Differences in the Opioid Consumption of Terminally Ill Schizophrenic and Nonschizophrenic Cancer Patients: Analysis of Secondary National Population Data

Abstract

Context: It is uncertain whether terminally ill schizophrenic cancer patients are hypoalgesic or have disparities in pain management.

Objectives: The objective of this study was to analyze the dosage of opioids used in terminally ill cancer patients with and without schizophrenia.

Methods: This is a population-based retrospective cohort study based on data derived from the Taiwan National Health Insurance Research Database. Patients aged >20 years and newly diagnosed between 2000 and 2012 with at least one of the six most common cancers were included. After 1:4 matching, 1001 schizophrenic cancer patients comprised the schizophrenia cohort, while 4004 cancer patients without schizophrenia comprised the nonschizophrenia cohort. The percentage of opioid use, accumulated dose, and average daily dose near the end of life were analyzed for each cohort using multiple logistic and linear regression models.

Results: The percentage of opioid use was lower in the schizophrenic cohort than the nonschizophrenic cohort during the last month before death (69.6% vs. 84.8%, odds ratio = 0.40, 95% CI = 0.34-0.48). The accumulated dose of opioid consumption was also lower in the schizophrenic cohort (2407 mg vs. 3694 mg, P value < 0.05).

Conclusion: Near the end of life, cancer patients with schizophrenia use less opioid than their nonschizophrenic counterparts. Cognitive impairment may be a cause in the disparity in end-of-life care for terminally ill schizophrenic cancer patients. Thus, we should formulate a more accurate pain scale system and pay attention to their need for pain treatment.

Keywords: Schizophrenia; cancer; end-of-life care; opioid.