Preliminary model assessing the cost-effectiveness of preoperative chlorhexidine mouthwash at reducing postoperative pneumonia among abdominal surgery patients in South Africa

Research output: Contribution to journalArticlepeer-review


  • NIHR Global Health Research Unit on Global Surgery
  • ASOS Investigators
  • STARSurg Collaborative


Background: Pneumonia is a common and severe complication of abdominal surgery, and is associated with increased length of hospital stay, healthcare costs, and mortality. Rates of pulmonary complications have risen further during the SARS-CoV-2 pandemic. This study aimed to explore the potential cost-effectiveness of administering preoperative chlorhexidine mouthwash versus no-mouthwash in reducing postoperative pneumonia among abdominal surgery patients.

Methods: A decision analytic model taking the South African healthcare provider perspective. We compared the costs and benefits of mouthwash versus no-mouthwash-surgery with a 30-day time horizon. We assumed two scenarios in South Africa: (i) the absence of COVID-19; (ii) the presence of COVID-19. Input parameters were collected from prospective cohort studies, published literature and expert opinion. Effectiveness was measured as proportion of pneumonia patients. Deterministic and probabilistic sensitivity analyses were performed to assess the impact of parameter uncertainties. The results of the probabilistic sensitivity analysis were presented using cost-effectiveness planes and cost-effectiveness acceptability curves.

Results: In the absence of COVID-19, mouthwash had lower average costs compared to no-mouthwash-surgery, $3,675 (R 63,770) versus $3,958 (R 68,683), and lower proportion of pneumonia patients, 0.029 versus 0.042 (dominance of mouthwash intervention). In the presence of COVID-19, the increase in pneumonia rate due to COVID-19, made mouthwash even more dominant as it was more beneficial to reduce pneumonia patients by using mouthwash. The cost-effectiveness acceptability curves shown that mouthwash surgery is likely to be cost-effective between $0 (R0) and $15,000 (R 260,220) willingness to pay thresholds.

Conclusions: Mouthwash is likely to be cost saving in reducing pneumonia after abdominal surgery versus no-mouthwash-surgery in both the absence and presence of SARS-CoV-2. The available evidence for the effectiveness of mouthwash was extrapolated from cardiac surgery; there is now an urgent need for a robust clinical trial on the intervention on non-cardiac surgery.


Original languageEnglish
Article numbere0254698
Number of pages19
JournalPLOS One
Issue number8
Publication statusPublished - 12 Aug 2021