Heard 2017.

Study characteristics
Methods	Study design: cost‐effectiveness analysis. Data drawn from the Chaboyer 2014 RCT Analytical approach: trial‐based evaluation Effectiveness data: data from pilot RCT (N = 87) (Chaboyer 2014). Key effectiveness inputs were SSI and quality of life (SF‐12) at up to 4 weeks post‐discharge in trial. Perspective: Australian public health care provider Utility valuations: QALYs were calculated from SF‐12 data. QoL indices (utility weights) were calculated using the method of Brazier and Roberts. QALYs were estimated from the utility weights using the standard area under the curve method. Adjustment: QALYs were adjusted for differences in baseline SF‐12 indices using the regression‐based adjustment of Manca, Hawkins and Sculpher. Measure of benefit: surgical site infection avoided; QALY Cost data: measured in AUSD; in hospital resource use data were collected by direct observation or chart audit during the trial. Included cost of intervention, nursing time for dressing changes, hospital (inpatient) care. No discount rate was applied due to the short time horizon. Analysis of uncertainty: a nonparametric bootstrap with 1000 replications was used to construct 95% percentile method confidence intervals (CIs) for the estimates. A sensitivity analysis used only post‐discharge QALYs, ignoring the period of hospitalisation (the base case analysis calculating QALYs from utility weights assumed that the change in QoL over the hospital stay was linear). Funding: Office of Health and Medical Research, Queensland Health, the National Health and Medical Research Council Centre of Research Excellence in Nursing and a Gold Coast University Hospital Private Practice grant.
Participants	Location: Obstetric unit, Australia Intervention group: n = 46,control group: n = 46 (obese women (> 30 BMI) undergoing elective CS) Mean age: intervention group = 30.6 years (SD 5.5),control group = 30.7 years (SD 5.0) Inclusion criteria: booked for elective CS; pre‐pregnancy BMI > 30; able to provide consent. Exclusion criteria: women whose condition changed to require urgent CS; previous participation in the trial; existing infection.
Interventions	Aim/s: to evaluate whether NPWT is cost‐effective compared with standard care in preventing surgical site infection among obese women undergoing caesarean section.   Group 1 (NPWT) intervention: NPWT: PICO (Smith and Nephew) dressing applied over the primarily closed incision by the surgeon in the operating room. Dressing was left on for 4 days, or longer if drainage continued, unless soiled or dislodged (n = 44) in Heard 2017 trial). Group 2 (Comparator) intervention: Comfeel dressing applied over the primarily closed incision by the surgeon in the operating room. Dressing was left on for 4 days, or longer if drainage continued, unless soiled or dislodged (n = 43 in a trial). Study date/s: July 2012 to April 2014
Outcomes	For data see Heard 2017 and for clinical data see Chaboyer 2014 in additional table 1 Surgical site infection Costs (AUSD) QALY (measure of benefit). ICER with 95% CI (AUSD per unit outcome) to inform probability of intervention being cost‐effective
Notes	Authors' conclusions: NPWT may be cost‐effective in the prophylactic treatment of surgical wounds following elective caesarean section in obese women. Larger trials could clarify the cost‐effectiveness of NPWT as a prophylactic treatment for SSI. Sensitive capture of QALYs and cost offsets will be important given the high level of uncertainty around the point estimate cost‐effectiveness ratio which was close to conventional thresholds. Quality rating according to the CHEERS checklist was 83.3%.