Randomised controlled trial and economic evaluation of the ‘Families for Health’ programme to reduce obesity in children

Objective Evaluating effectiveness and cost-effectiveness of ‘Families for Health V2′ (FFH) compared with usual care (UC). Design Multicentre randomised controlled trial (RCT) (investigators blinded, families unblinded) and economic evaluation. Stratified randomisation by family; target of 120 families. Setting Three National Health Service Primary Care Trusts in West Midlands, England. Participants Overweight or obese (≥91st or ≥98th centile body mass index (BMI)) children aged 6–11 years and their parents/carers, recruited March 2012–February 2014. Interventions FFH; a 10-week community-based family programme addressing parenting, lifestyle change and social and emotional development. UC; usual support for childhood obesity at each site. Main outcome measures Primary outcomes were 12-months change in children's BMI z-score and incremental cost per quality-adjusted life-year gained (QALY). Secondary outcomes included changes in children's physical activity, fruit and vegetable consumption and quality of life, parents' BMI and mental well-being, family eating/activity, parent-child relationships and parenting style. Results 115 families (128 children) were randomised to FFH (n=56) or UC (n=59). There was no significant difference in BMI z-score 12-months change (0.114, 95% CI −0.001 to 0.229, p=0.053; p=0.026 in favour of UC with missing value multiple imputation). One secondary outcome, change in children's waist z-score, was significantly different between groups in favour of UC (0.15, 95% CI 0.00 to 0.29). Economic evaluation showed that mean costs were significantly higher for FFH than UC (£998 vs £548, p<0.001). Mean incremental cost-effectiveness of FFH was estimated at £552 175 per QALY. Conclusions FFH was neither effective nor cost-effective for the management of obesity compared with UC. Trial registration number ISRCTN45032201.

from self-reported work status information. Other family-borne costs were valued using data reported by the parents as part of the follow-up resource use questionnaires. Unit costs were inflated where necessary to 2013-14 prices (£ sterling) using the National Health Service Hospital and Community Health Services Pay and Prices Index. No discounting of costs or benefits was applied as the time horizon was less than 12 months.

Calculation of utilities and quality adjusted life years
The economic evaluation made use of quality-adjusted life-years (QALYs) to measure preference-based health outcomes. The health-related quality of life of the study children was assessed using the EuroQol EQ-5D-Y (EuroQol) (Eidt-Koch et al., 2009;Wille and Ravens-Sieberer, 2006) obtained from both parents and children at baseline, and 3 and 12 months after randomisation. The standard UK (York A1) tariff values (Dolan 1997) were applied to these responses at each time point to obtain health utility scores. Qualityadjusted life-years (QALYs) were calculated using linear interpolation between baseline and follow-up utility scores and form the main health outcome measure of the economic evaluation.

Analyses of resource use, costs and outcome data
Resource use items were summarised by trial allocation group and follow-up period and differences between groups were analysed using t-tests for continuous variables and χ 2 test for categorical variables. Mean (standard error (SE)) costs by cost category and mean (SE) total costs were estimated by trial allocation group for all time periods. Total costs were estimated from both an NHS and personal social services (PSS) perspective and from a broader societal perspective. Cost comparisons were carried out using Student t tests.
Differences in mean total costs and their respective CIs were estimated. Non-parametric bootstrap (NICE, 2013) estimates based on 1000 replications were also calculated for these differences in mean costs and their respective CIs calculated.

Cost-effectiveness analyses
The main cost-effectiveness analyses were conducted for complete cases (i.e. those with complete cost and outcome data). The cost-effectiveness results were expressed primarily in terms of an incremental cost-effectiveness ratio (ICER). This was calculated as the difference in mean costs divided by the difference in mean outcomes (QALYs or change in BMI-z score between baseline and 12-months) between the trial comparators. The primary analyses took the perspective of the NHS and Personal Social Services. The nonparametric bootstrapping approach was used to determine the level of sampling uncertainty surrounding the mean ICER by generating 10,000 estimates of incremental costs and benefits. These were represented graphically on four quadrant cost-effectiveness planes. Cost-effectiveness acceptability curves (CEACs) showing the probability that the 'Families for Health' programme was cost-effective relative to usual care across a range of cost-effectiveness thresholds were also generated based on the proportion of bootstrap replicates with positive incremental net benefits. Unless otherwise stated, all statements about cost effectiveness are based on a £20,000 per QALY gained threshold. The probability that 'Families for Health' is less costly or more effective than usual care was based on the proportion of bootstrap replicates that had negative incremental costs or positive incremental health benefits.
Secondary analyses were also conducted where the outcomes remained unchanged from the main cost-effectiveness analyses but for the costs a wider societal perspective was taken that included broader economic costs.

Sensitivity and sub-group analyses
Several sensitivity analyses were undertaken to assess the impact of areas of uncertainty surrounding components of the economic evaluation. These involved re-estimating the main cost-effectiveness outcomes under the following scenarios: 1) conducting a per protocol analysis where families having participated in 5 or more sessions of the 'Families for Health' programme are regarded as 'programme completers', i.e. as having complied with the protocol sufficiently; 2) multiple imputation of all missing cost and outcomes data; 3) parentreported EQ-5D-Y values for the study child(ren) substituted for child self-reported values in the formulation for QALYs; and 4) incorporation of EQ-5D values reflecting the main parent's self-reported health within calculations of overall QALYs gained.
Sub-group analyses were conducted for the main cost-effectiveness results to explore heterogeneity in the trial population. These were conducted by: (i) age group (6-8 years, 9-11 years); (ii) gender (boys, girls); and (iii) site (Site A, Site B, Site C).

