Study of trends in opioid prescription for chronic abdominal pain from 2009-2014 using National Ambulatory Medical Care Survey (NAMCS) data




Adams, Ann
Dodgen, Leilani
Aryal, Subhash
Maack Rangel, Jessica


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Purpose: Chronic abdominal pain (CAP) is a common reason for health care visits affecting approximately 25% of adults. Often opioids are prescribed to treat CAP, though there is not much evidence to support this. Opioid use has been connected to increased morbidity and mortality of patients including drug misuse, abuse and exacerbation of abdominal pain. The purpose of this study is to examine national trends in prescriptions of opioids for treating CAP using National Ambulatory Medical Care Survey (NAMCS). Methods: NAMCS data were retrieved from the National Center for Health Care Statistics (2009-2014). The original data were paired into two-year groupings. We conducted stratified analysis and combined analysis for each 2-year period. We categorized patient diagnoses via the clinical classification software (CCS). Patient data were included if they were 18 or older and the reason for visit was CAP (including: Stomach pain, cramps, spasms, generalized lower or upper abdominal pain, and liver, gallbladder, or biliary tract pain). Certain types of abdominal pain were excluded including: pain from injury, infectious/parasitic diseases, neoplasms, diseases of the genitourinary system and pregnancy/childbirth complications. Logistic regression was used to determine trends in the number of visits where opioids were prescribed, and factors related to opioid prescriptions. Results: Visits for 2009-2010, 2011-2012, 2013-2014 were 10.3 million, 9.7 million and 10.2 million respectively. During the same time periods the estimated number of opioid prescriptions for treating CAP were 300 thousand, 400 thousand and 100 thousand respectively. There were no significant differences in the number of opioid prescriptions between time periods (p [greater than] 0.05). Conclusions: Even though an increasing trend for opioid prescriptions was reported in the literature for treating abdominal pain for 1997-1999 (7.9% increase) and 2006-2008 (15.5% increase), this analysis revealed the opioid prescription rate during this study period was not statistically different from year to year. Further analyses will incorporate additional data from the National Hospital Ambulatory Medical Care Survey (collected with NAMCS) which only contains hospital outpatient visits. This will contribute to a more robust, evidence-based analysis about practices in opioid prescribing, and inform the work of clinicians and public health officials working to address the US opioid epidemic today.