Gastroparesis is a chronic medical condition characterized by delayed gastric emptying, meaning the stomach struggles to pass its contents into the small intestine. The name, derived from “gastro” (stomach) and “paresis” (partial paralysis), describes the underlying problem of ineffective stomach muscle contractions. Obtaining a single, precise figure for its universal prevalence remains challenging, and the true number of people affected is likely much higher than official reports suggest due to a variety of diagnostic and reporting issues.
Defining Gastroparesis
Gastroparesis is characterized by delayed gastric emptying without any physical blockage in the stomach or small intestine. The stomach muscles, which normally contract to grind food and propel it forward, are not functioning correctly. This dysfunction is often due to damage to the vagus nerve, which regulates the digestive tract’s movements.
The resulting delay leads to a constellation of uncomfortable symptoms. Common complaints include nausea, vomiting, and early satiety (feeling full after eating little food). Patients also frequently experience bloating, abdominal pain, and sometimes significant weight loss. These symptoms can range from mild to severe, greatly diminishing a person’s quality of life.
Quantifying the Condition
Quantifying the exact number of individuals with gastroparesis is difficult because diagnostic practices vary widely, but existing population-based studies offer some estimates. A well-cited study from Olmsted County, Minnesota, estimated the prevalence of “definite” gastroparesis at 24.2 per 100,000 persons in the general population. This figure represents cases confirmed by the gold-standard diagnostic test.
The incidence, or the rate of new cases each year, was estimated in the same study at 6.3 per 100,000 person-years. Other studies using large health insurance databases have reported much higher prevalence figures, sometimes reaching 267.7 per 100,000 adults in the United States. This wide range highlights the difference between carefully diagnosed, community-based figures and those derived from administrative data. Estimates that include patients reporting gastroparesis-like symptoms, even without full diagnostic confirmation, suggest the number of affected individuals could be as high as 1.8% of the population. This larger figure suggests that a substantial number of individuals may have the condition but remain undiagnosed.
Factors Affecting Prevalence Data
The inconsistency in prevalence figures stems from several systemic issues that prevent accurate counting of affected individuals. Many cases are likely overlooked because the symptoms are non-specific and overlap considerably with other common gastrointestinal disorders, such as functional dyspepsia. This overlap often leads to misdiagnosis, where patients presenting with gastroparesis symptoms are instead labeled with a different digestive issue.
Gathering reliable data is also hampered by the diagnostic process. The gold standard test for gastroparesis is the 4-hour gastric emptying scintigraphy with a solid meal. This procedure is time-consuming, costly, and not universally accessible, limiting its use as a widespread screening tool. Studies indicate that a large percentage of patients who receive a clinical diagnosis of gastroparesis have not undergone the necessary objective testing to confirm delayed gastric emptying.
High-Risk Populations
While gastroparesis affects the general population, its prevalence is notably concentrated in several high-risk groups. The most common causes are:
- Diabetic gastroparesis: Poorly controlled diabetes can damage the vagus nerve, leading to delayed emptying in a large percentage of patients with Type 1 and Type 2 diabetes.
- Idiopathic gastroparesis: Cases where no underlying cause can be identified, accounting for a large percentage of patients in many studies.
- Post-surgical gastroparesis: Often results from injury to the vagus nerve during operations on the stomach or esophagus.
- Medication use: Certain drugs, such as opioid pain relievers, are increasingly recognized as contributing factors.
A striking disparity is observed in the condition’s distribution across sexes, as gastroparesis is significantly more common in women than in men. Women are reported to have an incidence rate up to four times higher than men and comprise the majority of patients in both diabetic and idiopathic subgroups. The reasons for this gender difference are not fully understood, but potential factors include the influence of sex hormones on gastric motility.