Time until nursing home admission (NHA) in different types of dementia is not known. Few studies in Alzheimer's disease (AD) have been reported previously and focused on demographic, socioeconomic, behavioral and psychiatric symptoms as predictors for NHA.

We use data from the Norwegian DEMVEST-cohort to calculate time until NHA applying Kaplan-Meier survival analysis comparing the Lewy body dementias (LBD) (Dementia with Lewy Bodies (DLB) and Parkinson's Disease Dementia (PDD)) to non-LBD patients. Associated factors were studied with a Cox proportional hazard model.

190 cases with the same degree of mild dementia at baseline were followed for on average 880 ± 397 days 95% CI (823, 937), 56 (29.5%) individuals were placed in a nursing home during follow up and mean time until institutionalization was 1204 days 95% CI(1130, 1279) for all included, 987 days 95% CI (823, 1151) for LBD patients and 1263 days 95% CI (1184, 1342) for non-LBD patients. p=0.007 (Log-Rank test) Chi-square= 7.330 df=1. Mean time until NHA for DLB patients is 985days 95%CI (801, 1169) and for AD patients 1264days 95% CI (1180, 1347) p=0.013 (Log-Rank test) Chi square=6.194 df=1

After controlling for age and duration at baseline we find that having a LBD diagnosis (DLB or PDD) increases the risk for nursing home placement during follow-up, hazard ratio =1.9 95%CI (1.1, 3.4) p= 0.030.

We find that a LBD diagnosis significantly shortens time until NHP controlling for age and duration at baseline compared to non-LBD patients.