Association of both depressive symptom scores and specific depressive symptoms with all-cause mortality and cardiovascular mortality among participants with chronic kidney disease

Background Most research has focused on overall depressive symptom scores, potentially overlooking the distinct effects of individual symptoms. This study aims to investigate the association between both depressive symptom scores and specific depressive symptoms with all-cause and cardiovascular disease (CVD) mortality among participants with chronic kidney disease (CKD). Methods 2981 participants with CKD, aged 18 years old, were enrolled from NHANES from 2007 to 2014. Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9). The total PHQ-9 score ranges from 0 to 27, with higher scores indicating greater severity of depressive symptoms. The primary outcomes were all-cause mortality and CVD mortality. Weighted COX regression was used to analyze association of both depressive symptom scores and specific depressive symptoms with all-cause mortality CVD mortality. Results After an average follow-up of 92 months, 932 deaths among 2981 participants with CKD were recorded, of which 332 were CVD deaths. The RCS plot showed a linear relationship between depressive symptom scores and all-cause (nonlinear P -value = 0.346) and CVD mortality (nonlinear P -value = 0.177). After full adjustment for potential confounders, every 1-point increase in depressive symptom score was associated with a 4% and 5.4% increase in all-cause (HR, 1.040; 95% CI, 1.020-1.060; P -value <0.001) and CVD mortality (HR, 1.054; 95% CI, 1.027-1.081; P -value <0.001), respectively. Additionally, 6-items (Uninterested in things, Feeling down, Tiredness, Change of appetite, Change in speed of action, and Suicidal ideation) in the PHQ-9 were independently associated with all-cause mortality. Similarly, 3-items (Uninterested in things, Feeling down, and Tiredness) were significantly associated with CVD mortality. There was no significant interaction between depressive symptom scores and all-cause and CVD mortality in any subgroup (all P -values for interaction > 0.05). Sensitivity analysis also further confirmed the stability of the above results. Conclusions The elevated depressive symptom scores were significantly associated with an increased risk of all-cause and CVD mortality in participants with CKD. Furthermore, 6 specific depressive symptoms were associated with a high risk of all-cause death, and 3 specific depressive symptoms were associated with a high risk of CVD death.