Background
Proposed reporting items for CRXO trials
Section | CONSORT Item no. | CONSORT 2012 extension for cluster trial design for Item no. | Reporting quality assessment measure | Reported? (N = 83) |
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Title and Abstract | ||||
Identification of design in title | 1a | Identification as a cluster randomised trial in the title | Identification as a CRXO trial in the title | 7 (8%) |
Reporting in abstract | 1b | Identification as a CRXO trial in the abstract | 21 (25%) | |
Background and objectives | ||||
Rationale for design | 2a | Rationale for using a cluster design | Rationale for using a cluster design AND a crossover of interventions at the cluster level | 20 (24%) |
Hypothesis and objectives | 2b | Whether objectives pertain to the cluster level, the individual participant level or both | No modification proposed | Not assessed |
Trial design | ||||
Description of trial design | 3a | Definition of cluster and description of how the design features apply to the clusters | Schematic representation of design (recommended especially for designs with >2 periods or interventions) | 23 (28%) |
Definition of the cluster | 77 (93%) | |||
Clear differentiation between cluster-period and cluster. | Not assessed | |||
Number of clusters | 79 (95%) | |||
Number of periods | 76 (92%) | |||
Duration of each time period or when the cross over will occur | Not assessed | |||
Cohort, repeated cross-sectional, or mixture of designs participants in each period | 83 (100%) | |||
Discussion of the potential for carryover to occur | 17 (20%) | |||
Reporting of use of washout period | 83 (100%) | |||
Participants | ||||
Eligibility criteria | 4a | Eligibility criteria for clusters | No modification proposed | Not assessed |
Interventions | ||||
Description of interventions | 5 | Whether interventions pertain to the cluster level, the individual participant level or both | No modification proposed | Not assessed |
Outcomes | ||||
Description of outcome measures | 6a | Whether outcome measures pertain to the cluster level, the individual participant level or both | No modification proposed | Not assessed |
Sample size | 7a | Method of calculation, number of clusters(s) (and whether equal or unequal cluster sizes are assumed), cluster size, a coefficient of intracluster correlation (ICC or k), and an indication of its uncertainty | Was the method for sample size calculation reported, or justification for no sample size calculation provided? | 48 (58%) |
Reference to the method used for the sample size calculation | Not assessed | |||
Justification for number of clusters | 33 (40%) | |||
Justification for number of periods | 9 (11%) | |||
Equal or unequal number of periods per cluster | Not assessed | |||
Equal or unequal cluster-period sizes | 42 (51%) | |||
A value for the within-cluster within-period ICC or variance components or other measure of correlations within data or justification for not including | 13 (16%) | |||
A value for the within-cluster between-period ICC or variance components or other measure of correlations within data or justification for not including | 4 (5%) | |||
A reference or explanation for the choice of ICCs or other measure of correlations | 5 (6%) | |||
Reported whether the sample size methodology accounted for repeated measurements on the same individual | Not assessed | |||
Sequence generation | ||||
Method used to generate allocation sequence | 8a | Method used to generate the random allocation sequence | No modification proposed | 36 (43%) |
Type of randomisation | 8b | Details of stratification or matching if used | Does the article report whether stratified randomisation used? | 83 (100%) |
Allocation concealment mechanism | ||||
Method used to implement the allocation sequence | 9 | Specification that allocation was based on clusters rather than individuals and whether allocation concealment (if any) was at the cluster level, the individual participant level, or both | Does the article report whether the people allocating the intervention sequence to the clusters know the allocation sequence? | 40 (48%) |
Does the article report whether people recruiting/identifying participants knew which intervention sequence has been assigned to the cluster? (n = 57)a | 44 (77%) | |||
Does the article report whether the people recruiting/identifying participants could have influenced which people were recruited/identified for inclusion in the study? (n = 57)a | 54 (95%) | |||
Implementation | ||||
Method used to include clusters in trial | 10a | Who generated the random allocation sequence, who enrolled clusters, and who assigned clusters to interventions | No modification proposed | Not assessed |
Method used to include individuals in clusters | 10b | Mechanism by which individual participants were included in clusters for the purposes of the trial (such as complete enumeration, random sampling) | No modification proposed | Not assessed |
Method of obtaining consent | 10c | From whom consent was sought (representatives of the cluster, or individual cluster members, or both), and whether consent was sought before or after randomisation | From whom was consent sought? | 60 (72%) |
Was consent sought before or after randomisation of the cluster when consent was sought from individuals? (n = 30) | 16 (53%) | |||
Blinding | 11a | If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how. | Were the participants aware of the intervention assigned to the cluster? | 67 (81%) |
Were the researchers who delivered the intervention, i.e. caregiver, aware of the intervention assigned to the cluster? | 82 (99%) | |||
If the outcome was self-reported (n = 14), was the participant aware of the intervention assigned to the cluster? | 13 (93%) | |||
If the outcome was assessed by another person (n = 69), was the outcome assessor aware of the intervention assigned to the cluster? | 45 (65%) | |||
Statistical methods | 12a | How clustering was taken into account | Justification for statistical analysis methods | Not assessed |
Reported whether the analysis was performed at the cluster or individual level. | 78 (94%) | |||
Where there are more than two periods, reported whether a single correlation is assumed for the within-cluster between-period correlation | 0 (0%) | |||
