Does oral hygiene prevents nosocomial infections in hospitalized patients? A systematic review and meta-analysis

Background: This study aimed to evaluate the impact of oral hygiene (OH) with chlorhexidine (CHX) on the evolution of nosocomial infections (NI). Material and Methods: Electronic searches were carried out in PubMed, Scopus, Cochrane Library, Web of Science, VHL, and Grey Literature databases. Randomized clinical trials were included. Methodological quality and risk of bias were assessed using RoB 2.0. Meta-analyses were carried out comparing patients who did or did not receive OH with CHX (0.05%, 0.12% and 2%) for NI, Ventilator-Associated Pneumonia (VAP), S. aureus infection (SA), duration of mechanical ventilation (MV), length of hospital stay and Intensive Care Unit (ICU). The certainty of evidence (CE) was evaluated with GRADE approach. Results: Thirteen studies were selected for quantitative and qualitative synthesis. The risk for VAP (RR 0.72 [0.58, 0.90], p=0.003) and NI (RR 0.70 [0.58, 0.83], p<0.001) were lower in patients of the CHX groups compared to controls, independently for [CHX] used for NI (RR >= 0.49, p <= 0.03). Patients who received CHX 2x/day presented similar risk to control (RR 0.98 [0.75, 1.30], p=0.91); while 3 and 4x/day or more (RR >= 0.52, p <= 0.002) presented lower risk for NI. Similar risk for SA was observed among groups (RR 0.42 [0.14, 1.26], p=0.12). The average days of hospitalization (p=0.67), ICU stay (p=0.37) and MV (p=0.57) did not differ between the groups. CE ranged from very low to moderate. Conclusions: OH with CHX reduced NI, regardless of concentration, when used 3x/day or more. However, it had no effect against AS and did not reduce length of hospital stay.