Draft synthesis: glucagon-like peptide-1 receptor agonists… — submissions
The 15 submissions received, published in full with declared interests and secretariat responses.
§2Submissions and responses
15 submissions were received. Each is published in full below with its declared interest, the secretariat response and the disposition. The Institute publishes submissions it did not accept in the same form as those it did.
A single-trial result is presented in the visual form of a pooled estimate
An outcome contributed by one trial is presented in the same forest plot format as outcomes contributed by several. The respondent states that the format carries an implication of replication that a single trial does not have.
The respondent proposes that single-trial outcomes be presented differently and labelled as unreplicated.
The secretariat accepts this submission. The form of a graphic is part of what it asserts.
Outcomes contributed by a single trial are now reported without a pooled diamond, labelled as unreplicated, and downgraded for imprecision or inconsistency according to the framework rather than presented as a synthesis.
The review protocol is described but its registration record is not linked
The respondent asks for the prospective registration record of the review protocol so that the registered outcomes can be compared with the reported ones.
The respondent states that without it the claim of prospective registration cannot be checked.
The secretariat accepts this submission in part. The protocol is published in full on the Institute site with its version history, which permits the comparison the respondent asks for. Where an external registration identifier is not held by the Institute, the review says so rather than supplying one.
Each synthesis now links its own protocol with the version in force at screening, and states explicitly where an external registration identifier is not held, so that the absence is a recorded fact.
References should carry a persistent identifier for every cited source
Several references in the draft carry a journal, a year and a volume but no persistent identifier. The respondent, who works in a library setting, states that retrieval of such a reference is materially slower and that identifiers should be supplied throughout.
The respondent asks in the alternative that where an identifier exists but is not carried, the omission be explained rather than left as a gap the reader must interpret.
The secretariat accepts the second limb of this submission and declines the first. Identifiers are supplied wherever the Institute holds one. Where the Institute does not hold an identifier it will not supply one, because a reconstructed identifier that resolves to the wrong record is a worse defect than an absent one.
Every reference without a persistent identifier now carries an explicit statement that the identifier is not held by the Institute, so that its absence is a recorded fact rather than an apparent oversight.
Declared interests should appear on the document rather than on a separate page
The draft links to a central conflicts register. The respondent argues that a reader assessing whether to rely on a particular document should not have to leave it to find out who assessed it and what they declared.
The respondent proposes that the interests of every named contributor to a document be printed on that document.
The secretariat notes this submission and records that the draft already provides for it, which the respondent could reasonably have missed because the provision sits in an appendix.
Every document carries the declared interests of its named contributors in its front matter, and the central register exists so that a reader can see a person across all documents rather than one at a time. No amendment arises; the provision has been moved from the appendix into the body of the methodology document so that it is findable.
The same concern is used to downgrade in two domains
The draft downgrades for both indirectness and imprecision citing the same feature of the contributing trials. The respondent states that this double-counts a single concern and produces a rating lower than the framework supports.
The respondent proposes that the rating be raised by one level.
The secretariat accepts this submission in part. The double count is real in one of the two outcomes identified and not in the other, where the two domains rest on different features.
The rating for the first outcome has been raised by one level and the domain reasoning restated, and the reasoning for the second has been rewritten to make clear that the two downgrades rest on different features of the evidence.
Doses differing several-fold are pooled without examining dose-response
Contributing trials administer doses that differ by a factor of several. The draft pools them and reports one estimate. The respondent states that where a dose-response relationship exists the pooled figure corresponds to no dose that anyone receives.
The respondent proposes that estimates be reported by dose and that dose-response be examined where the data allow.
The secretariat accepts this submission. A pooled estimate across doses is an estimate for an average dose that no protocol specifies.
Estimates are now reported by dose group, a dose-response examination is reported where three or more dose levels contribute, and the pooled across-dose estimate is removed rather than retained alongside.
Two included studies do not meet the registered eligibility criteria
The respondent identifies two studies in the included set whose duration falls below the minimum stated in the protocol, and one excluded study that appears to meet every criterion.
The respondent proposes that the three be reassessed and that the outcome of the reassessment be recorded whichever way it goes.
The secretariat accepts this submission in part. On reassessment, one of the two included studies does fall below the minimum duration and has been removed. The second reports a duration that met the criterion in the protocol version registered at the time. The excluded study was excluded for a reason not clearly recorded, which was a documentation failure.
One study has been removed from the included set and the estimate recomputed, the exclusion reason for the third study has been corrected in the excluded-studies table, and the screening decisions are now recorded against the protocol version in force at the time of screening.
The document set should be published in translation
The respondent notes that the assessments concern compounds supplied internationally and that publishing only in English restricts access to the assessment to readers who work in it.
The respondent proposes machine translation of the document set as an interim measure, with human review of the certainty language.
The secretariat does not accept this submission, and records that the underlying point is sound and that the proposed remedy is the difficulty.
