UMIN-ICDS Clinical Trial
| Unique ID issued by UMIN | UMIN000062534 |
|---|---|
| Receipt number | R000071588 |
| Scientific Title | Comparative effectiveness of doxycycline versus single-dose azithromycin for uncomplicated genital chlamydia infection: a target trial emulation using the JMDC insurer claims database |
| Date of disclosure of the study information | 2026/08/10 |
| Last modified on | 2026/08/10 11:11:48 |
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Basic information
Public title
A study comparing whether doxycycline (7 or more days orally) or single-dose azithromycin is less likely to require retreatment for uncomplicated genital chlamydia infection, using health insurance claims data (target trial emulation; the primary population is men)
Acronym
Chlamydia Treatment Comparison Study (JMDC)
Scientific Title
Comparative effectiveness of doxycycline versus single-dose azithromycin for uncomplicated genital chlamydia infection: a target trial emulation using the JMDC insurer claims database
Scientific Title:Acronym
Chlamydia Doxycycline vs Azithromycin TTE Study (JMDC)
Region
| Japan |
Condition
Condition
Uncomplicated genital Chlamydia trachomatis infection.
Classification by specialty
| Infectious disease | Obstetrics and Gynecology | Urology |
Classification by malignancy
Others
Genomic information
NO
Objectives
Narrative objectives1
Using the JMDC insurer claims database, to compare, for outpatient treatment of uncomplicated genital chlamydia infection, a strategy of starting oral doxycycline (initial supply of 7 or more days) at Day 0 versus a strategy of starting single-dose azithromycin, and to estimate the difference in 30-day retreatment risk within a target trial emulation framework. The primary estimand is the average treatment effect in the overlap population (ATO) by propensity-score overlap weighting; the primary population is men and women are a secondary population. This registration is performed before analysis and without reference to outcomes (after outcome-blinded feasibility).
Basic objectives2
Efficacy
Basic objectives -Others
Trial characteristics_1
Exploratory
Trial characteristics_2
Pragmatic
Developmental phase
Not applicable
Assessment
Primary outcomes
The primary outcome is a new anti-chlamydial treatment course started on days 15-30 (retreatment). Switching to a different agent requires no gap; re-dispensing of the same agent requires a no-medication gap of at least 7 days after the end of the initial supply (14 days as a sensitivity analysis). A diagnosis code is not required. The primary effect measure is the risk difference (Risk30(doxycycline) minus Risk30(azithromycin)); a negative RD indicates lower risk with the doxycycline strategy. The 95% CI uses sandwich variance (facility cluster-robust where available).
Key secondary outcomes
Secondary: (1) a composite of switching/adding a different agent on days 1-30 or primary retreatment (co-primary); (2) high-specificity retreatment (additionally requiring a chlamydia test claim within 7 days of the new prescription); (3) same-agent re-dispensing reported at 7-day and 14-day gaps; (4) interval-specific retreatment on days 8-20 and 21-30 with group-specific chlamydia testing rates; (5) new PID or epididymitis on days 1-30/1-90. Exploratory: recurrent-infection proxy on days 31-90/31-180. Sensitivity analyses: exposure definitions (100 mg BID x7 days only, 14 or more days only, by formulation, dispensing-confirmed only, broad phenotype, 180-day enrollment, full exclusion of gonococcal coinfection), IPCW, quantitative bias analysis, and negative controls. Subgroups: sex, age band, calendar period, facility type, department, gonococcal coinfection, and formulation.
Base
Study type
Observational
Study design
Basic design
Randomization
Randomization unit
Blinding
Control
Stratification
Dynamic allocation
Institution consideration
Blocking
Concealment
Intervention
No. of arms
Purpose of intervention
Type of intervention
Interventions/Control_1
Interventions/Control_2
Interventions/Control_3
Interventions/Control_4
Interventions/Control_5
Interventions/Control_6
Interventions/Control_7
Interventions/Control_8
Interventions/Control_9
Interventions/Control_10
Eligibility
Age-lower limit
| 15 | years-old | <= |
Age-upper limit
| 49 | years-old | >= |
Gender
Male and Female
Key inclusion criteria
(1) Treatment initiation at Day 0 with an eligible regimen (Strategy A: oral doxycycline, initial supply 7 or more days, daily dose 100-200 mg; or Strategy B: single-dose oral azithromycin). (2) Age 15-49 years. (3) No other oral anti-chlamydial drug and no same-day use of both strategies. (4) Outpatient index episode. (5) A non-suspect eligible chlamydia diagnosis (A56.0 group, etc.) from Day -14 to Day 0. (6) A chlamydia-specific test claim (nucleic acid or antigen; antibody testing not allowed) from Day -14 to Day 0. (7) No anti-chlamydial drug from Day -30 to Day -1 (new-user washout). (8) For women, no overlapping pregnancy episode. (9) No active complication (PID, epididymitis, LGV, etc.) from Day -7 to Day 0. (10) No extragenital infection (rectal, pharyngeal, ocular) from Day -14 to Day 0. (11) At least 365 days of continuous enrollment from Day -365 to Day 0. (12) Only the first eligible episode per person. The primary analytic period is 2014 Q1 to 2025 Q1. The primary population is men; women are a secondary population. JMDC insurer claims database (2005-2025) is used.
