Predictors of depression outcomes in adults with cancer: A 12 month longitudinal study.

Objectives: The prevalence of depression in patients with cancer ranges from 8% to 24% within the first year of receiving a cancer diagnosis. Identifying predictors of depression outcomes may facilitate tailored or more intensive treatment in patient subgroups with a poorer prognosis for depression improvement. The objective of this study was to determine predictors of depression severity and improvement over 12 months among adults with cancer.

Methods: Longitudinal analysis of data from the Indiana Cancer Pain and Depression trial was performed in 309 patients (n = 309) with cancer-related depression. Depression outcomes were assessed at baseline, 1, 3, 6, and 12 months and included depression severity (Hopkins Symptom Checklist-20) and global improvement (Depression Global Rating of Improvement (DGRI)). Multivariable repeated measures analyses, adjusting for treatment group, baseline depression, and time point, were conducted to determine symptom (pain), demographic, and clinical predictors of depression outcomes over 12 months.

Results: Pain was particularly important, with a clinically meaningful reduction in pain predicting a 12-24% greater odds of depression global improvement. Other factors that independently predicted better depression outcomes over 12 months included female sex, newly-diagnosed or maintainence/disease-free cancer, fewer comorbid medical conditions, and higher socioeconomic status. As expected, the three covariates adjusted for in the model (treatment group, passage of time, and baseline depression severity) also predicted depression outcomes.

Conclusion: Pain as well as several demographic and clinical factors predict depression outcomes over 12 months. These findings may help identify patient subgroups requiring closer monitoring and more intensive or tailored depression treatment. Trial Registration clinicaltrials.gov Identifier: NCT00313573.