Survival time and differences between dementia with Lewy bodies and Alzheimer's disease following diagnosis: A meta-analysis of longitudinal studies.

OBJECTIVE: To synthesize the evidence across longitudinal studies comparing survival in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD).

METHODS: We conducted a systematic review and meta-analysis of studies comparing survival in clinically diagnosed DLB to AD. Longitudinal cohort studies were identified through a systematic search of major electronic databases from inception to May 2018. A random effects meta-analysis was performed to calculate survival time and relative risk of death.

RESULTS: Overall, 11 studies were identified including 22,952 patients with dementia: 2029 with DLB (mean diagnosis age 76.3; 47% female) compared with 20,923 with AD (mean diagnosis age 77.2; 65.1% female). Average survival time in DLB from diagnosis was 4.11 years (SD ± 4.10) and in AD 5.66 (SD ± 5.32) years, equating to a 1.60 (95% CI: -2.44 to -0.77) years shorter survival in DLB (p < 0.01). Relative risk of death was increased by 1.35 (95%CI: 1.17-1.55) in DLB compared to AD (p < 0.01). Differences in survival were not explained by follow-up time, age at diagnosis, gender, or cognitive score.

CONCLUSIONS: There is consistent evidence for higher and earlier mortality in DLB compared to AD. This is important for all stakeholders and underlines the importance of expanding research into DLB.