Our study findings relating to the trial of peer educators to increase the uptake of mobile radiographic screening have previously been published.74 Parts of this section have been reproduced or adapted from Aldridge et al.74 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0. The text includes minor additions and formatting changes to the original text.
Introduction
Tuberculosis rates in London are among the highest in Europe, and account for nearly 40% of UK cases.75,76 Rates are highest in so-called ‘hard-to-reach’ groups (people experiencing homelessness, prisoners and drug users),3 many of whom have infectious tuberculosis, delays to diagnosis, poor adherence to treatment and high levels of loss to follow-up before treatment completion.3 Congregate living and reluctance to engage with services complicate attempts to identify active and latent tuberculosis in these populations.77
The pan-London Find&Treat tuberculosis service includes a mobile digital radiographic unit and has been shown to be cost-effective among hard-to-reach groups (people experiencing homelessness, substance misusers and prisoners).10 Mobile radiographic unit screening can detect tuberculosis early, often before people become infectious.26,78 Historical data (Dr Alistair Story, Find&Treat, 2019, personal communication) show low uptake rates in eligible individuals resident in homeless hostels (around 50%).
Increased screening uptake has the potential to increase cost-effectiveness, reduce the transmission of tuberculosis and improve the health of this vulnerable population. Peer educators (with lived experience of homelessness, problem drug or alcohol use and tuberculosis) may be able to engage more effectively with those experiencing these issues than health service staff. Peer educators have been shown to improve knowledge about health conditions and increase the use of health services in several areas including HIV, smoking and condom use.79,80 Previous qualitative research has found that volunteer peers working alongside tuberculosis services derive value from their involvement with the service and the opportunities this provides for meaningful, structured activity.81
Using a CRCT, we aimed to compare current practice in central London (where Find&Treat and hostel staff encourage people experiencing homelessness to be screened for tuberculosis) with the use of peer educators who have direct experience of tuberculosis and homelessness.
Methods
Setting
The setting was London hostels for people experiencing homelessness targeted for mobile radiographic screening by Find&Treat between February 2012 and October 2013.
Inclusion criteria
All homeless hostels in London taking part in mobile radiographic unit screening for active pulmonary tuberculosis run by Find&Treat were eligible for inclusion in the study if they had taken part in two previous screening sessions and had not been screened in the 6 months prior to the scheduled mobile radiographic unit screening session.
Exclusion criteria
People experiencing homelessness screened at projects such as day centres and drug and alcohol recovery projects, and street populations accessing soup kitchens (where the denominator population is unknown) were excluded. Hostels with a previous uptake of > 80% were excluded as it was felt that peers would be unlikely to further improve screening uptake.
Usual practice
Find&Treat staff were present on the mobile radiographic unit to encourage uptake and manage onward referrals for suspected cases of active tuberculosis (usual practice for Find&Treat).
Intervention
Peer educators were recruited via tuberculosis clinics in London or from the Find&Treat service where staff identified, or were approached by, interested service users. Training was provided through a 3-day training session run by Groundswell, the research team and Find&Treat. Training covered tuberculosis transmission, tuberculosis risk groups, tuberculosis treatment, the importance of screening, how to maximise screening uptake (based on the past experiences of Find&Treat staff) and the additional support available for those undergoing screening. Peer educators also underwent a period of shadowing an existing peer educator to learn how to increase screening uptake. Ongoing support for peers was provided by Groundswell, a registered charity that exists to enable homeless and vulnerable people to take more control of their lives, have a greater influence on services and play a fuller role in the community.82
On the day of screening, peers introduced themselves to the hostel staff and agreed a work plan. Peers then moved around the hostel according to the agreed plan of work, knocked on residents’ doors (in conjunction with hostel staff), spoke to residents in all communal areas and those available close to the hostel location (next to the mobile radiographic unit) to encourage them to take up the offer of screening. Mobile radiographic unit staff were available in the mobile radiographic unit to encourage uptake as per usual practice.
Additional interventions
Hostel managers were invited to a meeting hosted by Find&Treat to explain the purpose of the study and obtain their agreement and consent for participation in the study. Hostel managers who were unable to attend the meeting were contacted by e-mail and telephoned when necessary. Hostel managers were reassured that the study was evaluating a peer intervention and not individual hostel performance.
Primary outcome
The primary outcome was the proportion of those resident at the hostel who were screened for active tuberculosis in the mobile radiographic unit. The number of residents eligible for screening at each hostel was determined from bed lists at each site, which took account of the number of residents actually staying at a venue overnight and excluded persons who were absent on the day of screening as a result of hospital admission, arrest or their whereabouts being unknown. Outcome data were collected at an aggregate (hostel) level, with no collection of individual-level data.
