Oral care measures for preventing nursing home-acquired pneumonia

Pneumonia in residents of nursing homes can be termed nursing home-acquired pneumonia (NHAP). NHAP is one of the most common infections identified in nursing home residents and has the highest mortality of any infection in this population. NHAP is associated with poor oral hygiene and may be caused by aspiration of oropharyngeal flora into the lung. Oral care measures to remove or disrupt oral plaque might reduce the risk of NHAP. This is the first update of a review published in 2018.

To assess effects of oral care measures for preventing nursing home-acquired pneumonia in residents of nursing homes and other long-term care facilities.

An information specialist searched CENTRAL, MEDLINE, Embase, one other database and three trials registers up to 12 May 2022. We also used additional search methods to identify published, unpublished and ongoing studies.

We included randomised controlled trials (RCTs) that evaluated the effects of oral care measures (brushing, swabbing, denture cleaning mouthrinse, or combination) in residents of any age in nursing homes and other long-term care facilities.

At least two review authors independently assessed search results, extracted data, and assessed risk of bias in the included studies. We contacted study authors for additional information. We pooled data from studies with similar interventions and outcomes. We reported risk ratios (RRs) for dichotomous outcomes, mean differences (MDs) for continuous outcomes, and hazard ratios (HRs) or incidence rate ratio (IRR) for time-to-event outcomes, using random-effects models.

We included six RCTs (6244 participants), all of which were at high risk of bias. Three studies were carried out in Japan, two in the USA, and one in France. The studies evaluated one comparison: professional oral care versus usual oral care. We did not include the results from one study (834 participants) because it had been stopped at interim analysis.  Consistent results from five studies, with 5018 participants, provided insufficient evidence of a difference between professional oral care and usual (simple, self-administered) oral care in the incidence of pneumonia. Three studies reported HRs, one reported IRRs, and one reported RRs. Due to the variation in study design and follow-up duration, we decided not to pool the data. We downgraded the certainty of the evidence for this outcome by two levels to low: one level for study limitations (high risk of performance bias), and one level for imprecision. There was low-certainty evidence from meta-analysis of two individually randomised studies that professional oral care may reduce the risk of pneumonia-associated mortality compared with usual oral care at 24 months' follow-up (RR 0.43, 95% CI 0.25 to 0.76, 454 participants). Another study (2513 participants) reported insufficient evidence of a difference for this outcome at 18 months' follow-up. Three studies measured all-cause mortality and identified insufficient evidence of a difference between professional and usual oral care at 12 to 30 months' follow-up. Only one study (834 participants) measured the adverse effects of the interventions. The study identified no serious events and 64 non-serious events, the most common of which were oral cavity disturbances (not defined) and dental staining. No studies evaluated oral care versus no oral care.

Although low-certainty evidence suggests that professional oral care may reduce mortality compared to usual care when measured at 24 months, the effect of professional oral care on preventing NHAP remains largely unclear. Low-certainty evidence was inconclusive about the effects of this intervention on incidence and number of first episodes of NHAP. Due to differences in study design, effect measures, follow-up duration, and composition of the interventions, we cannot determine the optimal oral care protocol from current evidence.  Future trials will require larger samples, robust methods that ensure low risk of bias, and more practicable interventions for nursing home residents.