This research is a descriptive correlation study (Belongs to cross-sectional study). The study was conducted following the Declaration of Helsinki, and all protocols were approved by the Ethical Committee of the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
The choice of research subjects
The research subjects were adult post-liver transplantation patients, and the subjects were selected as follow-up patients after liver transplantation in the out-patient follow-up office of the Department of Hepatobiliary Surgery of First Affiliated Hospital of Xi'an Jiaotong University from October 2015 to October 2017.
The inclusion criteria of the research subjects
a. Age ≥18; b. at least one month after liver transplantation; c. Full reading comprehension ability; c. Normal conscious mental state; and d. Voluntarily participated in the survey.
The exclusion criteria of the research subjects
a. Multiple organ transplantation; b. Secondary liver transplantation; c. Patients with severe heart, lung and kidney diseases; d. Patients with severe mental disorders.
Sample size calculation
This study belongs to the present situation investigation. There are approximately 50 cases of liver transplantation in the Department of Liver Transplant Center of First Affiliated Hospital of Xi'an Jiaotong University every year. Data have shown that the 1-year cumulative survival rate after liver transplantation in adults was 78.13%, 65.81% in 3 years, and 59.25% in 5 years. Thus, according to actual conditions, this study collected the greatest amount of data possible from 105 cases of liver transplantation data.
General information questionnaire
The researchers and included age, gender, education level, occupation, marital status, per capita income, medical expense burden, operation time, complication status, and number of postoperative hospitalizations designed the general information questionnaire.
Social support rating scale (SSRS)
The SSRS was used to measure the social support degree of individuals. The SSRS includes 10 items, consisting of three dimensions, including objective support (3 items), subjective support (4 items) and utilization degree of social support (3 items). Objective support was 0.825, subjective support was 0.849, support utilization was 0.833 and the total was 0.69. The correlation coefficient of the subscale and the total scale was 0.724 ~ 0.835, indicating that the scale content validity was higher. The correlation coefficient between the subscales was 0.462 ~ 0.664, lower than that between the total tables, indicating that the scale had higher structure validity. The retest reliability in this study was 0.666.
Quality of life questionnaire for liver transplantation recipients in Chinese (pLTQ)
Saab and colleague  created a profession questionnaire in 2010 called pLTQ, which included 32 items in eight fields, and the overall Cronbach's rating was 0.93. Each option was divided into 7 grades: always, most of the time, more time, sometimes, occasionally, almost none, and never, ranging from 1 to 7 points, respectively; the higher the score, the better the quality of life. Researchers sinicized the questionnaire and studied its reliability and validity in 2015. The Chinese version of the pLTQ included six dimensions, such as concern (8 items), physical function (5 items), emotional function (4 items), economy (3 items), health services (5 items) and complications (3 items), for a total of 28 items and 28 ~ 196 points. The result of the content validity index (s-cvi /Ave) of the scale was 0.93, and the six dimensions were worry (0.895), physical function (0.763), emotional function (0.810), economy (0.879), health services (0.725), complications (0.708), and overall (0.939). The retest reliability was 0.713. The Chinese version of the pLTQ had good applicability and evaluation performance in Chinese liver transplantation recipients and can be used in Chinese liver transplantation recipients' quality of life surveys. The retest reliability in this study was 0.917.
Data collection methods
The team of researchers completed the data collection. Importantly, researchers obtained consent from the Department of Liver Transplant Center of First Affiliated Hospital of Xi'an Jiaotong University before beginning the investigation. First, researchers clarified the purpose of the study, the content, the nature of commitment to research, the confidentiality, and the exclusion of private interests, and they obtained permission from the respondents. Then, researchers handed out questionnaires and explained the matters requiring attention to patients. Next, the patients filled out the questionnaire themselves. When filling in the form, the researchers assisted the patients with explanations. It took 15 to 30 minutes to complete the survey, and the questionnaire was collected on the spot. After the questionnaire was returned, the patient's medical records were found according to the patient's hospitalization number, and part of the questionnaire was additionally filled. Authors had no access to information that could identify individual participants during or after data collection. Then the follow-up analysis and manuscript writing were carried out immediately (from October 2017 to March 2018).
EpiData3.1 was used to establish the database. SPSS 18.0 was used for the analysis. Statistical methods included descriptive statistical analysis, chi-square test, t test, variance analysis and correlation analysis. P<0.05 was considered statistically significant.