Prevalence of persistent vegetative state in patients with severe traumatic brain injury and its trend during the past four decades: A meta-analysis.

BACKGROUND Estimating the prevalence of persistent vegetative state (PVS) following severe traumatic brain injury (sTBI) and its change over time is important for the study of the disease. OBJECTIVE To estimate the prevalence of PVS at six months after sTBI and its trend over the past four decades, and to explore the effect of demographic data, such as age and sex, on the prevalence of PVS. METHOD Observational studies presenting the prevalence of PVS or the number of patients with PVS at six months after sTBI were included in the analysis. The overall prevalence and prevalence within pre-defined time intervals were calculated and meta-regression analysis was performed to assess the effect of age, gender, and time on the prevalence. RESULTS Twenty articles reporting 21 cohort studies were included. The overall prevalence of PVS at six months after injury was 2.77% (95% CI 0.0204-0.0375). There was no statistically significant trend towards time (P = 0.77). And we found no differences in prevalence according to age (P = 0.68) and gender (P = 0.57). CONCLUSIONS Prevalence of PVS at six months after sTBI has no significant change over the past four decades. Age and gender do not seem to have a significant effect on the prevalence.