This was a retrospective cohort study conducted from September 2021, to February 2023. Patients with ≥3 web-based consultations formed the internet hospital group; similarly, those with ≥3 in-person consultations formed the physical hospital group. Both internet hospitals and physical hospitals could provide patients with appointment registrations, prescriptions, drug adjustments, and other services. The West China Internet Hospital was the web-based platform of the West China Hospital of Sichuan University. The hospita linked patients with medical services through the two software platforms of the West China Hospital of Sichuan University, the WeChat official account and the Huayitong app (version 7.0.4), so that patients could have access to convenient, high-quality, and efficient professional medical services anytime and anywhere.

Patients with chronic pain who attended the outpatient clinic of the Pain Department of West China Hospital of Sichuan University from September 2021, to February 2023, were enrolled. The basic information of the patients, including age, sex, disease diagnosis, number of visits, visit time, consultation with an internet hospital or physical hospital, and contact information was obtained from the IT center of West China Hospital of Sichuan University. Then, we screened patients according to the inclusion and exclusion criteria, and propensity score matching (PSM) was performed for patients after screening according to sex, age, number of visits, and diagnosis. A telephone follow-up was conducted for the matched patients. The matched patients were asked to complete the Brief Pain Inventory (BPI) by telephone [32,33]. Moreover, the patients’ medical expenses, satisfaction, and occurrence of adverse drug events were also recorded by telephone follow-up.

The inclusion criteria were a pain duration or recurrence of ≥3 months, adults aged between 45 and 64 years, and ≥3 hospital visits. Patients with ≥3 pain clinic visits that were exclusively web-based formed the internet hospital group. Similarly, those with ≥3 pain clinic visits that were exclusively in-person formed the physical hospital group. The exclusion criteria were patients with mental illness; cognitive, vision, hearing, expression, or communication impairment; cancer pain; a history of drug abuse; addiction; alcohol abuse; and participation in any other clinical trial or study that affected pain intensity and quality of life (QOL).

The primary outcome was improvement in QOL (QOL score at the last visit – the QOL score at the first visit). The secondary outcomes were patient satisfaction; pain relief rate, which was measured by the numerical rating scale (NRS; [NRS score at the first visit – the NRS score at the last visit]/NRS score at the first visit × 100); incidence of drug-related adverse events (stomach pain, severe constipation, dizziness, pruritus, nausea, and vomiting); and average cost per visit. The QOL score was measured by the QOL assessment part of the BPI. This part contained 7 items, including the impact of pain on patients’ daily life, mood, walking ability, daily work, relationship with others, sleep, and interest in life, with a score of 0‐10 points for each item. A lower score indicated a better QOL.

At present, there are no studies related to outpatient pain management by internet hospitals, and there are no reference research data. Therefore, we conducted a preliminary experiment to calculate the required sample size. In the preliminary trial, 20 patients were included in both the internet hospital group and the physical hospital group according to the inclusion and exclusion criteria. The outcomes of these patients were obtained through telephone follow-up, and the sample size was calculated accordingly. The average difference between the QOL score at the last visit and the first visit was −4.35 (SD 6.12) in the internet hospital group and −9.65 (SD 8.41) in the physical hospital group. The α value was .05, and the β value was .9. The σ was the combined SD, and δ was the difference between the two groups of means. The calculation formula was n = (2[Z_α + Z_β]² × σ²)/δ². Therefore, 56 patients were needed for each group, and considering a 10% loss rate, the final requirement was 64 patients per group.

All analyses were performed using SPSS 27.0 (IBM Corp). We matched the cohorts at a ratio of 1:1 using PSM. We used nearest neighbor matching with a caliper of 0.02, and the covariates were age, sex, disease diagnosis, and number of clinic consultations. For continuous variables such as age and number of visits, the standardized mean difference (SMD) was used to determine whether the match was balanced, with an SMD<0.10 indicating a balanced match [34]. For categorical variables, such as sex and diagnosis, we used an α level of .05 for the χ² test to indicate that the match was balanced. Means, SDs, medians, IQRs, and percentages were used to describe the data. A 2-tailed t test was used for normally distributed data, the Wilcoxon signed rank-sum test was used for nonnormally distributed data, and the χ² test or Fisher exact probability method was used for count data.

This study was approved by the Ethics Committee on Biomedical Research of the West China Hospital of Sichuan University (approval number: 2022 Review 467). The registration number in the Chinese Clinical Trial Registry was ChiCTR2200059152. Informed consent forms were signed by all patients who were followed up. The original data generated and analyzed in this study, such as the patient’s name, ID number, and home address, were anonymized. The study did not involve compensation for the enrolled patients.