Key exclusion criteria
No treatment initiation with an eligible regimen. Age outside 15-49 years. Another oral anti-chlamydial drug or same-day use of both strategies. Inpatient index. Only a suspected diagnosis, or no eligible chlamydia test. Anti-chlamydial drug use from Day -30 to Day -1 (not a new user). Overlapping pregnancy episode in women. Active complication (PID, epididymitis, LGV, complicated chlamydia). Extragenital infection. Less than 365 days of continuous enrollment.
Target sample size
71272
Research contact person
Name of lead principal investigator
| 1st name | Satoshi |
| Middle name | |
| Last name | Kutsuna |
Organization
The University of Osaka, Graduate School of Medicine Faculty of Medicine
Division name
Department of Infection Prevention and Control
Zip code
565-0871
Address
2-2, Yamadaoka, Suita city
TEL
0836-6879-5111
kutsuna@hp-infect.med.osaka-u.ac.jp
Public contact
Name of contact person
| 1st name | Satoshi |
| Middle name | |
| Last name | Kutsuna |
Organization
The University of Osaka, Graduate School of Medicine Faculty of Medicine
Division name
Department of Infection Prevention and Control
Zip code
565-0871
Address
2-2, Yamadaoka, Suita city
TEL
0836-6879-5111
Homepage URL
kutsuna@hp-infect.med.osaka-u.ac.jp
Sponsor or person
Institute
The University of Osaka, Graduate School of Medicine Faculty of Medicine
Institute
Department
Personal name
Funding Source
Organization
The University of Osaka
Organization
Division
Category of Funding Organization
Self funding
Nationality of Funding Organization
Japan
Other related organizations
Co-sponsor
None
Name of secondary funder(s)
None
IRB Contact (For public release)
Organization
The University of Osaka Hospital, Ethical Review Board
Address
2-15, Yamadaoka, Suita city
Tel
0836-6879-5111
rinri@hp-crc.med.osaka-u.ac.jp
Secondary IDs
Secondary IDs
NO
Study ID_1
Org. issuing International ID_1
Study ID_2
Org. issuing International ID_2
IND to MHLW
Institutions
Institutions
大阪大学大学院医学系研究科 感染制御学 / The University of Osaka, Graduate School of Medicine
Other administrative information
Date of disclosure of the study information
| 2026 | Year | 08 | Month | 10 | Day |
Related information
URL releasing protocol
Publication of results
Unpublished
Result
URL related to results and publications
Number of participants that the trial has enrolled
Results
Results date posted
Results Delayed
Results Delay Reason
Date of the first journal publication of results
Baseline Characteristics
Participant flow
Adverse events
Outcome measures
Plan to share IPD
IPD sharing Plan description
Progress
Recruitment status
Preinitiation
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 | 08 | Month | 10 | Day |
Last follow-up date
| 2027 | Year | 03 | Month | 31 | Day |
Date of closure to data entry
Date trial data considered complete
Date analysis concluded
Other
Other related information
This is a target trial emulation (retrospective cohort) using the JMDC insurer claims database (January 2005 to May 2025, including the older database). For outpatient treatment of uncomplicated genital chlamydia infection, starting oral doxycycline (7 or more days) at Day 0 is compared with starting single-dose azithromycin, and the 30-day retreatment risk difference is estimated by propensity-score overlap weighting (ATO). The primary analytic period is 2014 Q1 to 2025 Q1 and the primary population is men. This is a prospective registration before analysis and without reference to outcomes (after Step 0 and outcome-blinded feasibility). Existing anonymized data are analysed after institutional review board approval.
Management information
Registered date
| 2026 | Year | 08 | Month | 10 | Day |
Last modified on
| 2026 | Year | 08 | Month | 10 | Day |
Link to view the page
Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000071588
