BackgroundWith 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.MethodsBetween 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.ResultsWith regard to the SGRQ, there were significant differences in the forced expiratory volume in 1 s (FEV1) (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), FEV1(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).ConclusionsDyspnea 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.