Clinical Trial: Cumulative antibiotic exposure over five years and the incidence of colorectal cancer: a risk-set-matched nested case-control study in a Japanese health insurance claims database (Japan)

Tokyo, Sept. 23 -- UMIN Clinical Trials Registry (UMIN-CTR) received information related to the study (UMIN000063019) titled 'A study of the association between cumulative antibiotic exposure over five years and the subsequent incidence of colorectal cancer, using a Japanese health insurance claims database (risk-set-matched nested case-control study)' on Sept. 22.

Study Type: Observational

Primary Sponsor: Institute - The University of Osaka, Graduate School of Medicine Faculty of Medicine

Condition: Condition - Colorectal cancer (colon and rectal cancer, ICD-10 C18-C20, excluding appendix). The exposure is cumulative systemic antibiotic use. Classification by malignancy - Malignancy Genomic information - NO

Objective: Narrative objectives1 - Using the JMDC claims database (2005-2025, restricted to enrollees with a prior systemic anti-infective prescription), to estimate the association between cumulative days of systemic antibiotic coverage during the five years (60 months) ending 24 months before diagnosis and incident colorectal cancer, using a risk-set-matched nested case-control design. Up to five controls per case are matched on sex, birth month, enrollment start month, and age group (under 50 vs 50 or older), and odds ratios adjusted for healthcare use, infections, comorbidities, and co-medications are estimated by conditional logistic regression with person-level cluster-robust variance. Adults under 50 years are also evaluated separately. Basic objectives2 - Others

Eligibility: Age-lower limit - Not applicable Age-upper limit - Not applicable Gender - Male and Female Key inclusion criteria - The source population is JMDC claims database enrollees (2005-2025) with a history of systemic anti-infective (EphMRA ATC group J) prescribing. (1) Cases: a first confirmed (non-suspected) colorectal cancer diagnosis (ICD-10 C18-C20, excluding appendix and others). (2) Controls: for each case, enrollees at risk in the diagnosis month, matched on sex, birth month (plus or minus 12 months), enrollment start month (plus or minus 12 months), and age group (under 50 vs 50 or older) at the diagnosis month; up to five controls per case are selected by a reproducible random ordering (controls may be reused and may later become cases). (3) Eligibility: enrollment begins at least 12 months before the exposure window, and the first anti-infective prescription precedes the window start. The exposure window is the 60 months ending 24 months before diagnosis. All ages. Key exclusion criteria - An explicit recurrence code at or before the first colorectal cancer diagnosis, or a code for colorectal-cancer-derived bone metastasis preceding it (excluded as prevalent). Cases with indeterminate exposure due to missing prescription dates or days (the set is dropped), and indeterminate controls (removed individually). Records with only a suspected flag. Target Size - 32227

Recruitment Status: Recruitment status - Completed Date of protocol fixation - 2026 Year 04 Month 14 Day Date of IRB - 2026 Year 04 Month 14 Day Anticipated trial start date - 2026 Year 04 Month 14 Day Last follow-up date - 2026 Year 09 Month 22 Day

To know more, visit https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000072142

Disclaimer: Curated by HT Syndication.