Cost-effectiveness
When a study perspective of the NHS and personal social services was adopted (i.e. that adopted for the baseline analysis) and health outcomes were measured in terms of QALYs, the average total cost was £1,019 in the 'Families for Health' group, compared with £507 in the usual care group, generating a mean incremental cost of £512 (among those with complete cost and QALY data),. The mean incremental cost-effectiveness of the 'Families for Health' programme was estimated at £552,175 per QALY gained. The cost-effectiveness acceptability curve shown in Figure 3 of the main body of the paper indicates that regardless of the value of the cost-effectiveness threshold, the probability that the 'Families for Health' programme is cost-effective does not exceed 40%. If decision-makers are willing to pay £20,000 for an additional QALY, the probability that the 'Families for Health' programme is cost effective is approximately 28%. Broadening the study perspective to that of society as a whole had little effect on these cost-effectiveness results. In particular, the mean incremental cost-effectiveness ratio remained relatively static at £559,115 per QALY gained and the probability that the 'Families for Health' programme is cost effective at a £20,000 costeffectiveness threshold remained unchanged at 28%.
When a study perspective of the NHS and personal social services was adopted and health outcomes were measured in terms of longitudinal change in BMI z score, the average total cost was £998 in the 'Families for Health' group, compared with £548 in the usual care group, generating a mean incremental cost of £450 (among those with complete cost and BMI z score data). The mean incremental cost-effectiveness of the 'Families for Health' programme was estimated at -£3935 per unit change in BMI z score. Regardless of the value of the cost-effectiveness threshold, the probability that the 'Families for Health' programme is cost-effective did not exceed 2% (on the basis of the BMI z score). If decision-makers are willing to pay £20,000 per unit change in BMI z score, the probability that the 'Families for Health' programme is cost effective was less than 1%. Broadening the study perspective to that of society as a whole had little effect on these cost-effectiveness results. In particular, the mean incremental cost-effectiveness ratio remained relatively static at -£3,748 per unit change in BMI z score and the probability that the 'Families for Health' programme is cost effective at a £20,000 cost-effectiveness threshold remained unchanged at less than 1%.

Sensitivity analyses
Several sensitivity analyses were undertaken to assess the impact of uncertainty on the costeffectiveness results. A 'per protocol' analysis was performed that defined 'programme completers' as families that participated in 5 or more sessions of the 'Families for Health' programme and non-completers as families that participated in less than 5 sessions of the 'Families for Health' programme. These analyses were also restricted to the baseline NHS and personal social services perspective. Of particular note is that for programme completers, the mean incremental cost per QALY gained attributable to the 'Families for Health' programme declined to £27,790 and the probability that the programme is cost effective at a £20,000 cost-effectiveness threshold increased to 43%. This compared to a mean incremental cost per QALY gained for the programme of -£6,441 (indicating that usual care is dominant in health economic terms) and a probability that the programme is cost effective at a £20,000 cost-effectiveness threshold of 17% amongst non-completers.
We also re-estimated cost-effectiveness following multiple imputation of all missing cost and outcomes data, i.e. estimates were calculated for all 128 study children. Of particular note is that following multiple imputation, the mean incremental cost per QALY gained (assuming a NHS and personal social services perspective) attributable to the 'Families for Health' programme declined to £9119 and the probability that the programme is cost effective at a £20,000 cost-effectiveness threshold increased to 67%. Similar results were observed when a societal perspective for costs was adopted. In contrast, when the BMI z score was considered as the health outcome measure, the 'Families for Health' programme remained dominated by usual care in health economic terms and the probability that the programme is cost-effective did not exceed 6% regardless of the value of the cost-effectiveness threshold.
We also re-estimated cost-effectiveness when alternative sources and inputs for EQ-5D utility values were incorporated into the analyses. Using parent-reported EQ-5D-Y values for the study child(ren) to substitute for child self-reported values in the formulation for QALYs removed the incremental QALY benefit associated with the 'Families for Health' programme. The probability that the programme is cost effective at a £20,000 costeffectiveness threshold declined to 23% when a NHS and personal social services perspective was adopted and 25% when a societal perspective was adopted. Furthermore, the reduction in incremental QALYs associated with the 'Families for Health' programme increased when EQ-5D values reflecting the main parent's self-reported health were also incorporated within calculations of overall QALYs gained. The probability that the programme is cost effective at a £20,000 cost-effectiveness threshold declined to 2%.

Sub-group analyses
Several sub-group analysis were conducted to explore the heterogeneity in our costeffectiveness results. The sub-groups considered in our analyses were: (i) age group (6-8 years, 9-11 years); (ii) gender (boys, girls); and (iii) site (Site A, Site B, Site C). The costeffectiveness results for two particular sub-groups of children are worthy of comment. First, when the QALY measure was considered as the primary health outcome measure, the probability of cost-effectiveness of the 'Families for Health' programme was notably higher for girls than for boys: 67% versus 15% at a £20,000 cost-effectiveness threshold from a NHS and personal social services perspective and 63% versus 16% at a £20,000 costeffectiveness threshold from a societal perspective. Second, when the QALY measure was considered as the primary health outcome measure, the probability of cost-effectiveness of the 'Families for Health' programme was notably higher in Site A than in Site B or Site C: 61% versus 11% versus 36% at a £20,000 cost-effectiveness threshold from a NHS and personal social services perspective and 64% versus 7% versus 35% at a £20,000 costeffectiveness threshold from a societal perspective. These patterns were not replicated for the BMI z-score outcome measure.