The association between depression and mortality - a comparison of survey- and register-based measures of depression.

BACKGROUND: A number of studies have associated depression with a high mortality risk. However, in surveys, depression is often measured by self-reports in selected sub-samples, while register studies have been based on hospital diagnosis or purchase of antidepressants. We examined how different survey- and register-based measures of depression were associated with 7-year mortality in a cohort of middle-aged Danish men. METHODS: The study was based on 10,517 men born in 1953. Depression was assessed through hospital diagnosis for the period from 1969 to 2004 and by self-reported information on depression, use of antidepressants and the Major Depression Inventory (MDI) from a survey in 2004, in which 58.8% (n=6292) of the men participated. Information on mortality and cause of death was retrieved from registers for the period between 2004 and 2011. RESULTS: Depression diagnosis from hospital registers as well as self-reported depression, use of antidepressants and having a high MDI-score were significantly associated with mortality from all, natural and unnatural causes. The associations were of a similar magnitude for the register-based measure of depression and for the survey-based measures reflecting past depression, but the strongest association was found for current depression as assessed by the MDI-score. LIMITATIONS: The study population consists almost exclusively of white men and the findings may not be generalizable to female populations or other races and ethnicities. CONCLUSIONS: Physicians should be aware of male patients with a history of depression from hospital records or self-reported as they have higher mortality risk years after their first symptom.

Incidence of Depression After Stroke, and Associated Risk Factors and Mortality Outcomes, in a Large Cohort of Danish Patients.

IMPORTANCE: More than 30 million people live with a stroke diagnosis worldwide. Depression after stroke is frequent, and greater knowledge of associated risk factors and outcomes is needed to understand the etiology and implications of this disabling complication. OBJECTIVES: To examine whether the incidence of and risk factors for depression differ between patients with stroke and a reference population without stroke and to assess how depression influences mortality. DESIGN, SETTING, AND PARTICIPANTS: Register-based cohort study in Denmark. Participants were all individuals 15 years or older with a first-time hospitalization for stroke between January 1, 2001, and December 31, 2011 (n = 157 243), and a reference population (n = 160 236) matched on age, sex, and municipality. The data were analyzed between January and March 2016. MAIN OUTCOMES AND MEASURES: The incidence of depression and mortality outcomes of depression (defined by hospital discharge diagnoses or antidepressant medication use) were examined using Cox proportional hazards regression analyses. RESULTS: In total, 34 346 patients (25.4%) with stroke and 11 330 (7.8%) in the reference population experienced depression within 2 years after study entry. Compared with the reference population, patients with stroke had a higher incidence of depression during the first 3 months after hospitalization (hazard ratio for stroke vs the reference population, 8.99; 95% CI, 8.61-9.39), which declined during the second year of follow-up (hazard ratio for stroke vs the reference population, 1.93; 95% CI, 1.85-2.08). Significant risk factors for depression for patients with stroke and the reference population included older age, female sex, single cohabitation status, basic educational attainment, diabetes, high level of somatic comorbidity, history of depression, and stroke severity (in patients with stroke). The associations were strongest for the reference population. In both populations, depressed individuals, especially those with new onset, had increased all-cause mortality (hazard ratio for new-onset depression, 1.89 [95% CI, 1.83-1.95] for patients with stroke and 3.75 [95% CI, 3.51-4.00] for the reference population) after adjustment for confounders. Similar patterns were found for natural and unnatural causes of death. In most models, the depression-related relative mortality was approximately twice as high in the reference population vs the stroke population. CONCLUSIONS AND RELEVANCE: Depression is common in patients with stroke during the first year after diagnosis, and those with prior depression or severe stroke are especially at risk. Because a large number of deaths can be attributable to depression after stroke, clinicians should be aware of this risk.

Depression following acute coronary syndrome: a Danish nationwide study of potential risk factors.

PURPOSE: Depression is common following acute coronary syndrome, and thus, it is important to provide knowledge to improve prevention and detection of depression in this patient group. The objectives of this study were to examine: (1) whether indicators of stressors and coping resources were risk factors for developing depression early and later after an acute coronary syndrome and (2) whether prior depression modified these associations. METHODS: The study was a register-based cohort study, which includes 87,118 patients with a first time diagnosis of acute coronary syndrome during the period 2001-2009 in Denmark. Cox regression models were used to analyse hazard ratios (HRs) for depression. RESULTS: 1.5 and 9.5 % develop early (≤30 days) and later (31 days-2 years) depression after the acute coronary syndrome. Among all patients with depression, 69.2 % had first onset depression, while 30.8 % developed a recurrent depression. Most patient characteristics (demographic factors, socioeconomic status, psychosocial factors, health-related behavioural factors, somatic comorbidities, and severity of acute coronary syndrome) were significantly associated with increased HRs for both early and later depressions. Prior depression modified most of these associations in such a way that the association was attenuated in patients with a prior depression. CONCLUSION: Our results indicate that first time and recurrent depression following acute coronary syndrome have different risk profiles. This is important knowledge that may be used to focus future interventions for prevention and detection.