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. 2019 Jan 31;2019(1):CD012424. doi: 10.1002/14651858.CD012424.pub2

Merom 2016.

Methods Study design: Cluster‐RCT
Number of study arms: 2
Number of clusters: 23
Length of follow‐up: 12 months
Participants Setting: Sydney, Australia
Number of participants: 530
Number analysed: 522
Number lost to follow‐up: 8
Sample: living in retirement village
Age (years): Age > 80 years: 39%
Sex: 85% female
Inclusion criteria: Eligible participants had to be a resident of the village; be able to walk at least 50 m; agree to undergo physical and cognitive testing; plan to stay in the village for the next 12 months; and obtain medical clearance to participate in the study
Exclusion criteria: Participants were excluded if they planned to leave the village for 3 months or more during the trial period, or if they scored < 24 on the MMSE in the baseline assessment indicating cognitive impairment
Interventions 1. Group‐based social dancing: folk dancing or ballroom dancing classes with gradual increase in cognitive complexity and cardiovascular effort; 1 hour, 2 a week, for 12 months
2. Control group: usual activities, and asked not to join a dance class during the trial period, placed on a wait list for the dance classes at the end of trial.
Outcomes 1. Rate of falls
2. Number of people who experienced 1 or more falls (risk of falling)
3. Health‐related quality of life
4. Number of people who died
Duration of the study 52 weeks
Adherence Adherence measured by session attendance
1. Group‐based social dancing group: median session attendance was 56%, (IQR 26 – 77%) or approximately 45 sessions. The median attendance was lower for folk (55%) than ballroom dancing (60%)
Notes Source of funding: NHMRC
Economic information: not reported
Number of clusters allocated to intervention: 12; number of clusters allocated to control: 11; number of clusters analysed (intervention): 12; number of clusters analysed (control): 11
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Computer‐generated randomisation method, constrained using minimisation
Allocation concealment (selection bias) Unclear risk The relative timing of the randomisation of clusters and recruitment of participants is unclear. It is unclear whether personnel recruiting participants were blinded to intervention group to which the cluster was randomised
Blinding of participants and personnel (performance bias) 
 All outcomes Unclear risk Participants and personnel unblinded but impact of unblinding unknown
Blinding of outcome assessment (detection bias) 
 Falls Low risk Falls were recorded using the same method in each group
Quote: "The recording of falls from participant diaries was performed by research staff blind to allocation"
Blinding of outcome assessment (detection bias) 
 Fractures Unclear risk Not applicable
Blinding of outcome assessment (detection bias) 
 Hospital admission, medical attention and adverse events Unclear risk Not applicable
Blinding of outcome assessment (detection bias) 
 Health related quality of life (self report) High risk Participants were not blinded to group allocation
Incomplete outcome data (attrition bias) 
 Falls and fallers Low risk Less than 20% of fall data were missing (1%). There were missing fall data from an equal number of participants in the intervention group (n = 4) and the control group (n = 4). The reason for missing fall data was not clear
Selective reporting (reporting bias) Low risk Prespecified falls and adverse event outcomes reported. Prospective trial registration available and specifies the same fall outcomes as those in the trial report
Method of ascertaining falls (recall bias) Low risk Participants were asked to record “F” (fall) or “N” (no fall) each day using monthly calendars (diaries), which were returned by mail at the end of each month. Participants who reported a fall were interviewed by telephone to obtain details about where the fall(s) occurred; whether the fall resulted in injuries; and whether any treatment was sought. Participants who did not return their calendars within 2 weeks were telephoned by study researchers and verbal responses were recorded. At the end of the call, they were also requested to return their calendar by mail to maintain completeness
Cluster‐randomised trials Unclear risk The relative timing of the randomisation of clusters and recruitment of participants is unclear. There was attempt at concealment,
Quote: "Retirement villages were randomised by the trial statistician... The trial statistician advised the study coordinator of the village’s allocation, and the study coordinator arranged the delivery of the intervention. Allocation was thus concealed from the research team that were recruiting villages and participants and performing the baseline assessments"
Baseline comparison of the intervention arms is reported, but not baseline comparability of clusters;
Quote: "Retention to the 12‐month assessment varied markedly by village ranging from 60% to 92%"; accounted for the clustered design in the analysis; results comparable with individually‐randomised trials