Individual and Joint Associations of Depression‐Related Symptoms and Sleep Quality With Overall Survival Among Patients With Ovarian Cancer: Evidence From a Prospective Cohort Study

Background: As the evidence linking depression and sleep quality to overall survival (OS) is lacking, we aim to evaluate the individual and joint associations of depression‐related symptoms and sleep quality with OS among patients with ovarian cancer (OC). Method: A total of 554 patients with OC were included. Depression‐related symptoms and sleep quality were measured using the Patient Health Questionnaire (PHQ‐9) and the Pittsburgh Sleep Quality Index (PSQI). The primary analysis utilized the average levels of depression‐related symptoms and sleep quality by averages of PSQI score and PHQ score between pre‐diagnosis and post‐diagnosis. Deaths were ascertained until February 16, 2023, via medical records and active follow‐up. Cox proportional hazard regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the joint and individual associations of sleep quality and depression‐related symptoms with OC survival. Result: A total of 205 deaths occurred during a median follow‐up of 44.6 months. The average level of depression‐related symptoms and sleep quality were independently associated with OS (HR depression vs. no depression = 1.55, 95% CI = 1.10–2.17; HR poor sleep vs. good sleep = 2.05, 95% CI = 1.51–2.75). We documented multiplicative and additive interactions between these two factors in relation to OS ( P interaction < 0.01; relative excess risk due to interaction = 0.16, 95% CI = 0.01–0.31). Combinations of depression‐related symptoms and poor sleep quality were positively associated with OC mortality (HR = 2.61, 95% CI = 1.70–4.00), compared to patients with good sleep quality and without depression‐related symptoms. Conclusion: Poor OC survival was observed among patients with poor sleep quality and depression‐related symptoms, independently and jointly.