The flow chart of the sample selection process is shown in Figure 1. From September 2021, to February 2023, there were a total of 51,575 outpatient visits. After excluding repeated visits, a total of 28,062 patients consulted the outpatient clinic during the day, including 3653 patients in the internet hospital group and 24,409 patients in the physical hospital group. After applying the inclusion and exclusion criteria, 3531 patients in the internet hospital group were excluded, and 23,670 patients in the physical hospital group were excluded. After 122 patients in the internet hospital group and 739 patients in the physical hospital group underwent PSM, 88 patients in each group were followed up by telephone. Of these patients, 11 were lost to follow-up in the internet hospital group, while 6 patients were lost to follow-up in the physical hospital group. Finally, both the internet hospital group and the physical hospital group included 77 patients for analysis.

Before the PSM was performed, there was not a significant difference in sex, age, or number of visits between the internet or physical hospital groups, but there was a significant difference in diagnosis (P<.001). Only significant differences in specific diseases that persisted after matching are shown. After PSM, there were no significant differences in sex, age, diagnosis, or number of visits between the two groups (Table 1). In addition, there were no statistically significant differences in education level, disease duration, or baseline QOL scores. The baseline NRS score of the internet hospital group was significantly higher than that of the physical hospital group (P<.001; Table 2). After PSM, a P>.05 and an SMD<0.10 for sex, age, number of visits, and disease diagnosis between the two groups indicated that the matching was balanced.

There was not a significant difference in the QOL score between the internet hospital group and the physical hospital group at the first visit (P=.19) or the last visit (P=.20). The difference in the QOL score between the last visit and the first visit was also not statistically significant between the two groups (P=.80; Figure 2). However, there was a significant decrease in the QOL score from the first visit to the last visit for the internet hospital group (P<.001). Similarly, there was a significant decrease in the QOL score from the first visit to the last visit for the physical hospital group (P=.001; Figure 2).

There was not a significant difference in the pain relief rate (40.31% for internet hospital vs 34.11% for physical hospital P=.25) or the incidence of adverse drug events (26% for internet hospital vs 23% for physical hospital; P=.60) between the two groups, and the most common adverse events were constipation, dizziness, and cardialgia (Figure 3). In addition, there was a significant difference in patient satisfaction between the two groups (P=.01). More patients in the internet hospital group were very satisfied, and more patients in the physical hospital group were satisfied (Table 3).

The median average cost per visit for patients in the internet hospital group was 130 yuan (US $17.87), while that in the physical hospital group was 410 yuan (US $56.35), and there was a significant difference between the two groups (P<.001). The expenses for the internet hospital group were all medicine-related expenses, while the physical hospital group also had travel, accommodation, and meal expenses in addition to medicine-related expenses. The median medical expense of patients in the physical hospital group was 300 yuan (US $41.23), which was significantly different from the 130 yuan (US $17.87) in the internet hospital group (P<.001; Table 3).

This was a retrospective cohort study that compared the effectiveness of chronic pain management between internet hospitals and traditional physical hospitals and revealed that both internet and physical hospitals could improve the QOL of patients with chronic pain. Patients using internet hospitals had a greater satisfaction and lower costs. However, there was no difference in the rate of pain relief and the incidence of adverse drug events between the two groups.

The distribution of medical resources is uneven in China, and high-quality medical resources are often concentrated in economically developed areas [35]. Research shows that the availability of medical resources has an impact on the use of mobile health care [36]. When visiting an outpatient clinic, patients have problems, such as long travel distances, difficult registration, long waiting times, and high costs, and one visit often cannot solve all of their health-related problems [37]. Patients with chronic pain need long-term multimodal pain management to relieve pain and reduce the occurrence of breakthrough pain.

Mobile medical apps for pain are currently in use, and some studies have shown that using mobile medical apps to manage pain can improve patients’ QOL and relieve pain [38-40]. For the management of chronic pain outside the hospital, mobile medical apps can be specially developed for a certain type of pain with high specificity, which can help patients with pain monitoring and evaluation, exercise rehabilitation, knowledge dissemination, and more. However, most mobile medical apps lack the participation of professional pain doctors and cannot provide patients with disease diagnosis, prescription issuance, drug adjustment, appointment booking, or other services. Moreover, mobile medical apps lack supervision to ensure their quality and accuracy and lack reliable evidence-based guidance on their use. In addition, the security of patients’ information is also a concern [16,41,42].

As a comprehensive platform, internet hospitals cover mobile medical apps and telemedicine. They rely on physical hospitals and can exercise some functions of physical hospitals. Internet hospitals can provide patients with services such as disease reviews, diagnosis and treatment, prescription issuance, and drug delivery. When patients’ pain worsens, they can make web-based appointments for offline diagnosis, treatment, examination, and hospitalization. More importantly, internet hospitals can also provide remote psychological care for patients, which is good for patient’s pain management [43]. To achieve the closed-loop management of patients inside and outside of the hospital, we described the functions of an internet hospital in our previous study [24].

