Draft synthesis: Nationally registered neuropeptides and the… — submissions
The 16 submissions received, published in full with declared interests and secretariat responses.
§2Submissions and responses
16 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.
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.
A surrogate outcome is used as the anchor without validation evidence
The anchor outcome in the draft is a surrogate. The respondent states that the relationship between the surrogate and the outcome a decision turns on is itself an evidential question, and that the draft assumes it.
The respondent proposes that no surrogate serve as an anchor.
The secretariat accepts this submission in part. The anchor is retained where the surrogate is the only outcome the contributing trials measured, and the validation question is addressed rather than assumed.
Where the anchor is a surrogate, the synthesis now states the evidence for the surrogate relationship, rates it separately, and downgrades the anchor rating for indirectness accordingly rather than carrying the surrogate as though it were the outcome of interest.
An indirect comparison is presented without an assessment of transitivity
The draft compares two interventions through a common comparator. The respondent states that the trials contributing to each side differ in background therapy and in baseline severity, and that the resulting estimate assumes a similarity the draft does not test.
The respondent proposes that transitivity be assessed explicitly and reported before any indirect estimate is presented.
The secretariat accepts this submission. An indirect estimate presented without a transitivity assessment invites a reader to treat an assumption as a result.
Transitivity is now assessed against a stated list of effect modifiers and reported before any indirect estimate, and where the assessment fails the contrast is reported as unestimable with the reason rather than estimated with a caveat.
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.
A funnel plot is presented for a set too small to interpret it
The draft includes a funnel plot for an outcome contributed by fewer than ten studies. The respondent states that asymmetry cannot be assessed reliably at that number and that presenting the plot invites a conclusion the data cannot support.
The respondent proposes that the plot be removed and replaced with a statement that publication bias could not be assessed.
The secretariat accepts this submission. Presenting an uninterpretable graphic is not a neutral act.
The funnel plot is removed for every outcome contributed by fewer than ten studies, and replaced by a statement that small-study effects could not be assessed at that number, together with the count of registered trials identified without posted results.
A sortable table implies a comparison the underlying data do not support
The draft presents a sortable table whose columns are drawn from sources of differing quality. The respondent states that sorting on such a column produces an ordering that looks like a ranking and is not one.
The respondent proposes that sorting be disabled on any column whose values are not commensurable.
The secretariat notes this submission and records that the point is correct in principle.
No amendment arises here because every sortable table in the document set already carries a standing statement above it that the ordering is not a ranking and that the values in each column are commensurable only where the column header says so. The proposal to disable sorting was considered and not adopted, because a reader who cannot sort a table generally sorts it elsewhere and without the statement.
The document should state what a reader ought to do
The draft assesses evidence and stops. The respondent, a practising clinician, states that a reader arriving at the document with a decision to make is left to convert an assessment into an action without help, and proposes that each document close with a recommendation.
The respondent argues that other evidence bodies issue recommendations and that declining to do so transfers the difficult part of the work to the reader.
The secretariat does not accept this submission, and records that the point is a reasonable one rather than a misunderstanding.
The Institute assesses evidence and does not issue recommendations, because a recommendation embeds values and a resource context that the Institute does not hold and cannot state. That constitutional limit is published on the methodology page and is not varied by consultation. The submission remains published in full.
Quantitative claims are reproduced without the method that produced them
Several figures in the draft are quoted from sources that determined them by different methods. A figure obtained by one determination and a figure obtained by another are not comparable, and the draft places them in the same sentence without distinguishing them.
The respondent, an analytical chemist, proposes that every quantitative claim carry the method that produced it at the point of use rather than in the reference.
The secretariat accepts this submission. Placing two figures side by side is an implicit claim that they are the same kind of quantity, and in the cases identified they were not.
Every quantitative claim now carries the determination that produced it at the point of use, and figures obtained by non-comparable methods are no longer presented in the same row or sentence.
Statistical heterogeneity is treated as though it measured clinical heterogeneity
The draft reports a heterogeneity statistic and proceeds to pool where it is low. The respondent states that a low statistic in a small set of trials is uninformative, and that clinical and methodological similarity should be assessed before any statistic is consulted.
The respondent proposes that the decision to pool be justified on clinical grounds first and that the statistic be reported as a description rather than used as a threshold.
The secretariat accepts this submission in part. The decision to pool is now made on clinical and methodological grounds and stated as such. The statistic continues to be reported, because readers expect it and its absence would be read as concealment.
The decision to pool is now justified in prose against the population, intervention, comparator and outcome before any statistic is presented, and the heterogeneity statistic is reported with its confidence interval and a note of the number of contributing studies.
Analytical surveys are treated as evidence about suppliers when they establish only what was in a sample
Several included surveys purchased material anonymously and analysed it. The respondent states that where the chain from a named supplier to the analysed vial cannot be documented, the result describes a sample and not a supplier.
The respondent proposes that provenance be an explicit eligibility dimension, with surveys reported separately according to whether it could be established.
The secretariat accepts this submission. Moderate certainty evidence from the included surveys supports statements about material circulating in a market; it does not support statements about any named supplier's output.
Provenance is now assessed for every included survey and reported as a study characteristic, surveys without establishable provenance are reported separately rather than pooled with those that have it, and no supplier-level inference is drawn from a sample-level result.
Overlapping primary studies across included reviews are counted more than once
The draft is an overview of reviews and several included reviews share primary studies. The respondent states that the overview reports the total number of participants across reviews as though the sets were disjoint.
The respondent proposes that overlap be assessed and reported, and that no total be given without correcting for it.
The secretariat accepts this submission. An inflated participant total overstates the evidence base by an amount the reader cannot see.
Overlap between included reviews is now assessed at primary-study level and reported in a citation matrix, and participant totals are reported for the union of primary studies rather than as a sum across reviews.
Studies not published in English were excluded without assessment
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.
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.
Intention-to-treat and efficacy-estimand results are combined without distinction
Several contributing trials report both a treatment-policy result and an efficacy result that censors at discontinuation. The draft draws from whichever is reported first in each paper.
The respondent, a trial statistician, states that the two answer different questions, that the difference is substantial where discontinuation is common, and that a synthesis should choose one and say which.
The secretariat accepts this submission. Mixing estimands within a single pooled estimate is a defect of the synthesis rather than of the trials.
The treatment-policy estimand is used throughout as the primary analysis, the efficacy estimand is reported as a secondary analysis where available, and the estimand used is stated in every row of the summary of findings.
The document is unreadable without specialist training
The respondent, a trustee of a patient organisation, states that the draft is written for a reader who already understands certainty grading, and that the people most affected by the subject matter will not reach the assessment at all.
The respondent proposes a plain-language summary at the head of every document, written to the same standard of accuracy as the document itself and not as a promotional abstract.
The secretariat accepts this submission in part. A plain-language summary is added. The proposal that it replace the technical abstract is declined, because the abstract is the part of the document other assessors read and cite.
Every document now opens with a plain-language summary of not more than 150 words, placed above the technical abstract and carrying the same certainty language, so that the two cannot diverge.
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.
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
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