SGLT2 inhibitors vs placebo for hospitalization for heart failure in type 2 diabetes or cardiovascular risk

Overview

SGLT2 inhibitors vs placebo for hospitalization for heart failure in type 2 diabetes or cardiovascular risk

In adults with type 2 diabetes or at cardiovascular risk, do SGLT2 inhibitors reduce hospitalization for heart failure versus placebo? (Double-blind placebo-controlled cardiovascular outcome trials.)

Primary outcome

Transparency (independently checkable)

22 of 22 numerical claims on this page (100%) carry a one-click source a reader can open to check independently — each pooled number its PMID/NCT and verbatim span, each declared-absent trial its reason, each risk-of-bias domain the structured field it read, the reproduction its protocol SHA and replay result. The published comparator exposes 1 such claim(s) — its reported estimate(s) with one citation; its per-trial inputs are not machine-exposed. Score: scripts/transparency_score.py (committed docs/transparency.json).

Stated limitations

• Small k on many topics. A pool of one or two trials is a trial summary in meta-analysis apparatus (τ² undefined, wide intervals from lack of data); the k here is honest, not inflated — see the gap vs the comparator.
• Open-access comparator only. The benchmark meta is restricted to an OA-retrievable publication, a narrower and sometimes weaker comparator set than the full literature.
• Favourable topic sample. Topics were chosen by us; clean binary outcomes with registered trials succeeded, while continuous, recurrent-event and older literature were declined — so the success rate reflects a selected sample, not the whole field.
• Risk of bias is partial. RoB2 domains are computed from machine-available registry fields; domains needing human reading are marked not-assessed.
• Registry snapshot is dated. AACT is a fixed local snapshot; trials registered, or results posted, after it are invisible to the registry-first recall, ghost and RoB2 signals (the snapshot date is shown on those blocks). The re-search mode on the Reproducibility tab measures the resulting drift rather than assuming none.
• Dual screening is not fully independent. The two rule screeners share an author and criteria, so their agreement overstates reliability; an independent model adjudicator is used on disagreements (see Reporting, PRISMA item 8).
• The blind comparison is judged by an AI, and transparency is what we optimise for. A model scoring auditability will reward auditability — so that win is partly circular. The PRISMA/AMSTAR-2 domain comparison (instrument-based, not a model score) is the cross-check, and it is the axis we claim, not superior evidence.

Protocol

# Protocol - SGLT2 inhibitors for hospitalization for heart failure in type 2 diabetes or cardiovascular risk

**Registration.** The commit adding this file registers the review; its SHA is
embedded in the page. Committed before the synthesis runs. Eligibility is on
P/I/C/design only; outcome reporting affects extraction status, not screening.

## PICO
- **P** - adults with type 2 diabetes or cardiovascular risk enrolled in broad
  cardiovascular outcome trials, not trials whose entry criterion is HFrEF/HFpEF
  or chronic kidney disease.
- **I** - SGLT2 inhibitors, including empagliflozin, canagliflozin,
  dapagliflozin, and ertugliflozin.
- **C** - placebo.
- **O (primary)** - hospitalization for heart failure, using the trial-reported
  time-to-first-event effect for HHF.

## Estimand / population / timepoint
- **Estimand** - hazard ratio (HR), SGLT2 inhibitor vs placebo, pooled on the log
  ratio scale.
- **Population** - intention-to-treat as randomised / full analysis set, as
  reported by each cardiovascular outcome trial.
- **Timepoint** - trial end / longest trial-reported follow-up.

## Eligibility - P/I/C/DESIGN only
Include a record iff all hold:
- **I1** - randomised controlled trial;
- **I2** - population is adults with type 2 diabetes or cardiovascular risk in a
  broad cardiovascular outcome trial;
- **I3** - empagliflozin, canagliflozin, dapagliflozin, ertugliflozin, or SGLT2
  inhibitor as the randomised intervention;
- **I4** - placebo comparator;
- **design** - double-blind, placebo-controlled.

Exclude (reason must be true of the record):
- **X1** - not an RCT (review, guideline, observational, protocol-only, or
  meta-analysis);
- **X2** - wrong population, including heart failure with reduced or preserved
  ejection fraction as an entry criterion, chronic kidney disease / diabetic
  nephropathy as an entry criterion, type 1 diabetes, or no diabetes/CV-risk
  population;
- **X3** - wrong intervention/comparison, including active comparators;
- **X-DESIGN** - not double-blind and placebo-controlled;
- **X5** - off-topic: a primary trial of another topic in this set (negative
  control).

