Guidance

3 Clinical evidence

3 Clinical evidence

Summary of clinical evidence

3.1 The evidence for Thopaz+ assessed by the external assessment centre (EAC) comprises 13 studies (n=1,632), including 9 comparative studies. Six of the studies were randomised controlled trials (n=826), although no blinding was possible because the devices used look very different. There was 1 non-comparative study in children (Costa et al. 2016) and the remaining studies were in adults. Only 1 study centre in 1 multicentre trial (Pompili et al. 2014) was in the UK: the 12 other studies were done in Europe, Asia and North America. For full details of the clinical evidence, see section 3 of the assessment report.

Main points from the EAC's analysis of the clinical evidence

3.2 The EAC considered that of the 6 randomised controlled trials:

  • Pompili et al. (2014) was well designed and reported, and of excellent quality

  • 4 were of good quality with clear protocols and results (Gilbert et al. 2015, Lijkendijk et al. 2015, Jablonski et al. 2013 and Marjanski et al. 2013)

  • Mier et al. (2010) was of lower quality with no clear hypothesis but had well-matched comparative groups of patients.

    The EAC also noted that 3 observational comparative studies (Pompili et al. 2011, Miller et al. 2016 and Shoji et al. 2016) were of high quality using propensity-matched control cohorts.

3.3 The EAC considered that all of the sites in the studies were likely to have different local protocols for inserting and removing chest drains, which may make the results more reflective of the likely variation in chest tube drainage protocols across the NHS.

3.4 All but 1 of the comparative studies (Jablonski et al. 2013) were on the use of Thopaz+ after pulmonary resection. All of the comparators were conventional analogue drainage units using wall suction. The results showed that Thopaz+ was associated with shorter drainage times (7 of 8 studies) and a shorter length of stay (4 of 6 studies) compared with conventional chest drainage.

3.5 Two studies that included patients with pneumothorax (air in the pleural space around the lung) were identified, 1 of which was comparative (n=60; Jablonski et al. 2013). Results from the comparative study showed that both drainage time and length of hospital stay are statistically significantly shorter with Thopaz+.

3.6 Chest drains needed to be reinserted in 4 of the comparative trials. Rates of reinsertion were lower for Thopaz+ than for conventional chest drainage, but the difference was not statistically significant.

3.7 The EAC found no published quantitative, comparative evidence for staff time spent on chest drainage when using Thopaz+ or for fluid loss measurement.

Summary of economic evidence

3.8 The company's economic submission was a simple decision tree with 1 decision node for the use of Thopaz+ or conventional chest drainage with wall suction, based on inputs from Pompili et al. (2011). The time horizon was the length of hospital stay. For full details of the economic evidence, see section 3 of the assessment report.

EAC's analysis of the economic evidence

3.9 The EAC agreed that the company's simple model structure was appropriate, but it made some changes to better reflect the evidence and current NHS practice. These changes comprised:

  • adding costs for consumables and training associated with standard drainage

  • using a length of hospital stay of 5.4 days for Thopaz+ (based on a weighted average from 6 studies) and 5.8 days for conventional chest drainage (based on 3 studies)

  • using a drainage time of 3.5 days for Thopaz+ (based on 8 studies)

  • adding the cost of chest drain reinsertion and complications (reinsertion prevalence was calculated as 0.017 from 4 studies)

  • revising the consumer and training costs for Thopaz+.

    For full details of these changes, see section 4.4 of the assessment report.

3.10 The company's base case resulted in a cost saving per patient of £35.56 for Thopaz+ compared with conventional chest drainage over the length of hospital stay. After the EAC's changes, this cost saving increased to £107.99 per patient [2022].

3.11 The main driver of the cost savings for Thopaz+ is shorter length of hospital stay. The device remained cost saving throughout all realistic one-way sensitivity analyses.