Epidemiologic Burden and Treatment of Chronic Symptomatic Functional Bowel Disorders in the United States: A Nationwide Analysis

Abstract

Background & aims: Functional bowel disorders (FBDs) are the most common gastrointestinal problems managed by physicians. We aimed to assess the burden of chronic symptomatic FBDs on ambulatory care delivery in the United States and evaluate patterns of treatment.

Methods: Data from the National Ambulatory Medical Care Survey were used to estimate annual rates and associated costs of ambulatory visits for symptomatic irritable bowel syndrome, chronic functional abdominal pain, constipation, or diarrhea. The weighted proportion of visits associated with pharmacologic and nonpharmacologic (stress/mental health, exercise, diet counseling) interventions were calculated, and predictors of treatment strategy were evaluated in multivariable multinomial logistic regression.

Results: From 2007-2015, approximately 36.9 million (95% CI, 31.4-42.4) weighted visits in patients of non-federally employed physicians for chronic symptomatic FBDs were sampled. There was an annual weighted average of 2.7 million (95% CI, 2.3-3.2) visits for symptomatic irritable bowel syndrome/chronic abdominal pain, 1.0 million (95% CI, 0.8-1.2) visits for chronic constipation, and 0.7 million (95% CI, 0.5-0.8) visits for chronic diarrhea. Pharmacologic therapies were prescribed in 49.7% (95% CI, 44.7-54.8) of visits compared to nonpharmacologic interventions in 19.8% (95% CI, 16.0-24.2) of visits (P < .001). Combination treatment strategies were more likely to be implemented by primary care physicians and in patients with depression or obesity. The direct annual cost of ambulatory clinic visits alone for chronic symptomatic FBDs is approximately US$358 million (95% CI, 233-482 million).

Conclusions: The management of chronic symptomatic FBDs is associated with considerable health care resource use and cost. There may be an opportunity to improve comprehensive FBD management because fewer than 1 in 5 ambulatory visits include nonpharmacologic treatment strategies.

Keywords: Abdominal Pain; Constipation; Cost; Diarrhea.

Figure 1

Identification of the study population of symptomatic adult patients with a chronic functional bowel disorder. n represents unweighted observations based on direct visit sampling; N represents weighted estimates after applying survey sample weights.

Figure 2

Weighted proportions of pharmacologic and nonpharmacologic interventions in ambulatory outpatient visits for chronic, symptomatic functional bowel disorders. There were insufficient observations to provide reliable estimates of CAM use. NSAID, nonsteroidal anti-inflammatory drug.

Supplementary Figure 1

Average annual rates per 100,000 US population of adult ambulatory clinic visits for chronic, symptomatic FBDs over time (2007–2015). Error bars represent 95% CIs.

Supplementary Figure 2

Weighted proportions of pharmacologic and nonpharmacologic interventions in ambulatory outpatient visits for chronic, symptomatic FBDs over time.

Supplementary Figure 3

Average annual costs for adult ambulatory clinic visits for chronic, symptomatic FBDs over time (2007–2015). Error bars represent 95% CIs. USD, US dollars.