1. Introduction
Abdominal pain (AP) is a challenging symptom to address in patients with gastroparesis. Abdominal pain has been reported in as many as 79% of patients with gastroparesis [
1]. AP can be debilitating and often negatively impacts the quality of life for these patients. In addition, gastroparesis AP leads to increased emergency department visits and hospitalizations, which increases healthcare utilization and costs [
1,
2]. Abdominal pain in gastroparesis (GP) is a multifaceted symptom that extends beyond delayed gastric emptying alone. While gastroparesis is characterized by impaired stomach motility, the severity of abdominal pain often does not correlate with the degree of delayed emptying, suggesting additional pathophysiological mechanisms [
3]. Speculatively, these may include visceral hypersensitivity, neuroinflammation, and neuropathy within the gastric wall, which could alter pain signaling [
3]. Central sensitization due to prolonged pain exposure, psychological factors such as depression and anxiety, and disruptions in the gut–brain axis further complicate pain perception in GP [
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15]. Addressing abdominal pain effectively may require therapies that not only improve motility but also target these underlying mechanisms, such as symptom modulators (tricyclic antidepressants, pregabalin) and behavioral therapies like cognitive behavioral therapy and hypnotherapy, which have shown promise in managing GP symptoms by potentially modulating these complex interactions [
3].
The treatment of gastroparesis involves dietary modifications, and medicines such as prokinetic agents to enhance gastric emptying and antiemetic agents to reduce nausea and vomiting [
4]. Currently, metoclopramide is the only U.S. Food and Drug Administration (FDA)-approved medication for gastroparesis. Clinicians may prescribe other medications such as erythromycin and domperidone [
1,
4,
5]. Antiemetic agents are often given for nausea and vomiting. In patients with severe symptoms, surgical intervention may be needed—enteral nutrition, pyloromyotomy, gastric electric stimulation [
4]. A subset of patients suffer from debilitating pain refractory to the above therapies. Medications such as dicyclomine and hyoscamine or symptom modulators such as nortriptyline may be used for the abdominal pain. Despite evidence that opiate narcotics may worsen gastroparesis symptoms, clinicians may resort to the use of opiate pain medications when other modalities do not succeed [
15]. Jehangir et al. found 13% of patients with gastroparesis report the use of opiate medications for abdominal pain in their retrospective review at a large tertiary academic center [
5].
Patients with gastroparesis may need to use opiate medications for non-gastroparesis pain, such as chronic back pain, knee pain, or other musculoskeletal (MSK) conditions that have not responded to conventional modalities of pain control. To date, there has not been a study that compares the quality of life, abdominal pain severity, or gastroparesis symptom severity between patients who use opiates for AP related to gastroparesis and patients using opiates for non-AP reasons.
This study aims to compare the severity of abdominal pain in gastroparesis patients using opiate analgesics for abdominal pain versus those using opiate analgesics for non-abdominal pain, hypothesizing higher pain severity scores in the former group. Additionally, it seeks to measure and compare the morphine equivalent usage, with an expectation of higher usage among patients taking opiates for abdominal pain. Lastly, this study aims to investigate healthcare utilization, hypothesizing that patients using opiates for abdominal pain will have more frequent emergency room visits and hospitalizations compared to those using opiates for non-abdominal pain.
4. Discussion
Abdominal pain (AP) poses significant challenges in the management of patients with gastroparesis, as it is prevalent, difficult to manage, and impacts their quality of life [
2,
13]. This study aimed to assess the medications utilized by gastroparesis patients for AP relief, and explore differences in AP severity between patients primarily using opiate analgesics for AP versus those for musculoskeletal or non-abdominal pain.
In this study, 72% had abdominal pain (AP), with 13% using opiates. This is a lower prevalence of opiate use compared to some previous studies [
5]. Patients using opiate analgesics tended to have lower overall QOL-SF8 scores, indicating a potential negative impact on the quality of life, although the difference was not statistically significant. Notably, individuals utilizing opiates for AP displayed higher average AP severity scores on PAGI-SYM compared to those using opiates for non-AP, along with a higher opiate dosage in morphine equivalents. This suggests challenges in managing AP specific to gastroparesis, especially managing with opiates, advocating against their usage. Prior studies have linked opiate use to heightened AP severity in gastroparesis patients [
2,
5]. This pathologic mechanism is supported by a study which found that patients who used opiates had a significant increase in delayed emptying [
14].
