Background: The recent Institute of Medicine Report assessing the state of pain care in the United States acknowledged the lack of consistent data to describe the nature and magnitude of unrelieved pain and identify subpopulations with disproportionate burdens.

Objectives: We synthesized 20 years of cumulative evidence on racial/ethnic disparities in analgesic treatment for pain in the United States. Evidence was examined for the 1) magnitude of association between race/ethnicity and analgesic treatment; 2) subgroups at an increased risk; and 3) the effect of moderators (pain type, setting, study quality, and data collection period) on this association.

Methods: United States studies with at least one explicit aim or analysis comparing analgesic treatment for pain between Whites and a minority group were included (SciVerse Scopus database, 1989-2011).

Results: Blacks/African Americans experienced both a higher number and magnitude of disparities than any other group in the analyses. Opioid treatment disparities were ameliorated for Hispanics/Latinos for "traumatic/surgical" pain (P = 0.293) but remained for "non-traumatic/nonsurgical" pain (odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.64-0.77, P = 0.000). For Blacks/African Americans, opioid prescription disparities were present for both types of pain and were starker for "non-traumatic/nonsurgical" pain (OR = 0.66, 95% CI = 0.59-0.75, P = 0.000). In subanalyses, opioid treatment disparities for Blacks/African Americans remained consistent across pain types, settings, study quality, and data collection periods.

Conclusion: Our study quantifies the magnitude of analgesic treatment disparities in subgroups of minorities. The size of the difference was sufficiently large to raise not only normative but quality and safety concerns. The treatment gap does not appear to be closing with time or existing policy initiatives. A concerted strategy is needed to reduce pain care disparities within the larger quality of care initiatives.