Research ArticleOriginal Research

Depression and Increased Mortality in Diabetes: Unexpected Causes of Death

Elizabeth H. B. Lin, Susan R. Heckbert, Carolyn M. Rutter, Wayne J. Katon, Paul Ciechanowski, Evette J. Ludman, Malia Oliver, Bessie A. Young, David K. McCulloch and Michael Von Korff
The Annals of Family Medicine September 2009, 7 (5) 414-421; DOI: https://doi.org/10.1370/afm.998

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Tables

  • Table 1.

    Baseline Clinical and Demographic Characteristics by Depression

    VariableTotalNo DepressionMinor DepressionMajor Depression
    aMedical comorbidity, excluding comorbidity associated with diabetes and depression.
    Number4,1843,334 (79.7)357 (8.5)493 (11.8)
    Age, mean (SD), years64.0 (12.5)64.7 (12.2)64.5 (13.2)59.6 (12.8)
    Female, n (%)2,030 (48.5)1,564 (46.9)180 (50.4)286 (58.0)
    Nonwhite, n (%)879 (21.0)679 (20.4)95 (26.6)105 (21.3)
    High school or less, n (%)1,057 (25.3)808 (24.2)113 (31.7)136 (27.6)
    Marital status single, n (%)1,390 (33.2)1,060 (31.8)127 (35.6)203 (41.2)
    Diabetes duration, mean (SD), years8.6 (8.2)8.5 (8.2)10.0 (9.0)8.8 (7.3)
    HbA1C, mean (SD), %7.8 (1.5)7.7 (1.5)7.9 (1.6)8.1 (1.7)
    Treatment, n (%)
        None or diet1,078 (25.8)913 (27.4)80 (22.4)85 (17.2)
        Hypoglycemic only1,971 (47.1)1,607 (48.2)161 (45.1)203 (41.2)
        Any insulin1,135 (27.1)814 (24.4)116 (32.5)205 (41.6)
    Hypertension, n (%)2,565 (61.3)2,029 (60.9)231 (64.7)305 (61.9)
    Body mass index, mean (SD)31.7 (7.2)31.2 (6.7)32.3 (7.0)35.0 (9.1)
    Physical activity 1 d/wk or more, n (%)1,362 (32.6)969 (29.1)159 (44.5)234 (47.5)
    Current smoking, n (%)362 (8.7)246 (7.4)38 (10.6)78 (15.8)
    RXRiska3,132 (2403)3,049 (2297)3,383 (2472)3,508 (2944)
  • Table 2.

    Cause-Specific Mortality

    Cause of DeathNo.%
    CNS=central nervous system.
    Atherosclerotic cardiovascular disease24842.7
        Coronary disease20234.8
        Ischemic stroke356.0
        Peripheral vascular disease111.9
    Cancer15626.9
        Lung325.5
        Colorectal172.9
        Prostate122.1
        Breast122.1
        Other and unknown primary site8314.3
    Noncardiovascular, noncancer17730.5
        Infection447.6
        Dementia and other CNS disease335.7
        Renal failure172.9
        Chronic obstructive pulmonary disease and other respiratory disease274.6
        Cirrhosis and other gastrointestinal disease183.1
        Hemorrhagic stroke81.4
        Cardiac, noncoronary81.4
        Accident50.9
        Suicide40.7
        Other132.2
    Total581100.0
  • Table 3.

    Hazard Ratios for All-Cause Mortality, Cardiovascular Mortality, Cancer Mortality, and Noncardiovascular, Noncancer Mortality in Patients with Diabetes, by Depressive State

    Cause of Death
    Baseline and Adjusted ModelsAll-CauseCardiovascularCancerNoncardiovascular, Noncancer
    CI=confidence interval; CVD = cardiovascular disease; HR = hazards ratio.
    aDemographic characteristics at baseline: age, sex, race, education, and marital status.
    bClinical characteristics at baseline: diabetes duration, treatment intensity, medical comorbidity (excluding diabetes, depression), and hypertension diagnosis.
    cHealth behaviors and disease control measures at baseline: body mass index, smoking, limited physical activity, and glycated hemoglobin.
    Events, No. (%)
        Not depressed428 (12.8)187 (5.6)123 (3.7)118 (3.5)
        Minor depression65 (18.2)29 (8.1)13 (3.6)23 (6.4)
        Major depression88 (17.8)32 (6.5)20 (4.1)36 (7.3)
    Adjusted for demographic characteristics,a HR (95% CI)
        Minor depression1.48 (1.14–1.93)1.51 (1.02–2.24)1.04 (0.59–1.85)1.87 (1.19–2.93)
        Major depression2.26 (1.79–2.85)2.00 (1.37–2.94)1.61 (0.99–2.59)3.35 (2.30–4.89)
    Adjusted for demographica and clinical characteristics,b HR (95% CI)
        Minor depression1.29 (0.99–1.68)1.27 (0.86–1.89)0.99 (0.56–1.76)1.59 (1.01–2.49)
        Major depression1.62 (1.28–2.06)1.35 (0.91–1.99)1.36 (0.83–2.22)2.26 (1.52–3.35)
    Adjusted for demographic,a clinical characteristics,b health habits and disease control measures,c HR (95% CI)
        Minor depression1.24 (0.95–1.61)1.20 (0.81–1.78)0.94 (0.53–1.68)1.54 (0.98–2.42)
        Major depression1.52 (1.19–1.95)1.25 (0.83–1.86)1.27 (0.77–2.10)2.15 (1.43–3.24)

Additional Files

  • The Article in Brief

    Depression and Increased Mortality in Diabetes: Unexpected Causes of Death

    Elizabeth H. B. Lin , and colleagues

    Background Previous research has found that people with diabetes are more likely than others to experience depression, and that people with both diabetes and depression have higher rates of death than diabetes patients with no depression. This study examined whether depression in diabetes patients was associated mainly with death from cardiovascular disease (the focus of most research on depression and mortality since the two were first linked), or whether it was also associated with increased risks of death from other common medical causes.

    What This Study Found Patients with both diabetes and depression face substantially higher risks of death beyond cardiovascular-related death.

    Implications

    • Obesity, smoking, and physical inactivity are more common among patients with diabetes and depression compared with diabetes patients without depression, and may help explain the association of depression with a wide range of causes of death. Other factors contributing to higher death rates could include not taking medicines as prescribed and physiologic changes.
    • Future research on patients with diabetes and depression should aim to improve health behavior, medication adherence, and control of other medical conditions, in addition to ensuring optimal depression care.
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