Was it possible to determine the method for accounting for both the cluster randomisation and multiple period aspects? | 64 (77%) | |||
Was it possible to determine the method for accounting for the cluster randomisation aspect? | 70 (84%) | |||
Was it possible to determine the method for accounting for the multiple period design aspect? | 70 (84%) | |||
Results | ||||
Participant flow | ||||
Number of clusters and participants | 13a | For each group, the numbers of clusters that were randomly assigned, received intended treatment, and were analysed for the primary outcome | For each group, reported the number of clusters that were randomly assigned, received intended treatment in each period, and were analysed for the primary outcome | Not assessed |
For each group, reported the number of individuals that were randomly assigned, received the intended intervention in each period, and were analysed for the primary outcome | Not assessed | |||
Losses and exclusions | 13b | For each group, losses and exclusions for both clusters and individual cluster members | For each group, losses and exclusions for clusters, cluster-periods, and individual participants | Not assessed |
Baseline data | 15 | Baseline characteristics for the individual and cluster levels as applicable for each group | Presentation of baseline characteristics data in table | |
No baseline characteristics table in article | 24 (29%) | |||
Reported by total only | 8 (10%) | |||
Reported by randomisation sequence with or without total | 7 (8%) | |||
Reported by cluster only | 2 (2%) | |||
Reported by intervention with or without total | 37 (45%) | |||
Reported by cluster and period | 2 (2%) | |||
Reported by intervention and period | 1 (1%) | |||
Reported by intervention, period, and cluster | 2 (2%) | |||
Number analysed | 16 | For each group, number of clusters included in each analysis | For each group, number of clusters, cluster-periods, and participants included in each analysis, stating reasons for exclusions | Not assessed |
Outcomes and estimation | 17a | Results at the individual or cluster level as applicable and a \coefficient of intracluster correlation (ICC or k) for each primary outcome | A coefficient for the within-cluster within-period correlation and within-cluster between-period correlation, or other measure (such as variance components), for each primary outcome | 0 (0%) |
Generalisability | 21 | Generalisability to clusters and/or individual participants (as relevant) | No modification proposed | Not assessed |
Title and abstract (Items 1a, b)
Background and objectives (Item 2a)
Trial design (Item 3a)
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Report the total number of randomised clusters in the trial.
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Report the total number of planned time periods for each cluster in the trial.
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Report the duration of each time period, for example, the duration of time or number of participants included in each cluster-period before the intervention is crossed over.
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Report whether the same, different, or a mix of same and different participants were included in each cluster-period. These designs are described as cohort, repeated cross-sectional, or mixture designs, respectively.
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For complex designs (i.e. designs with more than two interventions and two periods), consider including a schematic representation of the trial design depicting which interventions were allocated to each cluster in each period. For a simple design, the participant flow diagram (Item 13) may suffice.
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Report the potential of the effect of the intervention given in one cluster-period to carry over to subsequent cluster-periods.
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Report methods for managing the risk of carryover, if necessary.
Sample size (Item 7a)
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Provide a reference for the sample size methodology or a description of the method when the method is not published.
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Report how the sample size methodology accounts for both the cluster randomisation (e.g. the within-cluster within-period ICC) and the multiple period aspects of the design (e.g. the within-cluster between-period ICC).
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Report how the sample size methodology accounts for whether the same, different, or a mix of the same and different participants will be included in each cluster-period.
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Report the number of clusters, number of periods, and number of participants per cluster-period, noting which are assumed and which are determined by the sample size calculation.
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Report whether a variable or constant number of periods per cluster and participants per cluster-period is assumed.
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Report the parameter values used to account for cluster randomisation and multiple periods.
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Provide a justification for the choice of parameter values and state any constraints on the number of clusters, number of periods, or number of participants per cluster-period.
Statistical methods (Item 12a)
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Provide a reference for the statistical methodology or a description of the method when the method is not published.
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Report whether the analysis was performed at the individual or cluster level.
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Report how both the cluster randomisation and the multiple period aspects of the design were accounted for.
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When there were more than two periods, report whether a constant within-cluster between-period ICC was assumed, and, if a constant within-cluster between-period ICC is not assumed, report what assumption or methodology was used.
