Ninety-three patients undergoing regular PD for more than 3 months at the Department of Nephrology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from April 1, 2019 to November 1, 2019 met the inclusion criteria for the self-management ability and MIAS correlation study. Patients who did not meet the following criteria were excluded: 1. age less than 18 years; 2. duration of dialysis shorter than 3 months; 3. cognitive dysfunction, malignant tumor or chronic infection, such as tuberculosis or hepatitis B; and 4. acute infection, severe cardio-cerebro vascular event history, surgery or trauma within one month before the data collection. All patients received the same predialysis patient education and postdialysis management at our center and agreed to participate in the study. We collected blood samples to assess serum C-reactive protein (CRP), albumin, prealbumin, creatine (Cr), cholesterol, triglycerides, calcium, phosphorus, potassium, serum intact parathyroid hormone (iPTH), serum ferritin, transferrin, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) upon admission to the hospital for the PD assessment during the study period. All laboratory measurements were carried out at the Ninth People's Hospital Laboratory using standardized and automated methods. We also collected demographic and biochemical data, such as the number of hospitalizations, diabetes, and peritonitis, which were diagnosed according to the recommendations of the ISPD when at least 2 of the following were present: (1) clinical features consistent with peritonitis, i.e., abdominal pain and/or cloudy dialysis effluent; (2) dialysis effluent white cell count > 100/µL or > 0.1*109/L (after a dwelling time of at least 2 hours) with > 50% polymorphonuclear; and (3) a positive dialysis effluent culture .
Self-management scale for PD patients
The self-management scale for PD patients was designed by our research team. The scale includes Medication Compliance (4 items), Dietary Management (4 items), Recognition of Dialysis Complications and Adequacy Evaluation (6 items), Dialysis Effect Evaluation and Monitoring (3 items), and Peritoneal Standardized Operation (6 items), for a total of 5 dimensions and 23 items. Each item is scored on a 4-point Likert scoring (i.e., "Not at all", "Basically okay", "Mostly okay", and "No problem" or "Unclear", "Basic understanding", "Moderate understanding", and "Full understanding", which correspond to 0, 1, 2, and 3 points, respectively). There are no reverse-scored items. The total score ranges from 0 to 69 points. The higher the score, the better the self-management ability. The total scale score is the sum of the items in each dimension. The purpose and significance of the survey were explained by researchers familiar with the questionnaire before the data were collected. The researchers assisted those who had difficulty reading. The questionnaire's reliability test results were as follows: the Cronbach's alpha coefficient was 0.912. In the validity analysis, the correlation coefficients of each factor and the total scale score were statistically significant with P less than 0.05.
The assessment of self-management ability is a tool used to determine whether patients are independent and do PD safely at home. As explained above, the standardization of the operation ability (such as standard sterility PD exchange, hand hygiene, and exit-site care) must be regularly monitored to avoid PD-related infection and identify changes in volume (such as blood pressure, weight, urine volume, and edema) to avoid fluid overload. We also need to monitor their diet management abilities to maintain a good nutritional status and medicine management abilities to avoid adverse drug reactions and identify PD-related complications (such as the identification of peritonitis symptoms, ductal dysfunction and inadequate dialysis symptoms) in a timely manner. All these evaluation indicators could directly affect the adjustment of the PD prescription.
However, there is no internationally standardized scale for the evaluation of the self-management abilities of PD patients. Xiaohua Wang et al. designed a continuous ambulatory peritoneal dialysis patient self-management scale including 28 items and 5 dimensions, namely, solution bag replacement, troubleshooting during operation, diet management, complication monitoring, emotion management and return to social life . To make it easier for the patients to understand and ensure that the content is more comprehensive, we deleted and added some content based on the existing scale. We simplified the troubleshooting during the operation dimension and complication monitoring dimension and combined these dimensions into the Dialysis Effect Evaluation and Monitoring dimension; the Recognition of Dialysis Complications and Adequacy Evaluation dimension was designed to replace the emotional management and return to social life dimension, and we added the Medication Compliance dimension to evaluate the medication management ability. Our scale paid more attention to evaluating self-management consciousness during daily dialysis operations (see the appendix for details, Additional file 1).
Assessment of MIAS
MIAS is a complex involving malnutrition, inflammation, and atherosclerosis, and MIAS is divided into MIAS0, MIAS1, MIAS2, and MIAS3 based on the presence of zero, one, two, and three components, respectively [7, 10]. We used the MIS to evaluate malnutrition. The score includes 4 aspects, including relevant medical history, physical examination, and laboratory indicators (BMI, plasma albumin, and transferrin). In total, there are 10 items; each item is scored from 0 to 3 to indicate the severity from mild to severe, and a higher total score indicates more severe malnutrition. A total score less than 7 indicates a well-nourished state, and a score greater than 7 indicates malnutrition. Inflammation was indicated by CRP ≥ 10 mg/L because the normal range in this center is less than 10 mg/L. Atherosclerosis was defined as the presence of one of the following conditions: 1. a previous medical history of coronary heart disease, acute myocardial infarction, cerebral infarction, or cavity cerebral infarction; 2. cervical artery or lower limb artery ultrasound showing plaque formation; and 3. cranial computed tomography/magnetic resonance imaging (CT/MRI) and chest CT showing intracranial infarction or coronary calcification. Therefore, according to the answer “yes” regarding whether the MIS was > 7 points, CRP was ≥ 10 mg/L, and atherosclerosis-related history or examination results were present, the patients were divided into the MIAS0, MIAS1, MIAS2, and MIAS 3 groups. Patients with more than one MIAS factor were combined as MIAS (1–3).
After collecting the data, a dedicated researcher was responsible for the data input and verification and used EpiData3.1 to establish a database and SPSS23.0 (Chicago, IL, USA) for the statistical analysis. Student's t-test, Mann-Whitney U test and χ² test were used to compare the normally distributed, nonnormally distributed and categorical data, respectively. The continuous variables are presented as the mean ± standard deviation, and the categorical variables are shown as frequencies with percentages. Pearson and Spearman correlation analyses were used to assess the correlations between the parametric and nonparametric data, respectively. Statistical significance was indicated by P values < 0.05.