Prevalence of undertreatment in cancer pain. A review of published literature

Background: Pain is a major health care problem for patients with cancer: despite the existence of guidelines for cancer pain management, undertreatment is a widespread problem. Pain Management Indexes (PMIs) evaluate the congruence between the patient's reported level of pain and the intensity/strength of the analgesic therapy. Negative scores indicate inadequate prescriptions. Materials and methods: We conducted a Medline search using terms for 'pain management', 'index' or 'measure' to select studies which measured undertreatment in cancer settings. Univariate and multivariate logistic regression identified associations between independent predictors and high prevalence of undertreatment. Results: Among the 44 studies identified, 26 studies used the PMI as proposed by Cleeland. The range of negative PMI varied from 8% to 82% with a weighted mean value of 43%. In multivariate analyses, factors associated with negative PMI were date of publication before 2001, provenance from Europe or Asia and countries with a gross national income per capita <$40 000 per year and a care setting not specific for cancer. Age was not a significant predictor for undertreatment. Conclusion: Nearly one of two patients with cancer pain is undertreated. The percentage is high, but consists of a large variability of undertreatment across studies and settings.