The baseline characteristics of participants and nonparticipants, such as sex, race, CKD stage, presence of diabetes, and prior depression diagnosis were similar. However, mean (SD) age was 64.5 (12.0) years among participants and 68.8 (11.0) years among nonparticipants (P=.001; 95% CI for the difference, −6.9 to −1.8 years). Two patients in this VA cohort were women and more than half of the patients were white. About half of the patients had diabetes and a fourth had a prior depression diagnosis. Among participants, the prevalences were 6.4% for CKD stage 2, 37.8% for stage 3, 41.2% for stage 4, and 14.6% for predialysis stage 5. Nonparticipants had similar prevalences for the CKD stages.
Of 267 participants, 56 had a current MDE (21%; 95% CI, 3% to 31%) and 211 did not (). The MDE group was younger based on a mean (SD) age of 60.6 (11.9) years compared with the group without an MDE (mean [SD], 65.4 [11.8] years; P = .007; 95% CI for the difference, −8.3 to −1.3 years). There were no significant between-group differences in regard to race, educational level, or marital status. Patients with an MDE, however, were two-thirds less likely to be employed as those without an MDE. The median number of medical comorbidities was 4.0 (inter-quartile range, 2.0 to 5.0) among those with an MDE and 3.0 (inter-quartile range, 2.0 to 4.0) among those without an MDE. Diabetes mellitus was significantly more prevalent among those with an MDE (69.6%) compared with those without an MDE (51.9%; P=.02; 95% CI for the difference, 4% to 32%). More patients with an MDE had histories of drug or alcohol abuse and concurrent psychiatric disorders. Sixty-six percent of those with an MDE had prior depression vs 13.6% of those without an MDE (95% CI for the difference, 39% to 66%; P < .001); and 50.0% with an MDE vs 11.9% without an MDE were taking antidepressant medications (95% CI for the difference, 24% to 52%; P < .001). Twenty-three of 56 patients (41%) agreed to have a new antidepressant prescribed or the dose of their current antidepressant increased at the time of MDE diagnosis (defined as new treatment).
Baseline Characteristics by Depression Statusa
The only difference between groups for laboratory values was for mean (SD) serum phosphorus level, which was higher in those with an MDE (4.2 [1.1]) compared with those without an MDE (3.9 [1.0]) (P=.04; 95% CI for the difference, 0.02 to 0.63; ). There was not a difference between groups in the proportion of patients by CKD stage.
During the 12-month observation period, 127 patients had at least 1 composite event (death, hospitalization, or maintenance dialysis initiation). More patients with an MDE had at least 1 event (60.7%) compared with those without an MDE (44.1%) (P = .03; 95% CI for the difference, 2%–31%; ). The mean (SD) time to the composite event was 260.2 (8.1) days (95% CI, 259.2–261.2 days) overall, and was shorter for those with an MDE (206.5 [19.8] days; 95% CI, 167.7–245.3 days) compared with those without an MDE (273.3 [8.5] days; 95% CI, 256.6–290.0 days) (log-rank P =.003; ). Four patients were excluded from the survival analysis because the date for the first event (hospitalization in each of these cases) was missing. Of the 4 patients, 1 had an MDE and 3 did not have an MDE.
Survival Curves for Outcome Measures
Those with an MDE had a higher risk of death, hospitalization, or maintenance dialysis initiation within 12 months of MDE diagnosis compared with those without an MDE (hazard ratio [HR], 1.82 [95% CI, 1.22–2.71]; ). Variables associated with the composite event in univariate analyses included younger age, white race, higher CKD stage, medical comorbidity, diabetes mellitus, drug or alcohol abuse, lower serum albumin and hemoglobin levels, and higher serum phosphorus levels (data not shown). After adjusting for these covariates, the adjusted HR for the composite outcome was not diminished and remained significant (1.86 [95% CI, 1.23–2.84]; ). Inclusion of new treatment for an MDE was not significantly associated with the composite outcome in the adjusted model (HR, 1.05 [95% CI, 0.48–2.30]; P=.90), and it did not significantly change the hazard of an MDE for the composite outcome (adjusted HR, 1.84; 95% CI, 1.14–2.96).
Adjusted Risks of Events Associated With Major Depressive Episode
One hundred sixteen were hospitalized, 38 initiated maintenance dialysis, and 18 died (). More patients with an MDE compared with those without an MDE were hospitalized (55.4% vs 40.3%, respectively, P=.04; [95% CI for the difference, 0.5% to 29.7%]), but no statistically significant differences in reasons for hospitalization could be observed (). More patients with an MDE were initiated on maintenance dialysis compared with those without an MDE (26.8% vs 10.9%, respectively, P=.003; [95% CI for the difference, 3.6% to 28.2%]; ). Death occurred in 8.9% of those with an MDE and in 6.2% of those without an MDE, but this difference was not statistically significant (95% CI for the difference, −5.4% to 10.8%) ().
Patients with CKD and an MDE had almost twice the risk of being hospitalized (HR, 1.85; 95% CI, 1.22–2.81), and 3 times the risk of initiating dialysis within 1 year (HR, 3.12 [95% CI, 1.62–6.01]; ). After controlling for demographic and clinical variables, the association of having an MDE with both hospitalization (HR, 1.90; 95% CI, 1.23–2.90) and dialysis initiation (HR, 3.51; 95% CI, 1.77–6.97) remained significant (). The HR of death for patients with an MDE was 1.53 (95% CI, 0.55–4.30).