AbstractBackgroundUrinary tract infections (UTIs) are common causes of avoidable emergency hospitalisation in people living with dementia (PLWD). PLWD are at higher risk of UTIs, which can often cause death. Previous research in older adults has suggested that survival following infection is reduced by delays in antibiotic treatment (Gharbi et al., 2019). Here we investigate the incidence of UTIs in people with and without dementia and test whether delays in antibiotic treatment particularly increase mortality in PLWD.MethodData were extracted for 2.47 million people aged 50 and living in Wales from 2000‐2021 using the SAIL Databank (Figure 1). UTI incidence was calculated as the number of cases identified in GP and hospital records using diagnostic codes. Temporal clustering was applied to remove redundant coding occurring within 90 days. Eligible PLWD and paired non‐dementia (ND) groups were selected monthly using propensity sampling, matching for age, sex, and socioeconomic deprivation. Cox regression was used to study the effects of immediate and deferred treatment (1‐7 days after diagnosis) on survival, focusing on the last recorded UTI in a subset of patients diagnosed and treated at the primary care level.ResultUTI incidence was higher in PLWD compared to ND (11.21.85 vs 4.30.75, 1:1000) over 22 years (Figure 2). We also observed an increase in UTIs leading to death within 60 days of the infection (1.560.4 vs 0.60.2, 1:1000). We performed Cox regression survival analysis on 76,283 last UTIs with 2,973 observed events (deaths). Age, sex, dementia, and treatment timing were used as predictors. Mortality risk was significantly increased in PLWD relative to ND (***HR = 2.06,[1.91,2.23],z = 18.2) (Figure 3). Mortality was also increased in older adults (***HR = 1.07,[1.07,1.08],z = 36.4) and in males (***HR = 1.50,[1.40,1.61],z = 11.3). Furthermore, deferred treatment was associated with increased mortality (***HR = 1.58,[1.43,1.74],z = 8.93), replicating previous findings. The interaction between dementia and treatment timing was not significant.ConclusionOur study found increased UTI incidence and mortality rates in PLWD. Deferred treatment was associated with higher mortality, regardless of dementia diagnosis. Early intervention and frequent screening may reduce adverse health outcomes. Further research is needed to determine the best strategies to prevent and manage UTIs in PLWD.