3045 — Effect of Antidepressant Treatment Duration on All-Cause Mortality in Veterans with Cancer
Jones LE (HSR&D Center for Implementing Evidence-Based Practice (CIEBP), Roudebush VAMC, Indianapolis) , Carney Doebbeling C
(Department of Medicine, Indiana University; Regenstrief Institute; Indianapolis)
Depression significantly increases the risk of all-cause mortality in cancer patients. However, it is unknown whether depression treatment or adequacy of depression treatment mediates this finding. The objective of this study is to determine if all-cause mortality is influenced by receipt of depression treatment and adequacy of antidepressant treatment duration in veterans with and without cancer.
Linked clinical, administrative, and pharmacy data (1997-2005) from a Midwestern VA facility were analyzed. Eight groups of subjects were created based on presence/absence of cancer (excluding non-melanoma skin cancer) and a new-episode of depression using ICD-9 diagnostic codes:
(a) no cancer, no depression (reference group);
(b) no cancer, adequately treated depression;
(c) no cancer, inadequately treated depression;
(d) no cancer, depression without treatment
(e) cancer, no depression;
(f) cancer, adequately treated depression;
(g) cancer, inadequately treated depression;
(h) cancer, depression without treatment.
Five cancer sites were defined: prostate, colorectal, lung, hematologic, and “other”. Adequacy of antidepressant treatment duration was evaluated using VA clinical practice guidelines. Adequate duration was defined as an antidepressant medication possession ratio =80% in the guideline-recommended depression treatment period. Cox proportional hazards models were used to calculate adjusted hazard rates for all-cause mortality in each group and by cancer site.
35,920 subjects were available for analysis. 8,619 deaths were documented. Compared to non-depressed subjects without cancer, the adjusted hazard ratios (HRs) for all-cause mortality in each group were significantly increased:
(a): HR=1.00 (reference group);
(b): HR=0.25 (CI95: 0.06-1.00);
(c): HR=1.07 (CI95: 0.99-1.16);
(d): HR=1.65 (CI95: 1.24-2.20);
(e): HR=2.92 (CI95: 2.78-3.07);
(f): HR=1.31 (CI95: 0.33-5.25);
(g): HR=2.52 (CI95: 2.20-2.88);
(h): HR=4.51 (CI95: 3.88-5.23).
HRs were constant across cancer site.
Under-treatment and lack of treatment for depression significantly increase the risk of all-cause mortality in all patients, and is especially predictive of mortality in cancer patients. Depression treatment duration by cancer site had minimal effect on mortality.
Improvement in depression treatment practices could result in increased patient longevity. Under-treatment or lack of depression treatment adversely affects patient outcomes. Future research should prospectively address the effect of adequate depression treatment in cancer patients on mortality and other health outcomes, including adherence to cancer therapies and cancer progression.