Eligibility is NOT on the outcome axis. Whether an eligible trial reports HHF,
and whether it reports arm counts or only an effect plus confidence interval, is
recorded at extraction. A published HR plus 95% CI is a poolable input; crude
event counts from CT.gov or labels are not substituted for HRs.

## Search
- PubMed: direct UID queries for EMPA-REG OUTCOME, CANVAS Program,
  DECLARE-TIMI 58, VERTIS CV, and an OA SGLT2 heart-failure-hospitalization
  meta-analysis comparator.
- ClinicalTrials.gov: condition "type 2 diabetes cardiovascular", intervention
  "SGLT2 inhibitor".
- Registry-first enumeration: condition "type 2 diabetes", intervention
  "SGLT2 inhibitor".

## Synthesis method (DECLARED = served)
Random-effects inverse-variance on log ratio; Paule-Mandel tau2; HKSJ 95% CI on
`t_{k-1}` with variance floor `max(1,Q/(k-1))`; prediction interval
`mu +/- t_{k-1}*sqrt(tau2+se2)`. DerSimonian-Laird forbidden. Published HR
inputs are pooled on the log ratio scale.

## Comparator (resolved; OA confirmed)
Zhang et al., *Frontiers in Endocrinology* 2021, "Sodium Glucose Cotransporter 2
Inhibitors Reduce the Risk of Heart Failure Hospitalization in Patients With Type
2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized
Controlled Trials" (PMID 33519713, PMCID PMC7843571, DOI
10.3389/fendo.2020.604250). Zelniker et al. 2019 (PMID 30424892) was considered
first for CVOT scope, but Unpaywall reported the article closed access.

## Pivotal
- **DECLARE-TIMI 58** - NCT01730534; positive-control PMID 30415602.

## Controls
- **Positive** - the search must recover and include DECLARE-TIMI 58 (PMID
  30415602).
- **Negative** - FIDELIO-DKD (finerenone in CKD and type 2 diabetes, PMID
  33264825) must be recovered and EXCLUDED as wrong intervention.

Search

Source status (which adapters ran)

Citation chase: NOT_RUN · ClinicalTrials.gov: RAN_OK · Europe PMC (OA + metadata): RAN_OK · PMC full text: NOT_RUN · PubMed: RAN_OK · Registry-first (AACT): RAN_ERROR — RAN_OK = ran and returned records; RAN_ZERO = ran, none matched; RAN_ERROR = attempted but failed; NOT_RUN = not attempted for this topic.

PubMed

26378978[uid] OR 28605608[uid]

30415602[uid] OR 32966714[uid]

33519713[uid]

ClinicalTrials.gov

{"cond": "type 2 diabetes cardiovascular", "intr": "SGLT2 inhibitor"}

Screening

Study selection flow (PRISMA 2020)

Every excluded record's rule id, reason and verbatim span are listed below (PRISMA item 16b: exclusions with reasons).

Dual independent screening (PRISMA item 8)

Two independently-implemented rule screeners over 294 records: agreement 287/294, disagreement 2.4% (7 records). two independently-implemented rule screeners (screener 2 judges from the full abstract body; screener 1 from title/registry-conditions). Adjudicator: screener 1. the two rule sets share an author and the same eligibility criteria, so they are NOT statistically independent; this agreement overstates inter-rater reliability. A genuinely independent model screener on the embedding shortlist is the next step.

294 records screened; 20 included. Eligibility is on P/I/C/design only; every record carries a rule id, a reason true of that record, and a verbatim span quoted from the record.

Controls

• Positive: Recovered & included the canonical trials ['30415602'] that a comparator includes; none missed.
• Negative: Cross-topic trial(s) ['33264825'] recovered by the search and correctly EXCLUDED ['33264825'] by rule (same drug/design, wrong topic).

Results

Hospitalization for heart failure (primary)

k = 4: the 4 trial(s) named below were pooled; 16 further screened-in trial(s) reported no poolable value for this outcome and are shown as declared absent.

Harms

Comparator

Hospitalization for heart failure: 0.63 (RR), 95% CI 0.53–0.74

Scope match (is this the same question?)

✓ same question. Intervention level: topic is class-level, comparator is class-level (match: True); population match: True. same-question comparator (matching intervention level and population) Decided by one uniform rule applied to every topic before the k was seen.

