1.37). The animation, however, increased the participants’ intentions to share the data from their loyalty cards for research in general (control 17.9% vs animation 26%; AOR 1.64; 95% CI 1.23-2.18). Conclusions While the results of this study indicate that the animated decision aid did not lead to greater intention to take part in our web-based case-control study, they show that they can be effective in increasing people’s willingness to share sensitive data for health research.

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Section: Methodsmentioning

confidence: 99%

“…Cases (ie, women with ovarian cancer) are recruited through participating National Health Service sites, while controls are recruited through the study website. Full details for CLOCS have previously been reported in the study protocol [ 17 ].…”

Section: Methodsmentioning

confidence: 99%

Testing the Effectiveness of an Animated Decision Aid to Improve Recruitment of Control Participants in a Case-Control Study: Web-Based Experiment

Stoffel¹,

Law²,

Kerrison³

et al. 2022

J Med Internet Res

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“…The CLOCS case-control study design and protocol have been described previously [9]. Eligible participants were women in the United Kingdom, 18 years or older, who owned at least one of the participating retailers' loyalty cards.…”

Section: Study Design Setting and Participantsmentioning

confidence: 99%

“…If the details did not match, then the purchase history was not shared, and the participant was recontacted up to two times to clarify their details. Once clarified, the participant's card history was requested once again as described previously [9].…”

Section: Study Design Setting and Participantsmentioning

confidence: 99%

“…A proof-of-concept study conducted in 2019 concluded that there may be an increase in purchases of pain and indigestion medications 10-12 months before ovarian cancer diagnosis to treat symptoms [8], although larger studies were needed to validate this finding. The Cancer Loyalty Card Study (CLOCS) was therefore proposed to investigate this further through an observational case-control study design, which hypothesized that a significant change in purchasing behavior, specifically an increase in self-medication prior to presentation in primary care, could be an indication for early signs of ovarian cancer [9]. The primary objective of the CLOCS is to investigate the purchasing behaviors of women with and without ovarian cancer using commercial data collected through loyalty card use at two participating high street retailers in the United Kingdom with the aim to reduce delays in ovarian cancer diagnosis.…”

Section: Introductionmentioning

confidence: 99%

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

Brewer¹,

Hirst²,

Chadeau‐Hyam³

et al. 2023

JMIR Public Health Surveill

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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

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Seasonal purchase of antihistamines and ovarian cancer risk in the Cancer Loyalty Card Study (CLOCS): results from an observational case-control study

Brewer

Jiang

Sundar

et al. 2023

Preprint

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Objective: Antihistamine use has previously been associated with a reduction in incidence of ovarian cancer, particularly in premenopausal women. Herein, we investigate antihistamine exposure in relation to ovarian cancer risk using a novel data resource by examining purchase histories from retailer loyalty card data. Study Design: A subset of participants from the Cancer Loyalty Card Study (CLOCS) for which purchase histories were available were analysed in this study. Cases (n=153) were women in the UK with a first diagnosis of ovarian cancer between Jan 2018 to Jan 2022. Controls (n=120) were women in the UK without a diagnosis of ovarian cancer. Up to 6 years of purchase history was retrieved from two participating high street retailers from 2014 to 2022. Main outcome measures: Logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals (CIs) for ovarian cancer associated with antihistamine purchases, ever versus never, adjusting for age and oral contraceptive use. The association was stratified by season of purchase, age over and under 50 years, ovarian cancer histology, and family history. Results: Ever purchasing antihistamines was not significantly associated with ovarian cancer overall in this small study (OR:0.68, 95% CI: 0.39,1.19). However, antihistamine purchases were significantly associated with reduced ovarian cancer risk when purchased only in spring and/or summer (OR: 0.37, 95% CI: 0.17,0.82) compared with purchasing all year (OR: 0.99, 95% CI: 0.51,1.92). In the stratified analysis, the association was strongest in non-serous ovarian cancer (OR: 0.41, 95% CI:0.18,0.93). Conclusions: Antihistamine purchase is associated with reduced ovarian cancer risk when purchased seasonally in spring and summer. However, larger studies and more research is required to understand the mechanisms of reduced ovarian cancer risk related to seasonal purchases of antihistamines and allergies.

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

Cited by 12 publications

References 18 publications

Testing the Effectiveness of an Animated Decision Aid to Improve Recruitment of Control Participants in a Case-Control Study: Web-Based Experiment

Testing the Effectiveness of an Animated Decision Aid to Improve Recruitment of Control Participants in a Case-Control Study: Web-Based Experiment

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

Seasonal purchase of antihistamines and ovarian cancer risk in the Cancer Loyalty Card Study (CLOCS): results from an observational case-control study

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