CARE (CAse REport guidelines)
A 13-item EQUATOR reporting checklist for transparent, complete write-up of a single clinical case report (or small case series), centered on a structured patient timeline. It is a reporting tool, not a design, risk-of-bias, or causal-inference instrument.
What it is
The CARE (CAse REport) guidelines are a 13-item reporting checklist for clinical case reports, developed by consensus in 2013 (Gagnier et al.) and elaborated in 2017 (Riley et al.). CARE is hosted by the EQUATOR Network alongside its sibling reporting guidelines (STROBE, CONSORT, PRISMA, STARD). Its purpose is narrow and specific: to make the narrative of a single patient (or a very small series) transparent and complete enough that a reader can judge what happened, in what order, and why the author believes the case is informative. The signature CARE item is the timeline — a chronological figure or table that aligns presentation, diagnostics, interventions, and outcomes — which is what distinguishes a disciplined case report from an anecdote. The checklist also covers title, key words, abstract, introduction, de-identified patient information, clinical findings, diagnostic assessment (and diagnostic challenges), therapeutic intervention, follow-up and outcomes, discussion (strengths/limitations against the literature), patient perspective, and informed consent. CARE governs how a case is written up; it makes no claim about study validity, effect estimation, or generalizability.
When to use
Use CARE when the unit of evidence is a clinical narrative about one patient (occasionally a handful): an unexpected adverse drug event, a novel presentation, an unusual response to therapy, a rare disease, or a diagnostic puzzle. The primary decision context is peer-reviewed journal submission — most journals that publish case reports now request the CARE checklist. Decision rule for choosing CARE versus a sibling guideline: if the report describes one patient's clinical course as a story, CARE applies. The moment the design involves a defined cohort, comparison group, denominator, or analytic estimate — even a descriptive multi-patient series analyzed as data — you have left CARE's scope and entered STROBE/RECORD/MOOSE territory. If the case is an individual adverse-drug-reaction report destined for a pharmacovigilance system or a regulatory safety database, the governing framework is ICH E2D / CIOMS / GVP, not CARE, although CARE's timeline discipline still improves the narrative.
What it requires
CARE enforces narrative completeness and chronological transparency rather than analytic rigor. The substantive item groups that matter most: - Structured timeline (the defining item): a chronological alignment of symptom onset, encounters, diagnostics, interventions (with dates, doses, durations), and outcomes — the single best defense against post-hoc storytelling. - Diagnostic assessment and challenges: the tests performed, differential diagnosis, reasoning, and what made the diagnosis difficult — so a reader can appraise diagnostic certainty. - Therapeutic intervention and outcomes with follow-up: exactly what was given and what followed, including adverse events and the duration and completeness of follow-up. - Discussion against the literature: why this case adds knowledge, and an explicit statement of limitations — crucially, the inferential limits of an n-of-1 observation. - De-identification, informed consent, and patient perspective: ethical and patient-centered reporting requirements. For a case identified or assembled from an EHR, CARE-quality reporting demands that the chart-derived timeline be reconstructed faithfully (encounter dates, medication start/stop, lab values) rather than summarized loosely.
When NOT to use — limitations and common misapplications
- CARE is a reporting checklist, NOT a risk-of-bias tool and NOT a quality score. A fully completed CARE checklist says the report is transparent, not that the case is valid or that any inference from it is sound. There is no total score. - A single case cannot support a causal or comparative claim. With n=1 there is no comparator, no denominator, and no control of confounding; CARE compliance does nothing to license "Drug X caused Y" or "X is more effective than Z." Treating a polished case report as causal evidence is the most common and most damaging misuse. - Wrong unit / wrong guideline. A case series analyzed as multi-patient data is observational research and should be reported under STROBE (or RECORD/RECORD-PE for routinely collected health data, MOOSE for synthesis), not CARE. Using CARE to dress up a small cohort hides the absence of a denominator and design. - Pharmacovigilance confusion. An individual case safety report (ICSR) for a suspected adverse drug reaction is governed by ICH E2D / CIOMS / EMA GVP causality and minimum-criteria conventions; CARE is not a pharmacovigilance standard and should not be substituted for one in a safety submission. - Checklist-as-theater. Submitting the CARE checklist while omitting the timeline figure, dates, doses, or consent defeats the purpose; the timeline in particular is frequently the missing item that reviewers should demand.
How it maps to this catalog
CARE sits at the descriptive, hypothesis-generating edge of the evidence hierarchy, so most analytic RWE concepts in this catalog do not implement it — and saying so plainly is part of using CARE correctly. The genuinely relevant cross-references are narrow: - case-report — the study-type concept CARE directly governs; start here. - case-series and descriptive-epidemiology-rwe — the adjacent designs you move to when the unit becomes multiple patients, at which point STROBE (not CARE) is the reporting guideline. - endpoint-adjudication-chart-review-rwe — the chart-review discipline that underpins a faithful CARE diagnostic assessment and timeline when the case is reconstructed from records. - safety-signal-case-definition-rwe — relevant when a case report seeds a pharmacovigilance signal; note the handoff to ICH E2D/CIOMS for the formal ICSR. - diagnosis-phenotype-algorithm-1ip-2op-time-window-rwe — applicable only in the narrow situation where an EHR phenotype was used to surface the index case; this is a genuine stretch and should be cited as such, not as a core requirement. CARE does not map to target-trial emulation, propensity scores, hdPS, estimands, or active-comparator designs — those require comparison groups CARE explicitly lacks.
Applied note (EHR/chart-based case reports)
When a case is drawn from an electronic record, CARE's value is forcing a defensible timeline: pin each event to a source date (encounter, order, fill, lab result), distinguish ordered from administered therapy, and reconcile discrepant dates before narrating causation. The same chart-review rigor used for outcome adjudication in cohort RWE is what makes an EHR-sourced case report trustworthy — but it remains a single observation, and the discussion must say so.