Table 1 Quality of reporting of cluster randomised crossover trials as assessed against items from a modified 2012 CONSORT statement extension for cluster randomised trials and selected items from the 2010 CONSORT statement
Section | CONSORT Item no. | CONSORT 2012 extension for cluster trial design for Item no. | Reporting quality assessment measure | Reported? (N = 83) |
|---|---|---|---|---|
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 |