STROBE-NI (STROBE Extension for Newborn Infection)

What it is

— STROBE-NI (Strengthening the Reporting of Observational Studies in Epidemiology for Newborn Infection) is a reporting guideline that adds neonatal-infection-specific reporting items to the generic 22-item STROBE checklist for observational research. Published by Fitchett et al. in The Lancet Infectious Diseases in 2016 and developed by an international consensus group (the STROBE-NI working group), it is hosted and maintained as a STROBE extension within the EQUATOR Network. Its purpose is narrow and deliberate: studies of neonatal sepsis, meningitis, pneumonia, congenital and early/late-onset infection are notoriously hard to compare because authors use incompatible case definitions, ambiguous denominators, and inconsistent timing conventions. STROBE-NI forces authors to state, item by item, how cases were defined (clinically suspected vs laboratory/blood-culture-confirmed vs autopsy-confirmed), what the at-risk population and time origin were (live births, NICU admissions, age windows for early- vs late-onset disease), how specimens were collected and which pathogens were sought, and how infants were followed and lost. It is a reporting standard layered on top of STROBE — not a new study design, not an appraisal score, and not a conduct manual.

When to use

— Apply STROBE-NI when you are reporting an observational study (prospective or retrospective cohort, case-control, or surveillance/registry-based analysis) whose primary focus is infection in the newborn period: incidence or aetiology of neonatal sepsis/meningitis, risk factors, antimicrobial resistance surveillance, case-fatality, or related outcomes. It is the appropriate checklist for a peer-reviewed journal manuscript in neonatology, paediatric infectious disease, or global-health epidemiology, and for the analysis plan behind surveillance networks and birth-cohort studies. Decision rule for choosing the right family member: use plain STROBE for observational studies not centred on neonatal infection; use STROBE-NI when neonatal infection is the exposure/outcome of interest and the infection-specific items (case definition, denominator, timing, microbiology) are load-bearing; use RECORD / RECORD-PE when the data are routinely collected (claims, EHR, registries) and the database-provenance and code-list items dominate; use CONSORT/SPIRIT for interventional trials and their protocols. STROBE-NI and RECORD are not mutually exclusive — a routinely-collected neonatal-infection study can sensibly report against both, with RECORD covering data provenance and STROBE-NI covering the infection-definition items.

What it requires

— On top of the STROBE backbone (title/abstract, background, objectives, design, setting, participants, variables, data sources/measurement, bias, study size, statistical methods, results, limitations, generalisability, funding), STROBE-NI compels neonatal-infection specifics that are exactly the places RWE-style misclassification creeps in: an explicit, reproducible case definition stated separately for clinically suspected vs laboratory-confirmed infection, with the diagnostic algorithm and thresholds named (this is the phenotype/algorithm-validation problem in neonatal clothing); the denominator and time-zero convention (live births, admissions, person-time at risk; age cut-offs distinguishing early-onset from late-onset disease) so incidence is interpretable; specimen and laboratory methods (what was cultured/tested, contamination handling, pathogen panel) because culture-confirmation drives case ascertainment; gestational-age and birth-weight ascertainment, which govern both eligibility and confounding; completeness of follow-up and handling of competing/intercurrent events — neonatal mortality is both an outcome and a competing risk that truncates infection ascertainment; and transparent reporting of missing data and attrition, which is severe in neonatal cohorts (early death, transfer, discharge before outcome). The checklist requires that these be reported, making selective or vague definitions visible to a reviewer.

When NOT to use — limitations and common misapplications

— STROBE-NI is a reporting checklist; it is not a risk-of-bias instrument, not a quality score, and completing it does not make an observational neonatal-infection study unconfounded or causal. Concrete failure modes: (1) Wrong scope — using STROBE-NI for observational studies that are not about neonatal infection; those use plain STROBE. (2) Wrong family member — applying STROBE-NI to a study built on routinely-collected data without also satisfying RECORD/RECORD-PE, so data provenance, linkage, and code lists go unreported; or using a reporting checklist at all when an interventional trial demands CONSORT/SPIRIT. (3) Checklist-as-score — tallying completed items as a measure of study quality or risk of bias; appraisal of a non-randomized study is the job of ROBINS-I, not a completeness checklist. (4) Definition theatre — ticking the "case definition" item while the underlying microbiological/clinical algorithm is unvalidated (unknown sensitivity/PPV against blood culture or autopsy), which is precisely the misclassification STROBE-NI was created to surface. (5) Reporting ≠ conduct — a fully STROBE-NI-compliant paper can still have an immortal-time problem, an ill-defined denominator, or uncontrolled confounding; transparency is necessary, not sufficient.

How it maps to this catalog

— In this repo, STROBE-NI's substantive items are operationalised by these concepts, which tell a reviewer how to satisfy each requirement rather than merely report it: - The case-definition and pathogen-ascertainment items map to diagnosis-phenotype-algorithm-1ip-2op-time-window-rwe (constructing and time-windowing a confirmed vs clinical neonatal-infection phenotype) and to algorithm-validation (estimating the sensitivity/PPV of the case definition against blood-culture or autopsy gold standards — the quantitative backbone of an honest "case definition" item). - The denominator/time-zero, completeness-of-follow-up, and missing-data items map to attrition-and-loss-to-follow-up-rwe (early neonatal death, transfer, and discharge create severe, potentially informative loss) and to estimands-ate-att-intercurrent-events-rwe (neonatal mortality as a competing/intercurrent event that must be handled in the estimand, not ignored). - The generalisability item maps to generalizability-transportability-external-validity-rwe, which is acute for neonatal infection because aetiology, resistance, and case-fatality differ sharply between high-income NICU settings and LMIC community/facility births. - When the neonatal-infection study is built on routinely-collected data, claims-analysis and the data-fitness items it carries become relevant for provenance — but reported under RECORD, with STROBE-NI layered for the infection-definition items.

Applied note (surveillance / registry / linked RWE)

For a neonatal-infection surveillance birth cohort — e.g., a facility-based or community birth cohort in an LMIC with linked microbiology and vital records — STROBE-NI compliance means: state the denominator (live births vs admissions) and the early-/late-onset age windows explicitly; report the confirmed-vs-clinical case algorithm and its validation against culture or autopsy where available; report specimen/contamination handling and the pathogen panel; quantify loss to follow-up from early death, transfer, and discharge and treat it as potentially informative; and handle neonatal mortality as a competing event in the estimand rather than as simple censoring. Reporting these makes the difference between an incidence figure a reviewer can interpret and one that is silently incomparable across sites.