Health-related quality of life in Australasian survivors of H1N1 influenza undergoing mechanical ventilation. A multicenter cohort study

Rationale Patients surviving acute respiratory distress syndrome suffer decrements in physical function and health-related quality of life (HR-QoL) however it is unclear whether HR-QoL is disproportionately affected in those with H1N1 influenza. Objectives The objective was to compare the HR-QoL of patients with a diagnosis of H1N1 influenza who were mechanically ventilated, twelve months following ICU with healthy population data and ICU survivor data. Methods A prospective, observational, binational, multi-centre cohort study was conducted in eleven ICUs in Australia and New Zealand during June-September, 2009. Eligible participants were mechanically ventilated in the ICU with a confirmed diagnosis of H1N1 influenza. People were excluded if aged <18 years or could not speak English. Two validated HR-QoL questionnaires (Short Form-36 Version 2 (SF-36); the Assessment of Quality of Life (AQoL)) were administered one year following ICU. Measurements and main results Sixty-two patients (48 male) had median (IQR) age 42 (29 to 53) years, APACHE II score 18.0 (14 to 20); ventilation days 10.0 (4 to 23); ICU and hospital LOS 12.5 (7 - 27) and 20.0 (15 - 38) days respectively. Hospital mortality was 7 and 31 of the cohort received a tracheostomy. The mean (SD) health utility score at one year was 0.68 (0.30) compared to the healthy age-matched population (0.81 (0.23)). The mean (SD) SF-36 physical and mental component summary scores were within population normal ranges at 44.4 (12.3) and 45.5 (12.5) respectively. Conclusions Health-related quality of life of Australasian survivors of severe H1N1 influenza was comparable to the healthy population one year following ICU discharge. Consensus should be sought on standardization of follow-up time points and outcome measurement. Clinical trial registration The trial was registered with the Australian and New Zealand Clinical Trials Registry available at www.anzctr.org ACTRN12609001037291. Registered December 4th 2009.