Effectiveness of treatments for people living with severe dementia: A systematic review and meta-analysis of randomised controlled clinical trials.

BACKGROUND: Dementia is a progressive neurodegenerative syndrome that has no cure. Although a significant proportion of people with dementia progress into the severe stages of the disease, evidence on the clinical effectiveness of treatments for people with severe dementia remains limited. AIMS: To systematically review the effectiveness of pharmacological and non-pharmacological treatments for people living with severe dementia and assess the quality of the evidence. METHOD: We searched MEDLINE, EMBASE, PsycINFO, CINAHL and online clinical trial registers up to January 2022, for Randomised Controlled Trials (RCT) in people living with severe dementia. Quality and risk of bias were assessed independently by two authors. RESULTS: A total of 30 trials met our inclusion criteria of which 14 evaluated the effectiveness of pharmacological treatments, and 16 evaluated a non-pharmacological intervention. Pharmacological treatments: Meta-analyses indicated that pharmacological treatments (donepezil: 10 mg, 5 mg; galantamine: 24 mg; memantine: 10 mg) are associated with better outcomes compared to placebo for: severity of symptoms (standardized mean difference (SMD) 0.37, 95% CI 0.26-0.48; 4 studies; moderate-certainty evidence), activities of daily living (SMD 0.15, 95% CI 0.04-0.26; 5 studies; moderate-certainty evidence), and clinical impression of change (Relative Risk (RR) 1.34, 95% CI 1.14-1.57; 4 studies; low-certainty evidence). Pharmacological treatments were also more likely to reduce mortality compared to placebo (RR 0.60, 95% CI 0.40-0.89; 6 studies; low-certainty evidence). Non-pharmacological treatments: Five trials were included in the meta-analyses of non-pharmacological interventions (multi-sensory stimulation, needs assessment, and activities-based interventions); results showed that non-pharmacological interventions may reduce neuropsychiatric symptoms of dementia compared to usual care (SMD -0.33, 95% CI -0.59 to -0.06; low certainty evidence). CONCLUSIONS: There is moderate-certainty evidence that pharmacological treatments may decrease disease severity and improve function for people with severe dementia. Non-pharmacological treatments are probably effective in reducing neuropsychiatric symptoms but the quality of evidence remains low. There is an urgent need for high-quality evidence for other outcomes and for developing service-user informed interventions for this under-served group.