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Describe how missing data will be managed at both the individual level and the cluster level [16].
Participant flow (Items 13a, b)
Baseline data (Item 15)
Characteristic | Intervention sequence AB | Intervention sequence BA | ||
---|---|---|---|---|
Period 1–Intervention A Group 1 | Period 2–Intervention B Group 2 | Period 1–Intervention B Group 3 | Period 2–Intervention A Group 4 | |
Time-invariant characteristics | ||||
Time-invariant cluster characteristic | Such as proportion of each ward type: Cardiac: 25% Intensive Care: 40% Neurology: 35% | Such as proportion of each ward type: Cardiac: 25% Intensive Care: 40% Neurology: 35% | Such as proportion of each ward type: Cardiac: 35% Intensive Care: 45% Neurology: 20% | Such as proportion of each ward type: Cardiac: 35% Intensive Care: 45% Neurology: 20% |
Time-invariant participant characteristic (cohort design only) | Such as patient sex: 59% male | Such as patient sex: 59% male | Such as patient sex: 48% male | Such as patient sex: 48% male |
Time-varying characteristics | ||||
Time-varying cluster characteristic | Nurse-to-patient ratio over 24 h, Median (IQR): 2.1 (2.0 – 2.2) | Nurse-to-patient ratio over 24 h, Median (IQR): 2.0 (1.9 – 2.1) | Nurse-to-patient ratio over 24 h, Median (IQR): 2.3 (2.1 – 2.4) | Nurse-to-patient ratio over 24 h, Median (IQR): 2.2 (2.1 – 2.4) |
Time-varying participant characteristic (cohort and repeated cross-sectional design) | Such as patient weight (kg), Mean (SD): 83.4 (14.2) | Such as patient weight (kg), Mean (SD): 78.9 (15.6) | Such as patient weight (kg), Mean (SD): 81.2 (13.2) | Such as patient weight (kg), Mean (SD): 80.4 (11.2) |
Time-invariant characteristics
Time-varying characteristics
Number analysed (Item 16)
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Present the number of clusters, cluster-periods, and participants analysed for the primary outcome as per the participant flow diagram (Fig. 1).
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Report the number of clusters that contribute to the analysis across all periods, also separately by intervention sequence, and give reasons for the exclusion of any whole clusters.
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Report the number of clusters that contribute to the analysis for only some periods, also separately by intervention and intervention sequence. Give reasons for the exclusion of any cluster-periods and state whether the remaining clusters-periods from that cluster were included.
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Report the number of participants included in the analysis, by intervention and intervention sequence, including the reasons for any exclusions at the individual level.
Outcomes and estimation (Item 17a)
Methods
Literature search
Trial inclusion criteria
Selection of trials for inclusion in the review
Data extraction and management
Data coding
Data analysis
Results
Results of the search
Characteristics of the trials
Disease or domain under study | n (%) (N = 83) |
---|---|
Infection control | 19 (23%) |
Cardiovascular disease | 10 (12%) |
Health services delivery | 9 (11%) |
Infectious disease | 8 (10%) |
General and public health | 5 (6%) |
Medical training | 5 (6%) |
Communication of health information | 4 (5%) |
Pregnancy, childbirth, and early childhood | 3 (4%) |
Mental health and behavioural conditions | 3 (4%) |
Respiratory disease | 3 (4%) |
Blood sample contamination | 3 (4%) |
Cognition | 3 (4%) |
Central nervous system and musculoskeletal disease | 2 (2%) |
Oral health | 2 (2%) |
Nutritional and metabolic disorders | 1 (1%) |
Urogenital disease | 1 (1%) |
Digestive disorders | 1 (1%) |
Pain management | 1 (1%) |
Type of intervention | |
Intervention targeting the individual | 42 (51%) |
Intervention targeting health care provider | 21 (25%) |
Quality improvement intervention | 14 (17%) |
Intervention resulting in change to the participant environment | 6 (7%) |
Number of interventions | |
2 | 74 (89%) |
3 | 8 (10%) |
4 | 1 (1%) |
Number of clusters - Median [IQR]; Range | 2 – 268 |
Unclear | 4 (5%) |
Number of periodsa | |
2 | 53 (70%) |
3 | 8 (11%) |
4+ | 15 (18%) |
Unclear | 7 (8%) |
Cluster-period size - Median [IQR]; Range | 27 [14–77]; 2 – 1319 |
Unclear | 17 (20%) |
Quality of reporting in CRXO trials as assessed against proposed or modified reporting items and other indicators
Quality of reporting in CRXO trials to allow assessment of bias
Selection bias
Bias | Sufficient information to evaluate risk of bias (N = 83) |
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Selection bias | 25 (30%) |
Performance bias | 67 (81%) |
Detection bias | 58 (70%) |