| Study |
Bias |
| Randomisation process |
Deviations from intended interventions |
Missing outcome data |
Measurement of the outcome |
Selection of the reported results |
Overall |
| Authors' judgement |
Support for judgement |
Authors' judgement |
Support for judgement |
Authors' judgement |
Support for judgement |
Authors' judgement |
Support for judgement |
Authors' judgement |
Support for judgement |
Authors' judgement |
Support for judgement |
| Chalmers 2020 |
Low risk of bias |
Quote: "The randomisation schedule was created by the CTU using computer‐generated pseudo‐random code with permuted blocks of randomly varying size. The sequence was known only to the programmer until database lock." Baseline variables by treatment group do not suggest a problem with randomisation, characteristics well balanced (IPD available) |
Low risk of bias |
Not possible to blind participants’ carers, but there is no evidence that deviations arised because of the trial context. The control group rates of skin care application were consistent with other trials and observational studies (e.g. up to 75 % in Rendell et al. 2011). Quote: “Of families in the emollient group with complete questionnaire data on adherence at each time point, 466 (88%) of 532 had satisfactory adherence at 3 months, 427 (82%) of 519 at 6 months, and 375 (74%) of 506 at 12 months.” “No emollient was supplied to the control group, but self‐directed use of emollients at least three times per week to most of the body (contamination) occurred in 18% (82 of 457) at 3 months, 17% (62 of 372) at 6 months, and 15% (49 of 324) at 12 months.” |
Low risk of bias |
Sensitivity analysis using the IPD data shows conclusions do not change if all missing are assumed to not have allergic sensitisation to any foods, RR=1.34, 95% 0.92 to 1.96, or if all missing are assumed to have allergic sensitisation to foods, RR=1.08, 95% CI 0.94 to 1.24. |
Low risk of bias |
Quote: "Research nurses doing skin examinations, skin prick testing, food challenges, or making food allergy decisions, and the statistician, were masked to treatment allocation during the study." |
Low risk of bias |
Full trial dataset provided by investigators and IPD meta‐analysis SAP followed. |
Low risk of bias |
Low risk of bias in all domains. |
| Lowe 2018a |
Low risk of bias |
Quote from trial protocol: "A computer generated random allocation list in blocks of variable length (4‐12) will be used. This list will be held by The RCH Pharmacy Department, which will be independent from the participant recruitment or testing. At all times, the allocation list will be concealed from the study coordinator and the other study investigators, who will manage participant recruitment." Baseline variables by treatment group do not suggest a problem with randomisation, characteristics well balanced (IPD available). |
Low risk of bias |
Not possible to blind participants’ carers, but there is no evidence that deviations arised because of the trial context. The control group rates of skin care application were consistent with other trials and observational studies e.g. up to 75 % in Rendell et al. 2011. The IPD shows regular use of emollient (≥ 3 days a week) by 11/36 (31%) control participants and 30/38 (79%) with eczema outcome recorded). |
Some concerns |
Outcome available for 70/80=88% of randomised participants at 12 months. Sensitivity analysis using the IPD reveals conclusions do not change significantly if everyone missing is assumed to not have allergic sensitisation to any food inhalant, 0.40 [0.11 to 1.38] but conclusions change if all missing the outcome are assumed to have allergic sensitisation, 0.89 [0.42 to 1.90] (point estimate of RR >20% of the complete case estimate). Missingness could have depended on outcome, but not likely. |
Low risk of bias |
Skin prick tests used by blinded assessor. |
Low risk of bias |
Full trial dataset provided by investigators and IPD meta‐analysis SAP followed. |
Some concerns |
Some concerns due to missing data (12% and results varied in sensitivity analysis) but low risk of bias in all other domains. |
| Skjerven 2020 |
Low risk of bias |
Quote: “we used computer‐generated cluster randomisation based on 92 geographical living area blocks as well as eight 3‐month time blocks. All infants born in the same 3‐month period and belonging to the same postal code or city area were allocated to the same intervention group”. Baseline variables by treatment group do not suggest a problem with randomisation, characteristics well balanced (IPD available). |
Low risk of bias |
Number of participants that were compliant in each arm for allergic sensitisation at 36months ‐ the IPD shows regular use of emollient (ceridal cream) (≥ 3 days a week averaged over intervention period) by 0 control participant and 211/343 = 62% intervention arm. |
Some concerns |
Outcome available for 63.4%. Sensitivity analysis using IPD reveals conclusions do not change significantly if everyone missing is assumed to not have allergic sensitisation to food, RR=0.87, [0.48, 1.59]. Conclusions change if all missing are assumed to have allergic sensitisation to food, RR=1.20 [1.04, 1.39] (point estimate of RR >20% of the complete case estimate). |
Low risk of bias |
Quote: "The study design did not allow for masking of study participants to the interventions. To limit the risk of observer bias, study personnel who did the clinical follow‐up investigations did not have access to the randomisation lists. Furthermore, parents were firmly instructed not to apply any type of emollient bath additives or leave‐on emollients within 24 h before each follow‐up investigation and all clinical assessments and investigations were done and recorded without knowledge of the group allocation." |
Low risk of bias |
Full trial dataset provided and IPD meta‐analysis SAP followed |
Some concerns |
Some concerns due to potential bias due to missing outcome data. All other domains classed as low risk of bias.
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