Power
The intracluster correlation coefficient for this study was estimated at 0.08 based on previous service data. This produced an inflation factor of 6.52, assuming an average hostel size of 70 residents. Subsequent to funding and prior to trial initiation, a decrease in average hostel size across London reduced the average size to around 50 residents. Consequently, the inflation factor was recalculated as 4.84. To detect a 15% difference in screening uptake in the two groups (60% vs. 75%) in an individually randomised controlled trial with 90% power at the 5% significance level would require 216 individuals in each arm. Applying the 4.84-fold inflation factor for the clustered randomised design required at least 1045 individuals, or approximately 21 hostels in each arm.
Randomisation
The unit of randomisation was hostel screening venue. A cluster randomised design was chosen because the intervention was aimed at the hostel sites rather than at individual clients. Randomisation was carried out by the study research team using a master list of hostels. Sites were randomised to the intervention group or the control group using the internet-based service Sealed Envelope™ (Sealed Envelope Ltd, London, UK), which ensured allocation concealment until the interventions were assigned. To ensure comparability between the intervention arm and the control arm, hostels were stratified on the basis of their size (binary variable indicating whether or not hostels had > 43 beds – the median size) and previous screening uptake level (binary variable indicating whether or not hostels had > 50% historical uptake).
Blinding
Blinding of participants and observers was not possible. The study statistician (RWA) conducted analysis blind to the allocation of intervention arm or control arm.
Poisson regression analysis was used to analyse outcome events at screening hostels with robust standard errors to account for clustering at the hostel level. Bed occupancy level was included as the exposure variable, screening uptake as the outcome (or indicator) variable, and hostel venue as a random effect to account for clustering at each site. The analysis was adjusted by inclusion of the randomisation stratification factors of historical uptake rates and bed numbers.
Data were analysed in Stata version 12.
The study had ethics approval from East of England – Essex National Research Ethics Service (committee number 10/H0302/5). The study trial registration number is ISRCTN17270334.
Results
There were 59 hostels considered; 12 were excluded because of uptake rates of > 80% and one was excluded because it would not allow peers into the venue. Forty-six hostels with a total of 2342 residents were randomised, 1192 in control hostels and 1150 in intervention hostels (Figure 4). Randomisation appeared well balanced (chi-squared p-value > 0.47 for all baseline characteristics; Table 7).
FIGURE 4 Work package 3 flow diagram. ITT, intention to treat. Reproduced from Aldridge et al.74 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0/. The figure includes minor additions and formatting changes to the original text. (Figure not reproduced here; see the original article.)
| Hostel characteristic | Control | Intervention | ||
|---|---|---|---|---|
| n | % | n | % | |
| London tuberculosis sectora | ||||
| North Central | 7 | 29 | 4 | 18 |
| North East | 6 | 25 | 7 | 32 |
| North West | 5 | 21 | 8 | 36 |
| South East | 6 | 25 | 3 | 14 |
| Hostel size | ||||
| ≤ 43 beds | 13 | 54 | 12 | 55 |
| > 43 beds | 11 | 46 | 10 | 45 |
| Historical screening uptake | ||||
| ≤ 50% | 15 | 63 | 12 | 55 |
| > 50% | 9 | 38 | 10 | 45 |
| Incentives provided for screeningb | ||||
| No | 15 | 63 | 15 | 68 |
| Yes | 9 | 38 | 6 | 27 |
| Unknown | 0 | 0 | 1 | 5 |
Median screening uptake was 44% [interquartile range (IQR) 26–59%)]: 45% (IQR 33–55%) in control hostels and 40% (IQR 25–61%) in intervention hostels. Using Poisson regression to account for the clustered study design, size of hostel and previous screening uptake, there was no evidence of peer educators affecting the uptake of screening, with an adjusted risk ratio of 0.98 (95% CI 0.80 to 1.20) (Table 8). These results did not differ significantly in secondary analyses examining the effect by hostel size, historical screening uptake and intervention fidelity (Table 9).
