Heartbroken, Sick at Heart, Downhearted — Figures of Speech or Medical Reality?
Heartbroken, Sick at Heart, Downhearted—Figures of Speech or Medical Reality?
Abstract & commentary
Synopsis: This study found the subsequent six-year risk of death was 24% higher in those who were at risk for clinical depression than those who were not at risk.
Source: Schulz R, et al. Arch Intern Med 2000;160:1761-1768.
Measuring and controlling for the most extensive array of sociodemographic and physical health variables ever studied, Schulz and colleagues set out to examine the relationship between baseline depression and death. They extensively evaluated 5201 community-dwelling men and women older than the age of 65 (mean age, 72.8), then followed them for an average of six years. Baseline evaluation included the Center for Epidemiologic Studies Depression Scale (CES-D) and four categories of covariates. Those covariates were sociodemographic factors, prevalent clinical disease, subclinical disease, and biologic and behavioral risk factors. Factors in these covariate categories have previously been shown to be predictors of mortality covariates separately1 and for all of the covariates together.
About 20% of the sample were deemed at risk for clinical depression, based on a CES-D score of 8 or higher. The overall mortality rate over the subsequent six years was 18.9%. In the combined model, controlling for the significant covariates, the following were found to be predictors of mortality: increasing age, male gender, lower educational status, being other than never-married or married, hypertension, congestive heart failure, stroke, intermittent claudication, reduced forced expiratory volume in one second (FEV1), lower ankle-arm ratio, reduced left ventricular ejection fraction, carotid stenosis, glucose intolerance, current (but not past) smoking, a low (but not high) body mass index (BMI), and a CES-D score of 8 or higher. The subsequent six-year risk of death was 24% higher in those who were at risk for clinical depression than those who were not.
Two items of the CES-D were most predictive of mortality. They were: "I felt that everything I did was an effort," and "I could not get going." Schulz et al speculate that decreased emotional vitality or vital exhaustion are linked to functional decline; such individuals may "give up" and disengage from healthy behavior or supportive relationships. They also point out that some of the discrepancy in the literature between studies that find a link between depression and death and those that don’t may be because the latter group tends to rely on self-reported health, but studies that have reported an association have tended to use objective measures of health.
Comment by Barbara Phillips, MD, MSPH
Schulz et al have shown, at least within the limits of our current knowledge, that depression kills. Because the study is prospective and controls for just about every variable currently known to be associated with death, we are on reasonably safe ground to conclude that there is a cause-and-effect relationship. Because cardiovascular disease is the leading cause of death in this country, and because there is some evidence that depression has been linked to cardiovascular death,2 terms like "broken-hearted" and "sick at heart" become more than just fanciful sayings.
I was curious about the CES-D instrument. Schulz promptly faxed me a copy when I e-mailed him. The instructions for administration say to state to the patient/subject: "I am going to read you a list of ways you might have felt or behaved in the last week. After I read an item, please look at this card and tell me how often you have felt this way during the last week."
Each of the 10 questions has the following five possible responses and point scores: rarely or none of the time (< 1 day): 0 pts; some or a little of the time (1 to 2 days): 1 pt; a moderate amount of time (3 to 4 days): 2 pts; most of the time: 3 pts (questions 5 and 8 are reverse scored).
Here are the 10 questions:
1. I was bothered by things that usually don’t bother me.
2. I had trouble keeping my mind on what I was doing.
3. I felt that everything I did was an effort.
4. I felt depressed.
5. I felt hopeful about the future.
6. I felt fearful.
7. My sleep was restless.
8. I was happy.
9. I felt lonely.
10. I could not get going.
The cutoff score for depression on this test was 8. This test has been around for a while,3 and is fairly well-validated.4 When one thinks about these 10 issues in the context of normal aging, it is easy to see why elderly have high levels of depressive symptoms.
A couple of characteristics that did not predict mortality in this study are worth mentioning. Thinness was associated with increased mortality, but obesity was not. When I asked about this, Schulz speculated that "being thin was another illness marker," and I agree. I also speculate that obesity was not a mortality risk factor in this study because these people were 65 and older. There is no question that obesity kills;5 morbidly obese people don’t generally live to be 65 and older, so they did not constitute a big percentage of the participants in this study, whose mean BMI was 25.9. The other interesting negative risk factor was alcohol consumption. As has previously been shown by others,6 light (1-7 drinks/wk) and moderate (> 7 drinks/wk) drinkers had lower mortality (RR 0.82 and 0.75, respectively) than did nondrinkers.
The next logical step, of course, is to prove that people with treated depression have a lower mortality rate than those with untreated depression. I am probably not going to wait for that study before acting on the results of this one.
References
1. Fried LP, et al. JAMA 1998;279:585-592.
2. Anda R, et al. Epidemiology 1993;4:285-294.
3. Radloff LS. Appl Psychol Meas 1977;1:385-401.
4. Andresen EM, et al. Am J Prev Med 1994;10:77-84.
5. Wellborn TA, et al. J Obes Relat Metab Disord 2000; 24:108-115.
6. Gaziano JM, et al. J Am Coll Cardiol 2000;35:96-105.
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