Study design and setting
This is a retrospective observational study, the present study recruited 88 consecutive patients who underwent multiple myeloma and received CAR-T therapy from the Center for Hematology and Bone Marrow Transplantation of The First Affiliated Hospital, Zhejiang University School of Medicine, China, between July 2018 and September 2021.
Participants and data collection
Criteria for selecting the subjects were as follows: a) diagnosed as multiple myeloma according to Chinese Guideline for Diagnosis and Treatment of Multiple Myeloma [16]; b) ≥ 18 years old; c) treated with BCMA CAR-T therapy; d) volunteered to participate in this study and signed an informed consent prior to the study. Participants who had a history of digestive tract reconstruction or were subjected to diseases accompanied with diarrhea were eliminated.
Demographic data were obtained from questionnaires and clinical data from electronic medical record (EMR) system. The questionnaires, which collected demographic information (age, sex, BMI, course of disease, etc.) and clinical data (Durie-Salmon staging, Durie-Salmon typing, previous treatment lines, type of monoclonal immunoglobulin, etc.) were personally administered at inpatient facilities. All members of this program received the training sessions regarding utilization of measures and data collection, and both of them were proficient in EMR system and assessment tools. In the course of data input and analysis, this study was supervised by two professionals per one or two weeks.
Instruments
Sociodemographic and clinical characteristics
The demographic data of all participants were collected for the following variables: gender, age, weight and height. In addition, clinical data, including diagnosis, Durie-Salmon staging, Durie-Salmon typing, previous treatment line, severity of CRS, a history of autologous transplantation, time of hospitalization, performance status, were extracted from EMR system.
Non-infectious diarrhea
According to the industry standard of Ministry of Health of the PRC [17], non-infectious diarrhea refers to bowel movements are more than three times per day without abdominal pain or fever, and stool routine results indicated normal.
Performance status
Physical State of Eastern Cooperative Oncology Group (ECOG) [18] was compiled by Eastern Cooperative Oncology Group, which is widely used in patients with cancer. Patients are asked to select the statement that was closest to their own current state of physical ability and activity. There are five degrees, which ranged from “I am fully active and able to carry out activities as I did before my cancer diagnosis, without any restriction” to “I am completely disabled, cannot carry on my self-care, and I am confined to a bed or chair”. The higher levels, the worse physical state.
Cytokine Release Syndrome
Grading for CRS [19] was made by American Society for Transplantation and Cellular Therapy (ASTCT) The main indicators include fever, hypotension and hypoxia. Grade 1 indicates the temperature of patients ≥ 38℃; grade 2 shows the low-flow nasal catheter oxygen inhalation (oxygen flow ≤ 6 L/min) based on the level 1; grade 3 represents that patient’s body temperature ≥ 38℃ and requires the use of vasopressin and high-flow nasal catheter, mask or Venturi inner mask. The difference between grade 4 and grade 3 is that hypoxia requires positive pressure ventilation, such as CPAP, BiPAP, intubation and mechanical ventilation; grade 5 means death of patient. Severity of CRS ≥ grade 3 indicates severe.
Nutritional status
Body Mass Index (BMI) is an important index recommended by WHO to evaluate the nutritional status of the body. Calculation method: BMI = weight (kg)/ height (m)2. According to Chinese adults, BMI < 18.5, 18.5–23.9, 24.0−27.9 and BMI ≥ 28.0 indicate low weight, normal, overweight and obesity, respectively [20].
Data analyses
The Statistical Package for the Social Sciences version 25.0 (IBM Corporation, Armonk, NY, USA) was used to process and analyze data. Descriptive statistics was employed to analyze clinical and demographic data of patients. Univariate analysis was used to test the relationships between sociodemographic and clinical parameters, non-infectious diarrhea. Based on the results of univariate analysis, multiple logistic regression analysis further identified the risk factors for non-infectious diarrhea. All analyses considered two-tailed p value of < 0.05 to be statistically significant.
Ethical consideration
Ethical and operational approval for this study was granted by the Institutional Review Board of The First Affiliated Hospital, Zhejiang University School of Medicine (Approval Number: ChiCTR1800017404).