Stark 2003.

Study characteristics
Methods	Parallel RCT. Comparing calorie intake and weight gain in 2 group interventions. Hypothesised that those receiving a behavioral intervention would eat more calories and gain more weight.
Participants	Population of interest, N = 10. 3 dropped out. Total sample, n = 7. Children aged 4 to 12 years with CF and their parents. Children had chronic pulmonary disease, pancreatic insufficiency and weight below the 40th percentile. Mild disease, chronic phase.
Interventions	Group educational & behavioural interventions: 1. nutritional education (n = 4); 2. behavioural intervention (n = 3). 7 sessions: baseline, 5 sessions (90 min each) plus 1 follow up session.
Outcomes	1. Calorie intake. 2. Weight. 3. Quality of parent/child interaction at mealtime. 4. CF coping skills. 5. Adherence to CF regimen. Assessments at baseline, post‐treatment and 6, 12 & 24 months follow up.
Notes	POI: daily calorie intake. Unclear what the population of interest was and how sample was selected. Attrition ‐ 3 dropped out. One spoke only Spanish. 1 had 3 children with CF, 1 of whom was hospitalised. 1 had conflicting time commitments. Equivalence at baseline unclear but unlikely.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The authors described that families were assigned based on family availability to time slots, which were in a second step then randomly assigned to one of the conditions 'via a coin flip' (Stark 2003, p. 244).
Allocation concealment (selection bias)	Low risk	See above.
Blinding (performance bias and detection bias) All outcomes	High risk	Participants and personnel providing the intervention were not able to be blinded due to the nature of the intervention. One primary outcome 'daily calorie intake' is assessed via self‐reported daily diet dairies. Due to that the measure is not objective and might be influenced by the knowledge of allocation to one of the conditions. The other objective measure used as primary outcome ('weight') is not likely to be influenced by the lack of blinding.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The authors described in detail the attrition and the reasons for families who dropped out, but it is relatively unclear what the population of interest was and how many families were randomly assigned. Out of originally 15 families, who agreed to participate, seven families completed treatment and follow up (Stark 2003, p. 240).
Selective reporting (reporting bias)	Low risk	All prespecified outcome variables (primary and secondary) are reported.