Table 1.
Summary of methodological issues
| Methodological issue | Findings | Evidence | Strategies for improvement |
| 1. Did the feasibility study allow a sample size calculation for the main trial? | Response rate less than expected but absolute numbers potentially allow for sample size calculation for main trial once a suitable design has been determined. | See figure 3. 66/324 (20%) eligible infants were recruited. 56/66 infants had an IROC assessment, but data from three assessments were missing due to data transfer errors, resulting in 53 complete assessments. 40% of infants assessed for overweight risk were above population risk. |
Allow for longer recruitment time. Allow for more recruitment sites. |
| 2. What factors influenced eligibility and what proportion of those approached were eligible? | Fewer infants attending for 6–8 weeks check in the study areas. High number of screened infants were reported not to have met the inclusion/exclusion criteria (see figure 3). |
HV managers at the NHS Trusts estimated there would be 700 infants born into the study areas within a 3-month period. NHS Child Health Records showed 589 estimated potential participants in the study period, of which 324 (45%) were identified by HVs. It is not known how many of the infants who were unrecorded by the HVs might have been eligible for the study. HVs recorded screening 324 (55%) parents. Of these, 226 (70%) were recorded as eligible for the study. | In the UK, it is not possible to employ dedicated researchers in one organisation to directly recruit participants to studies being undertaken in another organisation. Therefore. participant identification has to be undertaken via a gatekeeper employed by the organisation where the research is taking place. However, once participants are identified dedicated researchers can recruit directly (as was undertaken in this study). Investment in additional training in participant identification is required for HVs. This would require investment from the HVs employing Trusts in terms of time for training activities and continuing professional development. Researcher to screen all participants for eligibility. Direct patient recruitment but this may not enable engagement of the most deprived families with whom HVs have regular contact. |
| 3. Was recruitment successful? | Recruitment target not met despite extending the recruitment period extended from 3 to 5 months. Challenges at individual and team level. |
66 parents recruited in 5.5 and 7 months. Not all HVs who were trained took part in the study (22/28). Some did not recruit parents to the study. |
Funding for translation and interpreting services. Preproject discussions about the impact of professional gatekeeping with HVs. Further research is needed to identify barriers and enablers to research recruitment by HVs so that evidence-based interventions to improve recruitment can be developed. |
| 4. Did eligible participants consent? | Low conversion to consent. | 226 infants were eligible. 88 (38%) parents refused to participate. 138 parents were identified as being interested in the study. A failure of communication between researchers and some HVs meant that 16 parents who had given their permission to be contacted were not followed-up. Researchers were unable to get responses to their telephone calls from 22% (30/138) of parents who initially expressed interest in the study. 66 (48%) consented to participate. |
Improve communication pathways between HVs and research team. Research team more visible in child health clinics to ensure they are recognisable to parents. |
| 5. Were participants successfully randomised and did randomisation yield equality in groups? | Not assessed | ||
| 6. Were blinding procedures adequate? | Not assessed | ||
| 7. Did participants adhere to the intervention? | Not all parents had a ProAsk assessment/viewed the therapeutic wheel. | 56/66 infants received the risk assessment. Interviews with HVs revealed that all 10 parents who did not receive an assessment were not at home when they called. 21/53 were found to be at above population risk but only five of these received the therapeutic wheel intervention per protocol. Process evaluation revealed that n=4 parents received the assessment but did not receive the risk score feedback. |
Better engagement with HVs around the project aims and objectives, and provision of HV time for ongoing engagement with and support from research team about intervention delivery. Audit of study processes by research staff and feedback to HVs to increase adherence to the intervention. Increase accessibility to research team for participants with concerns/questions. |
| 8. Was the intervention acceptable to the participants? | Some parents and HVs did not take part in the study. Low number of parents consenting suggest some were concerned about the intervention |
6/28 HVs declined to take part in the study. Qualitative interviews suggests they were wary of raising issue of infant weight but adjusted their practice to incorporate ProAsk. 88 (38%) parents refused to take part following initial interest. Parent participants found the intervention acceptable. |
Determine in further qualitative analysis the particular issues or components of the intervention that HVs were uncomfortable with. |
| 9. Was it possible to calculate intervention costs and duration? | Not assessed | ||
| 10. Were outcome assessments completed | HVs were able to complete risk score on 56 participants. Follow-up questionnaire completion rate low. The number of returned questionnaires was much higher for parents of infants found to be at above population risk. |
See table 2 for more details of outcome data. 34/66 parents completed follow-up questionnaire, of which 29 were usable. 15 (71%) of parents whose infants were at higher risk returned their follow-up questionnaire. Of those at population risk, 19 (42%) returned the follow-up questionnaire. |
Audit and feedback by research staff to HVs to increase outcome assessments. Recontact parents for reminders to complete outcome questionnaires. |
| 11. Were outcomes measured those that were the most appropriate outcomes? | The proposed primary outcome measure primary outcome measure of weight-for-age z-score. Missing anthropometric data mainly in relation to infant length and head circumference at both baseline and follow-up. Low numbers of parents recorded the date of the anthropometric measures on the questionnaires. Of those that did there was a date discrepancy between completion of the self-report aspect of the questionnaires (by parent at home) and the associated anthropometric measures (collected in clinic). The proposed secondary outcomes were parenting self-efficacy, maternal feeding style, infant diet and exposure to physical activity/sedentary behaviour. |
Number of infant anthropometric measures completed Baseline (total n=66) Weight n=64, length n=26, head circumference n=34. Follow-up (total n=34) Weight n=28, length n=15, head circumference n=14. The anthropometric measures on the baseline questionnaire that were dated (n=13) were recorded on average 22 days earlier than the parent report data. The anthropometric measures on the follow-up questionnaire that were dated (n=8) were recorded on average 15 days earlier. All follow-up questionnaires that were returned were completed. Cronbach’s alpha for the measures was >0.5 |
Train research team in infant anthropometric measurement and include resources for a follow-up visit by researchers to obviate the need for self-report of infant anthropometrics at baseline and follow-up. Ensure anthropometric measurement timing fits with HV service schedule. |
| 12. Was retention to study good? | Retention was low. | 34/66 (52%) of parents completed follow-up questionnaire. The average time to complete was 28 weeks (min 23, max 39 weeks). Because the intervention was not delivered per protocol, there was a time lapse between the assessment and follow-up. 12 parents agreed to post-study qualitative interviews. |
Strategies to maintain participant engagement in study are needed for a larger trial. For example, updates via website, newsletter or text messaging. |
| 13. Were the logistics of running a multicentre trial assessed? | One centre recruited better than the others. This team work well together and there were low levels of staff change and conflict. | Site 1 recruited n=39/109 eligible infants (36%), site 2 n=15/83 (18%), site 3 n=3/10 (30%), site 4 n=9/38 (24%). |
Training to include team working around peer support, conflict, etc |
| 14. Did all components of the intervention work together? | There were some difficulties blending the ProAsk risk assessment and the motivational approach. The motivational interviewing training was too early and insufficient for some HVs. |
ProAsk delivered in its entirety to most parents. Only five HVs completed the goal setting stage resulting in a failure to offer follow-up care to parents of infants identified as at above average risk of overweight. Mismatch between MI training and implementation timing. |
Communication training for HVs in raising risk and motivational approaches bespoke to childhood overweight prevention. |
HV, health visitor; ProAsk, Proactive Assessment of Obesity Risk during Infancy.