The new network study is launched to compare the risk of incident cancer between histamine-2 receptor antagonists.
Comparative risk of the incident cancer between histamine-2 receptor antagonists
Abstract: Dietary N-nitrosodimethylamine (NDMA) has been shown to be carcinogenic in animals, however, evidence from population-based studies is inconlusive. The U.S. Food and Drug Administration has issued a statement on ranitidine because they may contain unacceptable levels of NDMA in 2019.
To date, there have been several studies regarding association between NDMA exposure and risk of cancer, however, real-world evidence of cancer risk in relation with ranitidine is scarce. We aim to evaluate the comparative risk of incident cancer in patients exposed to various H2 receptor antagonists (H2RAs).
We will conduct systematic, multinational study to estimate the relative risk of primary outcome (overall cancer except thyroid cancer) and secondary outcomes (overall cancer, 16 types of cancer, and cancer mortality) in ranitidine cohort. We will compare the target cohort with the comparator cohort for the hazards of outcome during the time-at-risk by applying a Cox proportional hazards model after propensity score adjustment.
Currently, We are searching for collaborators to join this network study and to execute feasibility test of this study. Please follow the instruction, and please send me the result from the feasibility test first before running execute function).
The current results from feasibility test will be presented at March 3rd OHDSI call.
If you have any question, comments, or suggestion, please let me know.
Whatās the difference between āoverall cancerā and āoverall cancerā? And whatās the difference between a primary and secondary outcome in observational studies anyway, @SCYou? We cannot distinguish between more direct or indirect consequences, can we?
Sorry for confusion, @Christian_Reich
We excluded thyroid cancer from the primary outcome (āoverall cancer except thyroid cancerā), due to epidemic of thyroid cancer in South Korea (ref1, ref2)
Although we will empirical calibration and publish all the results to minimize publication bias, and the bias caused by systematic or unmeasured sources, I set the primary outcome and analysis to avoid cherry-picking and question trolling in writing a paper based on substantial amount of evidences.
Not sure why excluding the overdiagnosed patients in thyroid cancer. There are many cancers that have screening problems, the most notable are breast and prostate. Thyroid cancer could still be caused by ranitidine, and since you do a comparison the overdiagnosing would equally happen in both the test and the comparator cohorts.
How would the cherry picking argument go away just because you run both overall cancer and specific cancers? Letās say the overall is not significant, but some of the specific cancers are. Now what? Want to exclude them? Or the other way around, overall there is a signal but the CE of certain cancers does include 1. As long as it is all reported you are good.
I would just list all the outcomes. Primary and secondary is a concept from clinical trials to deal with sample size problems.
It makes sense. Another reason would be exceptionally favorable prognosis of thyroid cancer. And incidence of thyroid cancer itself is another outcome in this study.
Again, it makes sense.
First of all, Iād like to measure available sample size in cohort and incidence of outcomes through feasibility test phase of this study. Our protocol can be changed after feasibility test (I shouldāve mentioned that). If our sample size is big enough and the result for our primary endpoint was negative, then the final conclusion can be āThere is no significant difference in incidence of cancer except thyroid cancer between ranitidine use and cimetidine use. But we found increased risk of several cancer types including thyroid, ā¦ā after network study.
