Burden of illness of opioid-induced constipation among commercially insured patients with cancer in the United States

Opioid-induced constipation (OIC) is a significant adverse effect of opioid use, affecting patients who rely on opioids for pain management.¹ OIC is characterized by infrequent bowel movements, hard stools, and difficulty passing stool, leading to substantial discomfort, impaired daily activity, and reduced quality of life for patients.^1-3 Prior studies have demonstrated significant incremental healthcare costs associated with OIC among opioid users.^4-8 However, there is limited evidence evaluating OIC among continuous opioid users. Additionally, cancer patients often experience pain due to their disease or cancer treatment, leading to higher rates of opioid use and an increased risk of developing OIC.⁹

Purpose/Objectives:

This study aimed to compare the healthcare resource utilization (HRU) and healthcare costs between commercially insured continuous opioid users with OIC and those without OIC in the United States (US), among the population of patients with cancer.

Method:

Commercially insured patients (18-64 years) with ≥90 days continuous opioid use were identified from IQVIA PharMetrics® Plus claims (10/2015-12/2021). Patients were classified into two cohorts (OIC or No OIC) based on presence/absence of an OIC indicator (constipation diagnosis or prescription fill for constipation treatment). For the OIC cohort, the index date was the date of the first OIC indicator within an eligible continuous opioid use episode. In the No OIC cohort, a random index date was selected to match the time from continuous opioid use episode start to the index date in the OIC cohort. Patients with cancer (≥1 diagnosis during the 3-month baseline period) were identified within the two cohorts and entropy-balanced. All-cause HRU was evaluated using incidence rate ratios (IRRs) and odds ratios (ORs). All-cause total healthcare costs were compared using mean differences. Associated 95% confidence intervals (CIs) and p-values were reported for HRU and costs.

Results:

Characteristics were similar between the OIC (N=19,840) and No OIC (N=53,080) cohorts. The OIC cohort incurred significantly higher total healthcare costs versus No OIC (mean difference [95% CI]=$64,430 [60,484-68,376]; p< 0.001). Higher costs among the OIC cohort were driven by differences in both medical (mean difference [95% CI]=$60,961 [57,242-64,681]; p< 0.001) and pharmacy costs (mean difference [95% CI]=$3,469 [2,436-4,501]; p< 0.001). HRU was significantly higher in the OIC than No OIC cohort, with higher odds of outpatient (OR [95% CI]= 3.8 [2.9-4.9]) and emergency room visits (OR [95% CI]= 1.7 [1.6-1.8]), and incidence of inpatient admissions (IRR [95% CI]= 2.0 [1.9-2.1]; all p< 0.001).

Conclusions: In this real-world study of commercially insured US adults with cancer and continuous opioid use, OIC was associated with a significant economic burden. The findings are consistent with prior analyses in US cancer populations,4,6 with a greater economic burden relative to studies in non-cancer populations.5,7,8 This highlights the heightened challenges faced by cancer patients who require continuous opioid treatment. It also emphasizes the need for tailored interventions to address OIC in vulnerable populations.

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