Long-Term Quality-of-Life Outcomes in ARDS
Abstract & Commentary
Synopsis: In this study of 132 survivors of an episode of ARDS, somatic and neuropsychiatric symptoms were common. ARDS survivors had poorer quality of life than a comparison group of patients with cystic fibrosis.
Source: Angus DC, et al. Quality-adjusted survival in the first year after the acute respiratory distress syndrome. Am J Respir Crit Care Med. 2001;163:1389-1394.
In this article, Angus and colleagues from the University of Pittsburgh present an interesting and rather eye opening analysis on long-term outcome of patients admitted to the ICU with the acute respiratory distress syndrome (ARDS) as their primary problem. These 200 patients were enrolled during a previous study that looked at effects of inhaled nitric oxide (NO) in patients with ARDS. Patients were enrolled into the study if they met the consensus criteria for ARDS. Patients who had sepsis, multiple organ dysfunction syndrome (MODS) or a high risk for developing it, septic shock, severe head injury, or with severe immunocompromise were excluded. Although the original study was performed to look at effects of inhaled NO, data regarding quality of life and function prior and after the episode of ARDS were also prospectively collected. The analysis of these data is presented in this article.
Health-related quality of life (HRQL) was measured using quality of well-being (QWB) at 6 and 12 months after enrollment. QWB assesses quality of life in terms of function and symptoms. To assess premorbid functional status, the Karnofsky Performance Status index was used. When it was found that the control and therapy groups were similar in baseline characteristics and outcomes, all data were pooled.
Overall, these were young male patients with ARDS as their primary problem. More than half of the patients were medical (56%) and the others were surgical (20%) or trauma (24%). Out of 200, 132 patients survived to leave the hospital. By Kaplan-Meier analysis, 1-month survival was 69.5 ± 5% and 6- and 12-month survival was 55.7 ± 3.7%. Survivors were younger, had higher mean premorbid functional status, and lower mean APACHE II scores at enrollment than nonsurvivors. When the survival was multiplied by QWB to give a measure of quality-adjusted survival, the survival at 1 year was 36 quality-adjusted life years (QALY) per 100 patients with ARDS. Using sensitivity analysis, the best case scenario (no post discharge death) showed a 1-year QALY of 46, whereas, adjusting for lower quality of life during prolonged hospitalization, QALY dropped to 28, 24, and 21 (if quality was considered 0 during hospitalization).
When QWB was compared with a group of patients with cystic fibrosis (QWB 0.76 ± 0.035), a chronic disorder with multisystem problems, patients with ARDS had much lower quality of life (QWB 0.6 at both 6 and 12 months). Age, sex, comorbidity, or APACHE II scores were not associated with HRQL as measured by QWB. There was weak association between premorbid functional status and QWB at 1 year. More than two-thirds of the patients had musculoskeletal symptoms, nearly half had respiratory symptoms, and nearly half of the patients had some elements of neuropsychiatric symptoms (depression, anxiety, or insomnia).
Comment by Uday B. Nanavaty, MD
To a certain extent, this study confirms previous findings regarding ARDS outcomes. It has been shown that if you survive the acute events in ARDS, the mortality reaches a steady state. The teaching in ARDS is still that the longer you live, the longer you live. It has been previously shown that there may be some element of persistent respiratory dysfunction in some patients with ARDS, and that their symptoms tend to improve for up to 6 months and then reach a steady state as well. Such wide variety and such prevalence of symptoms 1 year after an episode of ARDS have not been well described, and this report is truly an eye opener as to the effect of this still highly fatal disorder. It is not clear as to how many patients developed other organ dysfunction during their hospital stay, how much of morbidity and mortality was truly attributable to ARDS, and how much could be attributed to other illnesses that complicate an often prolonged hospital course.
Additional information one might have sought, I suppose, includes the ventilation strategy used, any significant difference between survivors and nonsurvivors, and between survivors with full recovery and survival with persistent symptoms. The other striking finding is that compared to patients with cystic fibrosis, survivors of ARDS perceived their quality of life to be poorer. That is possible because the patients with ARDS may have had a much higher functional status. They may have had higher expectations for themselves when compared to patients with cystic fibrosis, who may have been better adjusted to their diseased state.
Beyond these minor limitations, this study raises an important issue in outcomes in critical care. Are 28-day or 30-day mortality rates adequate measures for outcomes? What are the mechanisms for the persistent symptoms found in these ARDS survivors? Does acute therapy affect these long-term disabilities? If we had thought that we knew the "optimal ventilation strategy" in ARDS to optimize the outcomes in ARDS, this study reminds us of the poet’s line, "miles to go before I sleep."