ABSTRACT Objective This systematic review and meta‐analysis evaluated the relationship between multimorbidity and polypharmacy on the oral health in older adults (aged 75 years or older). The PECO focus question set for this study was, ‘What is the occurrence, association and impact of multimorbidity and polypharmacy on the oral conditions and its management in older adults?’. Methods Electronic searches of MEDLINE (PubMed), Embase, and the Cochrane Library were conducted using the PECO (Population Exposure Comparison Outcome) framework. About 3433 studies published until April of 2025 were screened. Risk of bias was assessed using the Newcastle–Ottawa Scale. All eligible studies were descriptively analysed; studies that provided sufficient information were meta‐analysed. Results Twenty‐three studies 21 cross‐sectional and 2 cohort studies were included. Polypharmacy showed a significant association with dry mouth, as demonstrated by the pooled analysis (OR = 2.05; 95% CI: 1.31–3.22), along with consistent findings linking a higher number of medications to dry mouth and hyposalivation. Poor oral health assessment tool (OHAT) scores were also consistently associated with polypharmacy. In contrast, findings regarding multimorbidity/comorbidity were not consistently associated with dry mouth or with poor OHAT scores. Both exposures showed inconsistent associations with number of teeth, edentulism, and oral function. Quality assessment indicated that the included studies were predominantly at low risk of bias. Conclusions Polypharmacy may impact on dry mouth and hyposalivation in older adults, potentially independent of multimorbidity. However, the impact of multimorbidity and polypharmacy on other oral conditions remains unclear. Further high‐quality evidence, particularly from longitudinal studies, is needed to clarify these relationships and establish causal associations. Trial Registration PROSPERO Registration: CRD420251003698
Srisanoi et al. (Sun,) studied this question.