Estimation of quality-adjusted life expectancy in patients under prolonged mechanical ventilation

Objectives: The purpose of this study was to estimate the quality-adjusted life expectancy(QALE) and the expected lifetime utility loss of patients with prolonged mechanical ventilation(PMV).Methods: PMV was defined as more than 21 days of mechanical ventilation. A total of 633patients fulfilled this definition and were followed for 9 years (1998-2007) to obtain theirsurvival status. Quality of life of 142 patients was measured with the EuroQol five-dimensional(EQ-5D) questionnaire during the period 2008 to 2009. The survival probabilities foreach time point were adjusted with a utility measurement of quality of life and then extrapolatedto 300 months to obtain the QALE. We compared the age-, gender-matched referencepopulations to calculate the expected lifetime utility loss.Results: The average age of subjects was 76 years old. The life expectancy and loss of lifeexpectancy were 1.95 years and 8.48 years, respectively. The QALE of 55 patients with partialcognitive ability and the ability to respond was 0.58 quality-adjusted life years (QALY),whereas the QALEs of 87 patients with poor consciousness were 0.28 and 0.29 QALY for theEQ-5D measured by family caregivers and nurses, respectively. The loss of QALE for PMVpatients was 9.87 to 10.17 QALY, corresponding to a health gap of 94% to 97%.Conclusions: Theses results of poor prognosis would provide stakeholders evidence forcommunication to facilitate clinical decisions. The estimation may be used in future studiesto facilitate the cost-effectiveness and reduction of the health gap.