Draft synthesis: Acute pancreatitis with incretin-based… — submissions
The 10 submissions received, published in full with declared interests and secretariat responses.
§2Submissions and responses
10 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
This is a submission on the draft review of Do incretin-based therapies increase the incidence of acute pancreatitis?, made from a statistical standpoint.
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.
Studies not published in English were excluded without assessment
The respondent has read the draft synthesis on Do incretin-based therapies increase the incidence of acute pancreatitis? and makes one submission.
The respondent states that a language restriction was applied at screening and that for some of the compounds in scope a substantial literature is published in other languages.
The respondent proposes that the restriction be removed and the review re-run.
The secretariat accepts this submission in part. The restriction is removed prospectively and the records already excluded on language grounds have been retrieved and screened on title and abstract in translation. The full re-run proposed is not undertaken, and the limitation is recorded rather than concealed.
Language restriction is removed from the protocol for the series, the records previously excluded on that ground are listed with their screening outcome, and the residual limitation is stated in the abstract of this review.
Doses differing several-fold are pooled without examining dose-response
The respondent notes that the review question — Do incretin-based therapies increase the incidence of acute pancreatitis? — is answerable only if the contributing trials measured the same thing, and submits with that in view.
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.
This submission should be read alongside submission 002, which arises on the same draft.
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.
The review question is drawn too broadly to be answerable
The draft review of Do incretin-based therapies increase the incidence of acute pancreatitis? was read against its registered protocol.
The respondent states that the population as registered spans groups in which the intervention would be expected to behave differently, and that a single estimate across them is uninformative.
The respondent proposes that the question be split and the review re-registered.
The respondent has read submission 001 with interest and adds one observation the secretariat may find useful.
The secretariat does not accept this submission. The breadth was registered before screening, the pre-specified subgroups address the variation the respondent identifies, and re-registering after the results are known would convert a pre-specified analysis into a post hoc one.
The question stands as registered. The point is recorded in the limitations, and the assessment committee has noted it for the protocol of the next version of this review, which will be registered before the search is run. The submission remains published in full.
Declared interests should appear on the document rather than on a separate page
The respondent submits on the draft synthesis addressing Do incretin-based therapies increase the incidence of acute pancreatitis?. This submission concerns the methods rather than the conclusion, on the view that a conclusion is only as good as the search that produced it.
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.
Results at materially different follow-up durations are pooled
Having read the draft synthesis on Do incretin-based therapies increase the incidence of acute pancreatitis?, the respondent puts one point to the committee.
Contributing trials report the outcome at durations ranging across more than a year. The draft pools them into a single estimate. The respondent states that a mean at one duration and a mean at another are not estimates of the same quantity when the effect is still changing.
The respondent proposes that estimates be reported by duration band.
The respondent has read submission 001 and puts a further matter to the secretariat.
The secretariat accepts this submission. Pooling across durations assumes a plateau the contributing trials do not demonstrate.
Estimates are now reported by duration band, with the number of contributing trials and participants in each band stated, and no estimate is pooled across bands.
Two included studies do not meet the registered eligibility criteria
This submission concerns the draft review of Do incretin-based therapies increase the incidence of acute pancreatitis?. The respondent has conducted reviews on adjacent questions and the observation arises from that experience.
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 respondent notes that submission 002 has already been made and confines this submission to a matter not covered by it.
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.
Regulatory assessment documents were not searched
The respondent read the draft review of Do incretin-based therapies increase the incidence of acute pancreatitis? and has confined this submission to a single matter.
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.
References should carry a persistent identifier for every cited source
This submission addresses the draft synthesis on Do incretin-based therapies increase the incidence of acute pancreatitis? from the standpoint of a reader who will use the summary and not the appendices.
Several references in the draft carry a journal, a year and a volume but no persistent identifier. The respondent 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.
Submission 002 raises an adjacent matter. The respondent regards the two as separable and addresses only this one.
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.
The timepoint at which each outcome was extracted was chosen after the data were seen
The respondent’s comment on the draft review of Do incretin-based therapies increase the incidence of acute pancreatitis? arises from comparing the included set against the respondent’s own knowledge of the field.
The methods state that outcomes were extracted at the latest available timepoint. Several contributing trials report the same outcome at three timepoints, and taking the latest is a choice that can be made in the knowledge of what each shows.
The respondent proposes that the extraction timepoint be prespecified in the protocol, and that where it was not, the review report the estimate at every reported timepoint so that the choice is visible.
The secretariat accepts this submission. An extraction rule applied after the data are visible is a degree of freedom and should be recorded as one.
The extraction timepoint is now prespecified in the protocol for new reviews. Where a review predates the requirement, estimates are reported at every timepoint the contributing trials report.
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.