| Variable | Control (n) | Intervention (n) | Total | Unadjusteda,b intervention group risk ratio (95% CI) | Adjusteda,c intervention group risk ratio (95% CI) |
|---|---|---|---|---|---|
| Number of individuals eligible for screening | 1192 | 1150 | 2342 | – | – |
| Number of individuals eligible for screening per hostela | 35 (27–71) | 36 (27–52) | 35 (27–70) | – | – |
| Number of individuals screened | 503 | 468 | 29 (13–38) | 0.96 (0.76 to 1.23) | 0.98 (0.79 to 1.21) |
| Hostel engagement and characteristics | Control: eligible (number screened) | Intervention: eligible (number screened) | Total | Unadjusted intervention group risk ratio (95% CI) | Adjusteda intervention group risk ratio (95% CI) |
|---|---|---|---|---|---|
| Per protocol – peers attended intervention hostel on day of screening | 1192 (503) | 1051 (432) | 2243 (935) | 0.97 (0.75 to 1.26) | 0.97 (0.78 to 1.22) |
| Hostel did not participate effectivelyb | 748 (267) | 444 (137) | 1192 (404) | 0.86 (0.67 to 1.11) | 0.88 (0.67 to 1.14) |
| Hostel size | |||||
| ≤ 43 beds | 362 (176) | 338 (134) | 700 (310) | 0.82 (0.60 to 1.11) | 0.80 (0.60 to 1.06) |
| > 43 beds | 830 (327) | 812 (334) | 1642 (661) | 1.04 (0.76 to 1.43) | 1.08 (0.82 to 1.42) |
| Historical screening uptake | |||||
| ≤ 50% | 694 (272) | 718 (241) | 1412 (513) | 0.86 (0.64 to 1.14) | 0.86 (0.65 to 1.14) |
| > 50% | 498 (231) | 432 (227) | 930 (458) | 1.13 (0.85 to 1.51) | 1.13 (0.85 to 1.51) |
The study team noted no adverse events.
Discussion
This CRCT showed no evidence that peer educators increased the uptake of screening.
The study included most homeless hostels being screened by Find&Treat, a project with broad geographical coverage across London. Cluster randomisation was used as individual randomisation would not have been possible. The study was not powered to detect a difference in tuberculosis cases identified by the two arms as this would require a considerably larger sample. We did not collect individual data as part of the study as this would have required individual consent and would have interrupted the flow of screening and caused unacceptable delays for service users.
Evidence of the effectiveness of peer education interventions is mixed. One review found evidence for peer education increasing physical activity, decreasing smoking and increasing condom use, but no evidence for breastfeeding, medication adherence, women’s health and participation in general activities.79 A further review of the use of peers educators in HIV also found mixed evidence of effects.80 This same review attempted to examine what implementation factors, including peer educator recruitment, supervision and training, improved effectiveness, but found a lack of evidence to support any of these approaches, partly as a result of low sample size.
Several factors may have influenced results. Most sites were not naive to the peer intervention as a result of the increased use of peers alongside Find&Treat in the time between the study design and its conduct; thus, at several sites we, in effect, withdrew the ‘intervention’ from the control arm. The prior use of peers may have led to an increased awareness among hostel staff and residents, reducing any effect during the trial. The primary outcome of screening uptake does not take account of peers’ previously reported ability81 to engage the more difficult-to-reach and vulnerable cases, which could be assessed only by the collection of individual-level data. Such an effect (if it exists) could ultimately lead to an increase in the rate of detection of active tuberculosis. Having peers available at the time of screening may also help with the engagement of those who are screened and require further health-care management. Peers are then able to accompany people to follow-up appointments, based on a relationship that began on the mobile radiographic unit during the peer education work. Finally, the presence of peers may have reduced the intensiveness with which Find&Treat staff promoted uptake but may have freed them to focus on other activities. Peers in this study were associated with minimal costs as they were volunteers and may benefit from involvement in structured, meaningful activity as suggested by previous qualitative studies.81
We found no evidence for an increased uptake of screening in this study; however, peer educators may have contributed to other, unmeasured factors in the screening process. Additionally, involvement of peers in the screening is likely to have directly benefited the peers as a result of the training and skills that were learnt during the research process, factors that were not measured during this study.
Acknowledgements
We would like to acknowledge the invaluable help and support of Groundswell and all the peers who volunteered for this trial.
Deviations from the protocol
With the exception of the revised power calculations that were required because of the change in average hostel size and the exclusion of one hostel as a result of the refusal of the hostel to allow peer workers on site, there were no recorded protocol violations.
Added value
Find&Treat and Groundswell continue to highly value the role of peers; however, partly as a result of this study, Find&Treat has evolved the peer model, increasingly moving volunteer peers into paid roles providing support across the diagnostic and treatment pathway. There is an emphasis on matching peers to clients’ backgrounds to support their care. There is also an emphasis on training peers to undertake clinical activities, such as obtaining oral swabs, conducting near-patient tests for blood-borne viruses and undertaking liver fibroscanning. Partly as a result of our involvement in this study, we are now collaborating on a NIHR Research for Patient Benefit grant assessing the effectiveness of the Groundswell peer advocacy model (Chief Investigator Lucy Platt). A Wellcome Trust Clinical Research Fellow (Neha Pathak) is also using Groundswell peer educators in a survey of cervical cancer screening uptake and sexually transmitted infection prevalence among women experiencing homelessness.