Our study utilized the PAGI-SYM survey for assessing gastroparesis symptoms and the SF8 to evaluate the quality of life in gastroparesis patients. The PAGI-SYM is well established to capture the symptom severity of gastroparesis, dyspepsia, and gastroesophageal reflux disease [
10]. While QOL-SF8 has been found to produce similar results to the more longer SF-36, unlike the SF-36, it has never been tested in gastroparesis patients [
11]. We found that the QOL-SF8 survey, which is short and simple to administer within an office visit’s time constraints, captured nuances even in smaller sample sizes. While the average total scores for QOL-SF-8 were lower for patients reporting opiate use compared to those not using opiates, the QOL scores were not statistically different between patients taking opiates for AP versus those taking them for non-AP.
Patients with gastroparesis taking opiates for AP had more healthcare utilization including emergency room visits and hospitalizations. Those taking opiates for gastroparesis had, on average, 1 emergency room visit and 0.5 hospitalization per 3 months compared to no visits for those taking opiates for non-gastroparesis pain. Patients not taking opiates had 0.88 emergency room visits over 3 months and 0.45 hospital admissions over 3 months. Previous studies have found that among gastroparesis patients, opiate use and marijuana are associated with higher readmission rates [
5,
15,
16]. In one study, patients with severe delay had increased hospitalization and emergency room visits [
14]. Opioid use has been well established to worsen symptoms, often leading to patients seeking hospital treatment for their pain [
5]. A study conducted at the University of Pittsburgh found that 59% of 570 patients who presented to the ED or were admitted to the hospital did so due to abdominal pain [
17]. Taken together, these findings suggest that opioid use exacerbates patients’ symptoms, as reflected in symptom severity scores, and increases their frequency of hospital visits. Further research should explore if those taking opiates for non-gastroparesis abdominal pain have lower readmission and emergency room visit outcomes compared to those taking opiates for gastroparesis abdominal pain.
Given our findings, it is especially important to ensure that patients are abiding by current ACG guidelines [
4]. A low-particulate diet is recommended for patients with gastroparesis [
4]. Currently, metoclopramide is the only FDA-approved medication for treating this condition, although other medications, such as domperidone, are under investigation [
4]. Pyloromyotomy can be considered for refractory cases [
4]. For symptom management, patients often use treatments like acetaminophen, ice, and heating pads, though these have not been extensively studied. It is important to conduct further research on these alternative treatments to reduce the use of opioids. Additionally, clinicians from other specialties should consider alternative pain management strategies for their patients with gastroparesis to minimize opioid use.
Benzodiazepine use was highest among those taking opiates for abdominal pain (62.5%) and lowest for those taking opiates for non-abdominal pain (16.7%). Among those not taking opiates, benzodiazepine use rate was 26.19%. A similar trend was noted for marijuana use. Interestingly a double-blind placebo-controlled study found that twice daily CBD improved vomiting episodes and perceived symptoms but did not statistically improve abdominal pain [
14].
Our study had several limitations, including a small sample size due to the difficulty of recruiting patients who use opiates when guidelines strongly advise against opiate use for gastroparesis. This study was conducted at Temple University Hospital GI motility clinic, which may not represent the broader gastroparesis patient population due to its single-center nature. Only patients who completed the entire survey were included, potentially excluding those with more severe symptoms or cognitive difficulties. Non-English speakers were also excluded, possibly under-representing certain demographic groups. This study relied on patient self-reporting for medication use, pain levels, and quality of life measures, introducing potential recall and social desirability biases. Additionally, patients recorded their treatments, pain management, and hospitalizations/ED visits within three months of the clinic visit, which might not capture the full spectrum of their experiences. The self-reported use of controlled substances like opiates, marijuana, and benzodiazepines could lead to under-reporting due to stigma or fear of judgment. A longer study period should be explored to obtain more patients. Additionally, the higher severity of abdominal pain among opiate users may reflect underlying symptoms leading to opiate prescriptions rather than opiates worsening symptoms.
Future research should aim to address these limitations by including larger and more diverse sample sizes to ensure the findings are more generalizable to the broader gastroparesis patient population. Longer follow-up periods would help capture the full spectrum of patient experiences and outcomes. Additionally, intervention studies comparing opiate alternatives for pain management in gastroparesis patients should be conducted to identify effective treatments that do not carry the risks associated with opiate use. Specifically, research should focus on evaluating non-opioid pain management strategies, such as nerve blocks, antidepressants, anticonvulsants, and non-pharmacologic interventions like cognitive behavioral therapy. These studies should also investigate the impact of these alternative treatments on the quality of life and hospital utilization to provide comprehensive care guidelines for gastroparesis patients.
In conclusion, our findings highlight that patients using opiates for abdominal pain had higher pain severity and healthcare utilization compared to patients not using opiates as well as patients using opiates for reasons other than abdominal pain. These findings underscore the challenges of managing gastroparesis-related AP with opiates as well as the management of other pain disorders in those with gastroparesis.