Life expectancy and median survival time in the permanent vegetative state.

The authors studied life expectancy and risk factors for mortality of persons in the vegetative state (VS). The study participants were 1,021 California patients in the VS during 1981-1996. Because of the large sample size, the authors were able to use multivariate methods to assess the effect of several risk factors on mortality. The authors found a strong secular trend in infant mortality, with rates in the mid-1990s being only one third of those in the early 1980s (P < 0.01). A smaller secular trend was observed for children aged 2-10 years and none for older patients. The mortality risk for older patients fell by approximately 8% for each year since the onset of the VS. The need for gastrostomy feeding was associated with a substantially higher risk, especially for infants and older patients (P < 0.01). Ventilator dependence also appeared to be a risk factor. On the basis of recent mortality rates, life expectancy in the VS is frequently higher than has generally been thought. For example, it is 10.5 additional years (+/- 2 years) for a 15-year-old patient who has been in the VS for 1 year, and 12.2 years for a 15-year-old patient who has been in the VS for 4 years.