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Protocol templates → Active-comparator new-user

Multi-national ACNU protocol builder

Active-comparator new-user design under a target trial emulation framework. The active comparator behaves as an 'emulated placebo' from the same therapeutic context; minimising confounding by indication and addressing immortal-time / prevalent-user bias. Tick the boxes for the operational pieces; export as Word (.docx) or Markdown.

← All designs
1 · Study identification
2 · Research question (one-line summary)
3 · Sites

Tick every database (not just country) you want to include. The feature chips next to each show what each database can support; only tick a site whose features cover what your outcome / exposure / covariates need (e.g., a lab-defined outcome needs Lab; an all-cause mortality endpoint needs Mor).

Legend Rx Prescriptions Dx Diagnoses Lab Lab results Img Imaging Mor Mortality linkage Can Cancer-registry linkage Preg Pregnancy / birth linkage Gen Genomics / biobank linkage

Taiwan

South Korea

Japan

Hong Kong

Australia

Finland

United Kingdom

Netherlands

United States

4 · Cohort definition
Indication / cohort entry condition

Inclusion criteria; tick those to apply

Exclusion criteria; tick those to apply

5 · Exposure & comparator
6 · Outcome ascertainment
Fills definition + codes. Each row says whether this library carries a validation study for it — most do not. Where one exists it is added to the References section on export, and withdrawn again if the definition here stops being the one that was picked.

Secondary outcomes; tick those to include

7 · Follow-up & censoring

Censoring rules; tick those that apply

8 · Confounding control
Auto-fills the method, its operational details, and adds the method citation to References on export — the citation is withdrawn again if you change the method afterwards.

Baseline covariates; tick those to adjust for

Demographics

Comorbidities (binary, ever in look-back)

Medications (binary, dispensed in look-back)

Healthcare utilisation

Clinical / lab (where available)

8b · Propensity-score calibration · correcting a claims study with a richer validation sample

A claims database records diagnoses, procedures, dispensings and demographics; it does not record lab values, vitals, imaging measurements, severity scores or lifestyle. A propensity score fitted there is therefore error-prone. If you also have a smaller dataset holding both the claims variables and the missing clinical ones, you can fit a gold-standard propensity score in it, learn how the two relate, and correct the large study's effect estimate. That is propensity-score calibration — regression calibration with the propensity score as the mismeasured covariate (Stürmer T, Schneeweiss S, Avorn J, Glynn RJ. Am J Epidemiol 2005;162(3):279-89). The fitted equation is the deliverable: a later claims-only study can cite it and apply it without repeating the validation work.

Where the numbers come from. This is a protocol builder — it holds no data and imports none. Every coefficient below is the output of fitting two propensity models in your validation dataset: an error-prone score from the claims variables alone, and a gold-standard score from those plus the clinical ones. Fit them wherever you like, or use RWE Studio, which runs real R in your browser on a dataset that never leaves it and can emit a calibration handoff file you import here instead of retyping a dozen numbers. The treatment coefficients from the claims-only study are the one thing no validation dataset can supply — those stay hand-entered.

Import a calibration handoff (JSON)

A small metadata-and-model-output file from RWE Studio (kind: "rwe-studio/psc-handoff"). It carries the two variable lists, the PS scale, α₀/α₁/α₂ with standard errors, R², and the surrogacy result — never rows or cell values. A payload containing anything row-shaped is refused.

Which covariates does the claims database actually have?

Every covariate ticked in Section 8, plus anything you add below. Click a chip to move a variable between the two propensity scores. Claims variables go into both scores; clinical-only variables go into the gold-standard score alone; exclude drops identifiers, outcomes and post-baseline measurements from both.

The keyword rule is only a starting position, and it is wrong often enough to matter. It reads variable names, so it cannot tell a measurement from a billing code, and it misses instruments it has never seen. Run Let AI classify and check every row it marks AI changed — a clinical variable left in the claims list quietly collapses the correction to zero, which looks exactly like "no unmeasured confounding".

What the AI button sends. Variable names from Section 8 and from the two boxes below, your codebook notes, the name of the claims database, and the four research-question fields (population, exposure, comparator, outcome) — all of it verbatim. Nothing else leaves the browser: no patient data, no rows, no values. Keep patient-identifiable text out of every one of those fields.

Step 0 · The surrogacy test — do this before you trust any correction

Calibration only works if the claims-only score carries no information about the outcome beyond the gold-standard score. Wan (Am J Epidemiol 2024) shows this holds only when the covariates' effects on the outcome are proportional to their effects on treatment; otherwise the correction is biased and can be worse than doing nothing. If your validation dataset has outcomes, measure it.

The measure to use is S, from Lunt et al. (Am J Epidemiol 2012, Table 2 footnote g): of the outcome variation explained by both propensity scores together, the percentage attributable to the gold-standard score alone. 100% means perfect surrogacy. It is a ratio of two likelihood-ratio statistics and the R code below computes it. Prefer it to a p-value — in a validation sample of any size the p-value rejects on departures far too small to matter, and our own simulation found it rejecting at S = 92.5% where calibration still removed most of the bias.

Anchors, from Lunt's published Table 2: scenarios with S of 88-99% gave 75-114% bias reduction, while S of 6-14% gave bias reduction of −132% to −189% — calibration made things substantially worse. In our own simulation PSC helped at S ≥ 92% (5/5 replicates) and hurt at S ≈ 82% (0/5). The bands this tool uses are a reading of those two sources, not a published cut-off.

Fitted coefficients (fill in once the validation analysis has run)

From the calibration model PS_gs ~ PS_ep + treatment in the validation dataset, and from the claims outcome model outcome ~ treatment + PS_ep. Leave blank at the protocol stage — the section still exports with the equation in symbolic form.

Interval for the calibrated estimate. There is no reliable closed-form interval here: the correction is a ratio of estimated coefficients from two models fitted in two samples. Run the bootstrap in the generated R code and paste the percentile bounds below — on the same scale as β̂ (log HR / log RR), not as a ratio. Left blank, the protocol reports a point estimate with no interval, which is the honest default.

9 · Statistical analysis

Subgroup analyses; tick those to perform

Sensitivity analyses; tick those to include

10 · Execution & timeline

Timeline preset

11 · Ethics, dissemination, references (optional)

Consistency checks · target-trial 防呆

Study design diagram

Covariate look-back(s), new-user washout, and follow-up windows relative to the index date. Drag the ● handles to adjust; list per-covariate look-backs to get a separate draggable window for each, like the clone builder.