Previous studies have shown that approximately 12.9% of patients choose internet hospitals for outpatient pain management, and the majority of patients in pain clinics are middle-aged patients (45‐64 years old) [24]. It is considered that older patients have problems with smartphone use and comprehension, and young patients mostly experience acute pain. This study was carried out among middle-aged patients. Considering the smooth communication with patients with cancer and their survival, they were excluded, as well as patients with mental illness or cognitive, vision, hearing, expression, or communication impairments.

In this study, patients’ QOL generally improved after outpatient pain management at both internet hospitals and physical hospitals. This finding is similar to those of several previous studies. Li et al [44] indicated that internet-based pain interventions for patients with chronic postoperative pain resulted in improvements in QOL and satisfaction similar to traditional face-to-face interventions. Buonanno et al [17] showed that telemedicine could provide high-quality assistance for patients with cancer-associated pain similar to face-to-face visits. Therefore, internet hospitals are effective ways to improve the QOL of patients with chronic pain, similarly to physical hospitals.

Patients in both groups received the guidance of pain doctors for medication, and there was not a significant difference in the incidence of adverse drug events between the groups, indicating that internet hospitals are a feasible way to guide patients with chronic pain in medication management and are not inferior to traditional face-to-face hospitals. In addition, most patients of internet hospitals were very satisfied, while patients of physical hospitals were just satisfied, which may have been due to travel fatigue, a long queue, crowded treatment areas, and time spent in the process of physical hospital treatment.

With internet technology as the carrier, one of the greatest advantages of internet hospitals is that patients can be treated at home, which further reduces the cost of patient travel, accommodation, and meals. A previous systematic review and meta-analysis found that, in terms of cost-effectiveness, 39% of studies determined that telemedicine was more cost-effective [18]. Our study revealed that the total expenses for patients of internet hospitals were lower than that for patients of physical hospitals. Although there was a reduction in nonmedical costs for patients, internet hospitals cannot provide patients with physiotherapy, nerve blocking treatment, or other similar treatments and can only adjust medication for patients. This further indicates that the current internet hospital model is suitable for patients with mild pain, stable conditions, and for follow-up visits. However, for the baseline comparison, we found that patients in the internet hospital group had higher NRS scores than those in the physical hospital group, possibly because patients could see a doctor immediately when their pain worsened via internet hospitals, while physical hospitals required appointments that may have occurred when pain levels were not at their peak.

At present, the treatment of chronic pain is mainly based on multimodal analgesia. Since an internet hospital is a carrier of multimodal analgesia for chronic pain, one of its advantages is that it can be visited anytime and anywhere through a variety of smart devices, and internet hospitals can be combined with other digital medical technologies, such as wearable devices, for at-home follow-ups. The implementation of multimodal analgesia by internet hospitals is mainly through the following: first, similar to traditional offline treatment, the patients have a web-based follow-up to assess their conditions, so as to adjust the use of medication; second, jointly with the psychological clinic for patients to conduct psychological counseling, patients are taught how to face pain and how to use mindfulness therapies; third, according to the patients’ conditions, the patients are given offline physiotherapy or invasive intervention treatment appointments at appropriate times, and those with serious conditions can directly apply for web-based admission procedures. In conclusion, the current internet hospital as a platform or a new management implementation pathway, can help patients and doctors maintain a long-term relationship, which is conducive to the stable implementation of treatment.

This study is the first to explore and verify the effectiveness of internet hospitals for managing chronic pain and our findings will help promote the use of internet hospitals for outpatient chronic pain management. Internet hospitals can be used as a part of the standardized closed-loop management of chronic pain, but they are still in the development stage for chronic disease management and cannot actively intervene in patients’ conditions or carry out continuous disease monitoring. In the future, more chronic disease management models need to be further developed for different chronic diseases.

This study had some limitations. First, this was a retrospective cohort study, and relevant scales and data were obtained through telephone interviews with patients, which may have led to a recall bias and cognitive biases. Second, we did not collect information on pain severity, pain location, and the types of drug use before matching, so PSM did not use this information as a covariate, which may have affected the reliability of some of the results. Meanwhile, we did not collect the time interval between patients’ visits, which may have had an impact on treatment effectiveness. In addition, the patients in the internet hospital group could only receive drug treatment through the internet, while some patients in the physical hospital group could receive both drug treatment and non–drug treatment, and we did not exclude these patients, which may have affected the comparisons for treatment effects. Furthermore, this study selected only patients who visited the pain outpatient department of the West China Hospital of Sichuan University from September 2021, to February 2023. Although the West China Hospital is the most representative hospital in southwest China, this was still a single-center study and may lack representativeness.

Both physical hospitals and internet hospitals could improve the QOL for patients with chronic pain. Meanwhile, patients using internet hospitals had a greater satisfaction and lower costs. Therefore, the internet hospital can be used as one of the multichannel ways of chronic pain management outside of the hospital.