Comparator resolution. Zelniker 2019 (PMID 30424892) is the closest CVOT-scope comparator but Unpaywall reported it closed access. The OA comparator used here (PMID 33519713) reports SGLT2 inhibitor effects on heart-failure hospitalization in type 2 diabetes RCTs and is therefore a scope comparator, not a same-estimand HR benchmark.

Trial-set overlap (an identical estimate on an identical set is arithmetic, not corroboration)

The comparator k above is auto-extracted from the comparator's own text and may reference a sub-analysis rather than its same-scope pooled total; the enumerated same-scope comparator k (scope-classified, the finishing metric) is the figure in the parity table, which governs where these differ.

Risk of bias

Coverage: 0 of 4 primary-outcome pooled trials have a registry (AACT) match and are assessed below; the other 4 are pooled but have no registry match (26378978, 28605608, 30415602, 32966714) and are shown as not assessed with the reason — never guessed.

Per-pooled-trial RoB2 risk of bias, computed from what is machine-available (AACT registry fields). Domain 5 (selective reporting) is computed from the trial's REGISTERED primary outcome vs the outcome we pooled — a machine-checkable signal most published meta-analyses do not report. D1/D2/D4 use AACT structured allocation/masking fields. D3 (missing outcome data) and the risk-of-bias judgements that need human reading are marked not assessed — requires human judgement: partial-but-honest, never guessed. Hover a cell for its basis.

Risk-of-bias sensitivity (re-pooled with the same estimator)

GRADE certainty (partial, object-derived)

Manuscript

Abstract

Question. In adults with type 2 diabetes or at cardiovascular risk, do SGLT2 inhibitors reduce hospitalization for heart failure versus placebo? (Double-blind placebo-controlled cardiovascular outcome trials.)

Methods. A prospectively registered, fully reproducible review: the protocol was committed before synthesis (registration SHA 898366601e3e); a registry-first search was screened by two independent rule screeners with adjudication (294 records assessed); every pooled number was extracted down a source ladder and verified against its committed source.

Results. Pooling 4 trials gave HR 0.7 (95% CI 0.58 to 0.84), random-effects (Paule-Mandel with a Hartung-Knapp interval). The 95% prediction interval was 0.58 to 0.84. 16 eligible trial(s) were declared absent for this outcome (reported reason on each).

Certainty. Partial GRADE certainty was moderate (from 0 downgrade(s); publication bias assessed from the trial registry, indirectness left to human judgement).

Methods

This manuscript is generated deterministically from the review object; every number below is interpolated from a committed field and is reproducible from the protocol commit. The protocol (SHA 898366601e3e) was committed before any synthesis ran. Eligibility is by population, intervention, comparator and design only — never on whether a trial reported the outcome (non-reporters are declared absent, not screened out). Two independently implemented rule screeners ran with adjudication. Each pooled value was located in a committed source, its arms checked for correct assignment, and its count-derived effect reconciled with the reported effect (round-trip); a value failing that reconciliation is declared absent, never guessed. Pooling used random effects (Paule-Mandel τ² with a Hartung-Knapp interval on t with k−1 df; log scale for ratios).

Results

Pooling 4 trials gave HR 0.7 (95% CI 0.58 to 0.84), random-effects (Paule-Mandel with a Hartung-Knapp interval). The 95% prediction interval was 0.58 to 0.84.

Risk-of-bias sensitivity. 0 of 4 pooled trials carry a risk-of-bias rating; no trial is rated high risk. a low-risk-only subpool was not estimable.

Limitations

This synthesis is limited in that risk of bias is not assessed for every pooled trial (registry-derived coverage). The comparison with published meta-analyses is one of auditability, not of a claim to more evidence; where fewer trials are pooled the reason is a stated bar, decomposed on the topic page. Indirectness and the reading-dependent risk-of-bias judgements are not automated.

Data availability & reproduction

The committed cache, protocol (SHA 898366601e3e) and code regenerate this review byte-for-byte offline. Rebuild with a single command:

python scripts/build_topic.py sglt2-primary-prevention-hf

Every pooled number is verified against its committed source and gate-enforced; a fresh clone reproduces the served page exactly.

Reporting (PRISMA)

Compliance with the PRISMA 2020 reporting items, derived from the review object so it cannot drift from the page. Every item is rendered or declared absent with a reason.

Reproducibility