Prevalence and risk indicators of depression in elderly nursing home patients: the AGED study
Introduction
Depression is a common and disabling psychiatric disorder in later life. It is well known that depression increases mortality and has a negative impact on the well-being and daily functioning of the elderly (Beekman et al., 2002a, Beekman et al., 2002b, Rovner et al., 1991, Wells et al., 1989). In particular, institutionalized elderly people seem to be at increased risk of developing depressive symptoms due to frequently occurring chronic physical illness, a factor that is closely related to depression in old age (Godlove et al., 2000, Gurland et al., 1979, Henderson et al., 1993, Parmelee et al., 1992, Stek et al., 2003).
Among nursing home patients, prevalence rates have been found ranging from 6% to 26% for major depression, from 11% to 50% for minor depression and from 30% to 48% for depressive symptoms, as measured by symptom rating scales (Jongenelis et al., 2003).
Despite its high prevalence, depression remains poorly recognized in the nursing home environment. By implication it is under-treated, whilst there is ample evidence of treatment efficacy (Katz, 1993, Llewellyn-Jones et al., 1999, Rovner, 1993). To enhance detection, an important strategy might be to identify patient characteristics associated with a high risk of depression. Nevertheless, nursing home-based studies on risk indicators of depression are scarce, and the findings are conflicting. For instance, with regard to cognitive impairment and functional limitations, not only positive and negative, but also a lack of associations with depression have been reported. Concerning visual and hearing impairments, both positive associations and an absence of associations with depression have been found (Gerety et al., 1994, Godlove et al., 2000, Henderson et al., 1993, Kay et al., 1987, Parmelee et al., 1989, Parmelee et al., 1992, Rovner et al., 1991, Rozzini et al., 1996, Shah et al., 1992). Remarkably, in contrast with the findings in community-dwelling elderly, no relationship between depression and gender or age has been found in nursing home-based studies (Gerety et al., 1994, Godlove et al., 2000, Henderson et al., 1993, Rozzini et al., 1996, Schumacher et al., 1997). These results suggest that depression in nursing homes may have a specific profile of risk indicators. In addition to physical health, other, perhaps more social-environmental or care-related factors might be responsible for developing depressive symptoms during nursing home residence. A group that is of special interest consists of patients who have depressive symptoms, without meeting the DSM-IV criteria for depression. It is of clinical importance to identify these patients in order to evaluate their need for special care and treatment.
The increasing number of elderly people in the population will probably lead to an increase in the number of nursing home patients. Insight into the prevalence rates and risk indicators of depression, is therefore, of great importance in order to develop adequate prevention and treatment strategies.
The aim of the present study was to investigate the prevalence of depression, measured with a rating scale and a diagnostic instrument, and to identify risk indicators of depression in the nursing home population.
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Sample and procedure
This study is based on data collected in the Amsterdam Groningen Elderly Depression (AGED) study. All nursing homes with both 24 h nursing staff and medical care in the North West of the Netherlands were asked to participate. Nursing homes for patients with specific illnesses (e.g. Huntington, Korsakow, rheumatic diseases) or religion categories were excluded. Also excluded were homes involved in major reorganizations or refurbishing, because of possible influence on the mood of the
Results
The source population for this study consisted of 1422 nursing home patients. Of these, 350 patients were finally included in this study (see Fig. 1).
Demographic characteristics are shown in Table 1.
The overall point prevalence for GDS scores >10 was estimated at 44.3%. In terms of diagnostic categories, the prevalence of sub-clinical depression was 24.0%, for minor depression the prevalence was 14.1% and for major depression it was 8.1% (see Table 2). Demographic, health and psychosocial
Discussion
This study investigated the prevalence and risk indicators of depression in older people residing in nursing homes in the Netherlands. The results confirm the previously reported high prevalence of depression in this frail population. In the present study the prevalence of major depression and minor depression was found to be 8.1% and 14.1%, respectively, while a further 24% of the patients had significant depressive symptoms but no diagnosis of depression according to the DSM-IV (research)
Acknowledgments
The AGED study was primarily funded by the Netherlands Organization for Scientific Research (NWO; grant number 94033041). Additional financial support by Lundbeck B.V. was gratefully acknowledged.
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