Can you provide a brief overview of the importance of assessing risk factors associated with the development of OIC?

Although opioids are effective therapies to relieve pain, they are associated not only with dangerous side effects but also many bothersome ones, including constipation, nausea, and vomiting (among others). According to published data, between 40% and 90% of patients taking opioids have constipation and other gastrointestinal (GI) side effects that can adversely affect adherence to pain medication regimens and quality of life.

Unlike other opioid-related adverse effects, OIC is not dose-dependent and does not resolve over time. When patients are prescribed opioids, clinicians must recognize the potential risk factors for developing OIC, including older age and female gender. When taken in context with other patient factors, such as types of concomitant medications, this information can help to determine the risks and causes for developing OIC. It’s also critical to have a firm grasp of the patient’s medical issues and why they are receiving opioids. Surprisingly, the type and strength of opioid used do not significantly influence the manifestation of OIC. For example, bowel dysfunction is one of the most common and bothersome side effects associated with all opioid molecules.

What tools are recommended for diagnosing OIC?

OIC is often underdiagnosed, and complaints regarding symptoms may vary from patient to patient. The Rome diagnostic criteria are expert consensus criteria for diagnosing functional gastrointestinal disorders, including OIC. The current version, Rome IV, was released in 2016 after Rome III had been in effect for a decade, but few changes were made to the criteria defining OIC in this update (Table 1).1

Guidelines recommend that patients be asked about their bowel habits prior to starting opioids to help determine what percentage of their symptoms may be related to opioids. They should be asked about their stool consistency, size, and frequency of movements, as well as the degree of straining and their sense (if any) of incomplete evacuation. The Bristol Stool Form Scale (BSFS) is a helpful tool to get patients to describe their stool form and consistency (Table 2).2 In addition to using the Rome IV criteria and BSFS, clinicians should take a complete medication and vitamin/supplement history because many of these agents can contribute to constipation. Documentation of laxative use and frequency should be noted in medical records. If opioids are not suspected, clinicians should develop work-ups or refer patients in an attempt to diagnose other causes of GI dysfunction.

What tools can clinicians use to foster communication with patients on the impact of OIC?

The most efficient and cost-effective way to assess OIC symptoms is to have open conversations with patients, even though many will avoid these discussions or be too embarrassed to speak about their bowel patterns with clinicians. Patient complaints regarding constipation may vary significantly from one individual to the next. Some may report that they are not constipated, but the reality is they are suffering from problems associated with OIC, such as those listed in Table 1.

The American Chronic Pain Association has issued the Opioid Induced Constipation Conversation Guide, a tool that provides a foundation for opening dialogue between patients and their clinicians.3 Using a visual representation of a patient’s condition, this informal guide walks patients through a series of questions about lifestyle, intestinal discomfort, regularity, and personal choices about diet and fluid intake. This information can be used to steer conversations with patients about their OIC symptoms.

Several formal assessment tools have been developed in clinical trials for various laxative agents, including those approved for OIC. These aids can be administered by clinicians and may provide both objective and patient-reported measures (Table 3).4-9 Objective outcomes that can be measured in clinical trials include frequency of bowel movements (BMs), time to BM (laxation) from intervention, transit time, and stool consistency. Patient-reported outcome assessment tools include the Patient Assessment of Constipation-Symptoms (PAC-SYM), Bowel Function Index (BFI), and Bowel Function Diary (BF-Diary), among others. The utility of these tools varies depending on each patient’s unique characteristics.

Why is it important for clinicians to use assessment tools as support in their efforts to communicate more freely with patients about OIC?

Assessing patients for constipation is important in clinical practice because it effects quality of life, healthcare expenditures, and even the quality of pain management that patients achieve. Many patients suffer in silence, so clinicians need to proactively ask about bowel function in every patient who is prescribed an opioid. Several valuable tools are readily accessible to diagnose OIC and may help steer conversations with individuals about their symptoms, but these resources are pointless if they aren’t used appropriately. Clinicians must take the lead and promote a dialogue with patients about their symptoms using validated tools that formally assess OIC. These discussions can help us direct patients to newer and potentially more effective treatments that will significantly improve their quality of life.

References

1. Simren M, Palsson OS, Whitehead WE. Update on Rome IV Criteria for colorectal disorders: implications for clinical practice. Curr Gastroenterol Rep. 2017;19:15. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378729/.
2. Lewis SJ, Heaton KW. Stool form scale as a useful guide to intestinal transit time. Scand J Gastroenterol. 1997;32:920-924. Available at: https://www.tandfonline.com/doi/abs/10.3109/00365529709011203.
3. American Chronic Pain Association. Opioid induced constipation conversation guide. 2014. Available at: https://www.theacpa.org/wp-content/uploads/2017/08/ACPA-Opioid_Constipation_Chart-V4.pdf.
4. Gaertner J, Siemens W, Camilleri M, et al. Definitions and outcome measures of clinical trials regarding opioid-induced constipation: a systematic review. J Clin Gastroenterol. 2015;49:9-16. Available at: https://www.ncbi.nlm.nih.gov/pubmed/25356996.
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7. Dubois D, Gilet H, Viala-Danten M, Tack J. Psychometric performance and clinical meaningfulness of the Patient Assessment of Constipation-Quality of Life questionnaire in prucalopride (RESOLOR) trials for chronic constipation. Neurogastroenterol Motil. 2010;22:e54-63. Available at: https://www.ncbi.nlm.nih.gov/pubmed/19761492/.
8. Rentz AM, Yu R, Müller-Lissner S, Leyendecker P. Validation of the Bowel Function Index to detect clinically meaningful changes in opioid-induced constipation. J Med Econ. 2009;12:371-383. Available at: https://www.ncbi.nlm.nih.gov/pubmed/19912069.
9. Camilleri M, Rothman M, Ho KF, Etropolski M. Validation of a bowel function diary for assessing opioid-induced constipation. Am J Gastroenterol. 2011;106:497-506. Available at: https://www.ncbi.nlm.nih.gov/pubmed/21063394.