Cognitive function, mental health, and health-related quality of life after lung transplantation

Abstract

Rationale: Cognitive and psychiatric impairments are threats to functional independence, general health, and quality of life. Evidence regarding these outcomes after lung transplantation is limited.

Objectives: Determine the frequency of cognitive and psychiatric impairment after lung transplantation and identify potential factors associated with cognitive impairment after lung transplantation.

Methods: In a retrospective cohort study, we assessed cognitive function, mental health, and health-related quality of life using a validated battery of standardized tests in 42 subjects post-transplantation. The battery assessed cognition, depression, anxiety, resilience, and post-traumatic stress disorder (PTSD). Cognitive function was assessed using the Montreal Cognitive Assessment, a validated screening test with a range of 0 to 30. We hypothesized that cognitive function post-transplantation would be associated with type of transplant, cardiopulmonary bypass, primary graft dysfunction, allograft ischemic time, and physical therapy post-transplantation. We used multivariable linear regression to examine the relationship between candidate risk factors and cognitive function post-transplantation.

Measurements and main results: Mild cognitive impairment (score, 18-25) was observed in 67% of post-transplant subjects (95% confidence interval [CI]: 50-80%) and moderate cognitive impairment (score, 10-17) was observed in 5% (95% CI, 1-16%) of post-transplant subjects. Symptoms of moderate to severe anxiety and depression were observed in 21 and 3% of post-transplant subjects, respectively. No transplant recipients reported symptoms of PTSD. Higher resilience correlated with less psychological distress in the domains of depression (P < 0.001) and PTSD (P = 0.02). Prolonged graft ischemic time was independently associated with worse cognitive performance after lung transplantation (P = 0.001). The functional gain in 6-minute-walk distance achieved at the end of post-transplant physical rehabilitation (P = 0.04) was independently associated with improved cognitive performance post-transplantation.

Conclusions: Mild cognitive impairment was present in the majority of patients after lung transplantation. Prolonged allograft ischemic time may be associated with cognitive impairment. Poor physical performance and cognitive impairment are linked, and physical rehabilitation post-transplant and psychological resilience may be protective against the development of long-term impairment. Further study is warranted to confirm these potential associations and to examine the trajectory of cognitive function after lung transplantation.

Figure 1.

Enrollment for Cognitive Outcomes after Lung Transplantation (COLT) study.

Figure 2.

Relationship between graft ischemic time (minutes) and cognitive scores (Montreal Cognitive Assessment score, range 0–30) depicted as scatter plot and fitted relationship of predicted cognitive scores using fractional polynomial regression. CI = confidence interval.