Patients with cancer are known to have higher rates of depression than the general public—a factor that may reduce adherence to cancer treatment and increase their risk of death. The findings “add to the pressing need to encourage adherence to [antidepressants] among cancer patients,” wrote Gal Shoval, M.D., of the Geha Mental Health Center in Tel Aviv, Israel, and colleagues.
To examine the relationship between antidepressant adherence and mortality in people with cancer, Shoval and colleagues analyzed the medical records of patients with cancer who had at least one prescription for an antidepressant between January 2008 and January 2012. Patients were followed from the time of initial antidepressant prescription until death or the end of the four-year study.
Patients were categorized into one of four adherence groups: Nonadherent if adherence was below 20%, poor adherence for those with 20% to 50% adherence, moderate adherence for those with 50% to 80% adherence, and good adherence for those with adherence above 80%. Of the 42,075 patients included in the analysis, 28.9% were nonadherent, 16.2% had poor adherence, 17.6% had moderate adherence, and 37.4% had good adherence.
The researchers found that greater adherence to antidepressants was associated with decreased risk of all‐cause mortality, after adjusting for age, sex, socioeconomic status, smoking status, and physical comorbidities. Compared with the nonadherent group, risk of death was 20% lower in those with good adherence, 23% lower in those with moderate adherence, and 11% lower in those with poor adherence. A subanalysis of patients with melanoma, breast, colon, lung, or prostate cancer found similar results by cancer type except for melanoma.
The researchers noted several limitations of the study, including the fact they did not have access to causes of death data.
“Our findings not only indicate that adherence to [antidepressants] is associated with increased survival in patients with cancer, but that this relationship may be to some extent continuous, that is, even partial adherence to [antidepressants] may be beneficial in terms of survival,” the authors wrote.
For related information, see the Psychiatric News article “Best Practices for Treating Cancer Patients With Psychiatric Symptoms.”