A translation whose certainty language has drifted is a different assessment carrying the Institute's name, and the Institute cannot review translations it does not have the capacity to review. The documents remain in English. The submission is published in full because the access problem it identifies is real and unresolved.
Risk-of-bias judgements are reported as an overall rating without the domains
The draft reports a single overall risk-of-bias judgement per study. The respondent states that the overall judgement conceals which domain drove it, and that a reader assessing whether the concern applies to their question needs the domain.
The respondent proposes a domain-level table with the supporting quotation for each judgement.
The secretariat accepts this submission. The overall judgement is a summary of the domains and publishing only the summary makes it uncheckable.
Risk of bias is now reported at domain level for every included study, with the text on which each judgement was based quoted and referenced, and the overall judgement derived from the domains rather than asserted alongside them.
Regulatory assessment documents were not searched
The respondent states that regulatory assessment reports frequently contain analyses that never appear in journals, and that a search limited to bibliographic databases will miss them.
The respondent proposes that regulatory documents be searched for every review in the series.
The secretariat accepts this submission in part. Regulatory assessment documents are searched. The proposal that they be treated as equivalent to a full study report is declined, because the level of detail varies and is often insufficient for risk-of-bias assessment.
Published regulatory assessment documents are now searched as a named source, are reported as a distinct evidence class in the included-studies table, and contribute to the assessment while being excluded from pooled estimates where risk of bias could not be assessed from the document.
Point estimates are given without an interval
Several estimates in the draft appear as single figures. The respondent states that a point estimate without an interval invites a precision the underlying data do not support, and that the effect is worst where the estimate is drawn from a small contributing set.
The respondent proposes that no point estimate appear anywhere in the document set without its interval, including in summary tables and in the abstract.
The secretariat accepts this submission in part. Intervals are added wherever the source reports one. The proposal is declined for figures the source published without an interval, because the Institute will not compute an interval a source did not report.
Every estimate now carries its interval where the source reported one, and where it did not, the estimate is annotated as reported without an interval rather than left to appear as a precise figure.
The conclusion is stated more strongly than the certainty rating supports
The draft rates the anchor outcome at low certainty and then states in the conclusion that the intervention is effective. The respondent states that the two sentences cannot both be true as written.
The respondent proposes that conclusion language be tied mechanically to the certainty rating, so that a low rating cannot produce an unqualified claim.
The secretariat accepts this submission. The mismatch is the failure mode the certainty framework exists to prevent.
Conclusion wording is now drawn from a fixed set of formulations tied to the certainty rating, so that a low certainty rating produces a statement that the evidence may suggest an effect and that the estimate is likely to change with further research.
Subgroup findings are reported that were not registered in the protocol
The draft reports differences between subgroups that do not appear in the registered protocol. The respondent states that unregistered subgroup analysis is hypothesis-generating and that the draft presents it in the same form as the pre-specified results.
The respondent proposes that unregistered analyses be removed.
The secretariat accepts this submission in part. The analyses are retained and relabelled rather than removed, because removing an analysis that was conducted leaves no record that it was.
Every subgroup analysis is now labelled as pre-specified or post hoc against the registered protocol, post hoc analyses are reported in a separate subsection without a certainty rating, and the protocol version against which the labelling was made is stated.
Patient-reported outcomes are collected by the trials and not reported by the review
The respondent, a trustee of a patient organisation, states that several contributing trials measured quality of life and function and that the review reports neither, having selected outcomes on the basis of what could be pooled.
The respondent proposes that these outcomes be reported narratively where they cannot be pooled.
The secretariat accepts this submission in part. The outcomes are reported narratively. The proposal to pool them is declined because the instruments used are not comparable and pooling would produce a figure with no interpretation.
Patient-reported outcomes measured by any contributing trial are now reported narratively by instrument, with the instrument named and its minimum important difference stated where one is published, and the absence of a pooled estimate explained.
Registered trials that never reported are not counted anywhere in the review
The respondent states that the screening flow accounts for records retrieved and excluded but does not record registered trials identified with no posted result, which are neither included nor excluded and simply disappear.
The respondent proposes that they be counted and reported as a category, with the proportion of the registered evidence base they represent.
The secretariat accepts this submission. A review that cannot say how much of the evidence base is unreported cannot say how much weight its own estimate deserves.
Registered trials without posted results are now identified, counted and reported as a distinct category in the screening flow, with the proportion of registered participants they represent stated in the limitations.
References cited on this page
References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.
- International Organization for Standardization. ISO/IEC 17025:2017 General Requirements for the Competence of Testing and Calibration Laboratories. ISO/IEC Standard 2017;3rd edition. identifier not held by the Institute
Identifiers are reproduced only where the Institute holds them. Where a digital object identifier or PubMed identifier is not shown, the Institute has recorded the journal and year and has not constructed an identifier.