Predictors of cancer-related pain improvement over time.

OBJECTIVE: To determine the predictors of pain improvement among patients being treated for cancer-related pain over 12 months.

METHODS: A secondary analysis of the telephone care Indiana Cancer Pain and Depression trial was performed. Patients (n = 274) were interviewed at baseline and after 1, 3, 6, and 12 months. Pain improvement outcomes included both a continuous measure (Brief Pain Inventory score) and a categorical measure (pain improved versus pain not improved). Predictor variables included change in depression, age, sex, race, marital status, socioeconomic disadvantage, medical comorbidity, type of cancer, and phase of cancer. Multivariable repeated measures were conducted, adjusting for intervention group assignment, baseline pain severity, and time in months since baseline assessment.

RESULTS: Factors significantly predicting both continuous and categorical pain improvement included participating in the intervention group (β = -0.92, p < .001, odds ratio [OR] = 2.53, 95% confidence interval [CI] = 1.65-3.89), greater improvement in depression (β = -0.31, p = .003, OR = 1.84, 95% CI = 1.35-2.51), higher socioeconomic status (Socioeconomic Disadvantage index; β = 0.25, p = .034; OR = 0.73, 95% CI = 0.56-0.94), and fewer comorbid conditions (β = 0.20, p = .002; OR = 0.84, 95% CI = 0.73-0.96). Patients with more severe pain at baseline or with recurrent or progressive cancer were less likely to experience continuous or categorical pain improvement, respectively.

CONCLUSIONS: Effective management of depression and comorbid conditions along with improvement of social services could be critical components of a comprehensive pain management. Patients with more severe pain or with recurrent or progressive cancers may require closer monitoring and adequate treatment of pain. Trial Registration clinicaltrials.gov Identifier: NCT00313573.