Survival in Frontotemporal Lobar Degeneration in a Korean Population

Frontotemporal lobar degeneration (FTLD) can be subdivided into frontotemporal dementia (FTD), FTD combined with motor neuron disease (FTD-MND), semantic dementia (SD), and progressive nonfluent aphasia (PNFA). FTLD has been considered a rare disorder, and its' demographic and survival data have rarely been studied in Asian population. A survival analysis using the Kaplan-Meier method was performed for 121 consecutive patients with clinically diagnosed FTLD who attended the Memory Disorder Clinic at Samsung Medical Center in Seoul, Republic of Korea, between January 1995 and September 2006. The overall median survival from the onset of the first symptom was 9.6 years (95% CI = 8.3-10.8 y). The survival was shortest in FTD-MND (3 y) and longest in SD (11.3 y). The median survival time of FTD (9.8 y) was shorter than that of SD and longer than that of FTD-MND and PNFA. The use of the Cox proportional-hazards model to examine the effect of demographics on survival revealed that only age at onset was associated with survival. In general, our data are comparable with those from the Western countries. However, the female proportion was greater across all subtypes of FTLD and the survival of patients with PNFA was shorter than those of other groups.