Participates
The study was a retrospective cohort study (clinical trial registration number: NCT04027751). We carefully selected participants from the Beijing Chaoyang Hospital, Capital Medical University. Recruitment started in September 2019 and was completed in March 2020. The study was approved by the Regional Ethical Review Committee at the hospitals and followed the Declaration of Helsinki (2019-ke-273).
Participants were recruited according to the following inclusion criteria: aged between 18 to 85 years older, able to read, write and understand; willing and able to complete pre and postoperative surveys; were admitted and had surgery in Beijing Chaoyang Hospital. Exclusion criteria included the following: diagnosed with sleep disorders previously and had a history of medication for that; using antidepressant or antipsychotic drugs; using sedatives preoperatively; ambulatory, non-general anesthesia surgery or cancellation of surgery; a history of substance abuse; history of prescription or supplemental sleeping aids; clinical (such as mucositis, severe pain, nausea, dyspnea, vomiting) and emotional (crying, apathy, aggression) conditions, which would prevent participates from taking part in an interview; did not consent to fill out questionnaires. These were evaluated from the interview at the moment of the data collection.
The researcher asked the potential participants if they felt comfortable answering questions at that time, and informed them that they were free to refuse participation. All patients signed a written consent to participate in this research. The participants were interviewed one day before the operation, end of the operation, two days after the operation and three days after the operation. A sample of 299 patients was enrolled. Patients were divided into two groups according to whether they had insomnia postoperatively, group A (insomnia, N=78) and group B (without insomnia, N=221). This study tried to explore several research questions regarding sleep condition preoperative and depression, anxiety, cognition and as well as the surgical prognosis.
Tools
Additionally, The presence of sleep disturbances was evaluated by the Insomnia Severity Index (ISI). Sleep continuity was included with objective measures. The ISI is a tool for measuring sleep impairment which permits unrestricted use and distribution. The items are scored from 0 to 28, with higher scores indicating worse sleep quality. The ISI contains seven items on sleep problems (i.e. trouble falling asleep, waking up during the night, waking up earlier than planned, and troubles getting back to sleep) and sleeps quality during the past month (scale 0–4). ISI is a valid screening instrument for detecting insomnia among patients [7], and we defined insomnia as a score of 8-28 (mild: 8-14; moderate-severe: 15-21; severe: 22-28).
Patient Health Questionnaire (PHQ)-9 is a tool to screen and diagnose the degree of depression. It includes 9 items and is used to measure the sense of how people view their life and how they use their resistance resources to maintain and develop their health. Each item of the PHQ-9 is rated on a 4‐point scale, for a total score ranging from 0 to 27. Higher scores indicate increased severity of symptoms and an increased likelihood of major depressive disorders. The PHQ-9 is designed validity and utility to diagnose depression and is efficient to use [8, 9].
Generalized Anxiety Disorder (GAD) -7 is a widely used measure of the worry characteristics of anxiety disorders and is being increasingly used in research and clinical practice [10]. Patients rate their frequency of symptoms within the last two weeks on a four-point scale ranging from "not at all" to "almost every day". The GAD-7 consists of 7 items and ranges from 0 to 21 with higher scores indicating higher GAD symptomatology. The GAD-7 scale is an adequate diagnostic accuracy, validated, brief, a self-administered tool to screen, rate, and monitor the outcome of anxiety disorders in primary healthcare setups [11].
We used Montreal Cognitive Assessment (MoCA) to screen of cognitive disorder. It involves attention, concentration, executive function, memory, language, etc. The MoCA includes 11 items and ranges from 0 to 30. The MoCA is more sensitive than the MMSE in detecting mild cognitive impairment and it more extensively tests executive function [12].
Visual Analogue Scale (VAS) is used to evaluate the severity of pain in patients, with the lowest point of 0 as “no pain at all” and the highest points of 10 as “my pain is as bad as it could be”. The VAS has been proved to be an effective and reliable method to evaluate acute and chronic pain especially in elderly patients.
The PHQ-9, the GAD-7, the ISI and the MoCA were assessed at the baseline. The VAS was assessed preoperatively, at the end of the surgery, one day after surgery, two days after surgery and three days after surgery. The PHQ-9, the GAD-7 and the ISI were reassessed three days after surgery.
Data collection
Patients provided information on sociodemographic variables at enrolment. Demographic data were collected including gender, age, years of education, body mass index (BMI), history of diabetes, hypertension, smoking and drinking, type of surgery, American Society of Anesthesiologists (ASA) classification, operation time, intraoperative urine volume, blood loss, the use of the patient-controlled analgesia, the incidence of postoperative nausea and vomiting (PONV) and the length of hospital stay in addition to the scales above.
Statistical analysis
Data management and statistical analyses were performed in SPSS Statistics software version 25 (IBM Corp., Armonk, NewYork, United States). The data were presented as means±standard error (SEM) for continuous variables if normally distributed, as median (minimum, maximum) if not and as percentages (%) for categorical variables. An Independent-sample t-test was used for continuous variables and the chi-square test was used for categorical variables. Furthermore, we used an ISI scale score cut-off of 7 for expressing sleep impairment in a clinically applicable way and for quantifying its risks associate with health status and disease severity. The observed distributions in the insomnia were summarized in defined groups based on the scores from ISI as follows: none (0-7), mild (8-14), moderate (15-21), severe (22-28). Depression was rate on PHQ-9 of five levels: none (0-4), mild (5-9), moderate (10-14), moderate-severe (15-19),severe (20-27). Anxiety was graded according to the score of the GAD-7: none (0-4), mild (5-9), moderate (10-13), moderate-severe (14-18), severe (19-21). And cognition impairment was scaled by the MoCA: none (26-30); mild (18-25), moderate (≤17).
A binary logistic regression analysis was conducted to assess which factors were significantly associated with insomnia. Receiver operator characteristic (ROC) curves were created by plotting sensitivity against 1−specificity and assessing the total area under the curve for each scale. A P value less than 0.05 in two sides was adopted as the critical level for all tests. All participants provided written informed consent and ethical approval was provided by the local medical ethics committee of the Beijing Chaoyang Hospital, Capital Medical University.