Prognosis of depression in old age

Differential mortality rates in major and subthreshold depression: meta-analysis of studies that measured both

BACKGROUND

Although the association between depression and excess mortality has been well established, it is not clear whether this is greater in major depression than in subthreshold depression.

AIMS

To compare excess mortality in major depression with that in subthreshold depression.

METHOD

We searched bibliographic databases and included prospective studies in which both major and subthreshold depression were examined at baseline and mortality was measured at follow-up.

RESULTS

A total of 22 studies were included. People with major depression had a somewhat increased chance of dying earlier than people with subthreshold depression but this difference was not significant, although there was a trend (relative risk 1.13, 95% CI 0.98-1.30, P = 0.1). The population attributable fraction was 7% for major depression and an additional 7% for subthreshold depression.

CONCLUSIONS

Although excess mortality may be somewhat higher in major than in subthreshold depression, the difference is small and the overall impact on excess mortality is comparable.

Positive life orientation predicts good survival prognosis in old age

The purpose of this study is to investigate the value of life orientation as a screening tool and survival indicator in old age. A postal questionnaire answered by 2490 random older people (>75 years) included six questions concerning satisfaction with life, feeling needed, plans for future, zest for life, lack of feelings of depression and loneliness. The vital status was followed for 57 months. All-cause mortality rate was 19.1% and 30.3% among elderly with (22%) and without (78%) positive life orientation, respectively (p<0.001). The difference in mortality increased over time. After controlling for age, gender, and subjective health, the protective value of positive life orientation remained significant (hazard ratio, HR=0.78, 95%CI=0.63-0.98, p<0.03). Feeling needed was the strongest independent predictor (HR=0.72, p<0.001). A six-question life orientation identifies old people at risk. Positive life orientation predicts good survival prognosis independently of subjective health.

Positive life orientation as a predictor of 10-year outcome in an aged population

OBJECTIVE

It is well known that depression predicts mortality in old age. However, little is known about the impact of positive emotions. We investigated the impact of positive life orientation on mortality and permanent institutional care in aged birth cohorts.

STUDY DESIGN AND SETTING

Participants (born 1904, 1909, and 1914) underwent detailed assessments with follow-up at 5 and at 10 years. Positive life orientation was determined as answering "yes" to all the following items: being satisfied with life, having zest for life, having plans for the future, feeling needed, seldom feeling lonely or depressed.

RESULTS

Of participants, 102 (20.8%) had a positive life orientation. After 10 years, 54.5% of them were alive, whereas in the rest of the sample 39.5% survived (P=.004). After controlling for age, gender, and health measures, the impact of positive life orientation was still significant (HR=0.89, 95% CI 0.83-0.93). At 5 years, only 2.9% of those having a positive life orientation but 17.5% of the rest of the sample were in permanent institutional care (P=0.003), with a positive life orientation remaining a significant protector against institutional care (OR 0.58, 95% CI 0.36-0.93).

CONCLUSION

Positive attitudes have a long-standing impact on prognosis in old age.

Excess mortality in depression: a meta-analysis of community studies

BACKGROUND

Although most studies examining the relationship between depression and mortality indicate that there is excess mortality in depressed subjects, this is not confirmed in all studies. Furthermore, it has been hypothesized that mortality rates in depressed men are higher than in depressed women. Finally, it is not clear if the increased mortality rates exist only in major depression or also in subclinical depression.

METHODS

A meta-analysis was conducted to examine these questions. A total of 25 studies with 106,628 subjects, of whom 6416 were depressed, were examined. Both univariate and multivariate analyses were conducted.

RESULTS

The overall relative risk (RR) of dying in depressed subjects was 1.81 (95% CI: 1.58-2.07) compared to non-depressed subjects. No major differences were found between men and women, although the RR was somewhat larger in men. The RR in subclinical depression was no smaller than the RR in clinical depression.

LIMITATIONS

Only RRs of mortality were examined, which were not corrected for important confounding variables, such as chronic illnesses, or life-style. In the selected studies important differences existed between study characteristics and populations. The number of comparisons was relatively small.

CONCLUSIONS

There is an increased risk of mortality in depression. An important finding of this study is that the increased risk not only exists in major depression, but also in subclinical forms of depression. In many cases, depression should be considered as a life-threatening disorder.

Depression, depressive symptoms and mortality in persons aged 65 and over living in the community: a systematic review of the literature

BACKGROUND

No recent attempt has been made to synthesize information on mortality and depression despite the theoretical and practical interest in the topic. Our objective was to estimate in the older population the influence on mortality of depression and depressive symptoms.

METHODS

Data sources were: Medline, Embase, personal files and colleagues' records. Studies were considered if they included a majority of persons aged > or = 65 years at baseline either drawn from a total community sample or drawn from a random sample from the community. Samples from healthcare facilities were excluded. Effect sizes were extracted from the papers; if they were not included in the published papers, effect sizes were calculated if possible. No attempt was made to contact authors for missing data.

RESULTS

We found 21 reports on 23 cohorts using depression diagnosis. For 15 of these, odds ratios were pooled using the Greenland method based on confidence intervals (CIs), giving an estimated odds ratio for mortality with depression of 1.73 (95% CI 1.53 to 1.95). A fixed effects meta-regression of these studies suggested that longer follow-up predicted smaller effect sizes (log odds ratios -0.096 per year (95% CI -0.179 to -0.014)). There is a weak suggestion of a reduced effect of depression on mortality for women. We were unable to pool effect sizes from the 17 studies using symptom totals and scales, or from eight studies of specific symptoms.

CONCLUSIONS

The studies show that diagnosed depression in community-resident older people is associated with increased mortality. The picture for sex differences is still unclear.