Factors associated with quality of life in patients receiving lung transplantation: a cross-sectional study

BACKGROUND: With improved prognosis after lung transplantation (LTx), improving health-related quality of life (HRQL) in patients who have undergone LTx is a key goal. Although HRQL is improved significantly after transplantation, it is poorer than that in ordinary healthy people. However, the factors associated with poor HRQL remain unclear. This cross-sectional study aimed to identify the factors associated with poor HRQL in patients who have undergone LTx. METHODS: Between December 2018 and May 2022, 80 patients who had undergone LTx completed St. George’s Respiratory Questionnaire (SGRQ) as a disease-specific quality of life measure, the Short Form-12 (SF-12) as a generic quality of life measure, and modified Medical Research Council (mMRC) scale of dyspnea. The groups were assigned according to the median SGRQ-total score and the Japanese population standard for SF-12, and those with good HRQL were compared with those with poor HRQL. Independent factors were evaluated using multivariate analysis. RESULTS: With regard to the SGRQ, there were significant differences in the forced expiratory volume in 1 s (FEV(1)) (P = 0.041), use of bronchodilators (P = 0.026), 6-min walk distance (6MWD) (P < 0.001), and Mmrc (P < 0.001) between better and poorer HRQL. For the SF-12 physical component summary score (PCS), age (P = 0.017), sex (P = 0.011), FEV(1) (P < 0.001), forced vital capacity (FVC) (P < 0.001), diagnosis (P = 0.011), handgrip force (P = 0.003), 6MWD (P < 0.001), and Mmrc (P < 0.001) varied. Multivariate analyses revealed that Mmrc was the only independent factor in the SGRQ (P < 0.001, odds ratio [OR] = 6.65, 95% confidence interval [CI]: 2.49–17.74) and SF-12 PCS (P = 0.001, OR = 0.185, 95% CI: 0.07–0.52). There were significant correlations between the SGRQ-Total score and SF-12 PCS (correlation coefficient = -0.612, P < 0.001). CONCLUSIONS: Dyspnea may be an independent factor of poor disease-specific and generic HRQL in LTx patients. The management of dyspnea may improve the HRQL in patients who have undergone LTx.