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The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 63:707-714 (2008)
© 2008 The Gerontological Society of America

Self-Reported Lack of Energy (Anergia) Among Elders in a Multiethnic Community

Huai Cheng, Barry J. Gurland and Mathew S. Maurer

1 Stroud Center for Studies of Quality of Life, 2 Division of Geriatric Medicine and Aging, and the 3 Division of Cardiology, Section on Geriatric Cardiology, Columbia University, New York.

Address correspondence to Mathew S. Maurer, MD, Clinical Cardiovascular Research Laboratory for the Elderly, Columbia University Medical Center, 5141 Broadway, 3 Field West- Room 018, New York, NY 10034. E-mail: msm10{at}columbia.edu


   Abstract
Top
 Abstract
Methods
 Results
 Discussion
 References
 
Background. Lack of energy, "anergia," is a possible central feature for identifying, evaluating, and treating elders with health-related problems in quality of life.

Methods. A survey was conducted on a randomly selected stratified sample (N = 2130) of three ethnic groups of community-residing elders in a defined urban geographic area: the Northern Manhattan Aging Project (NMAP). The participants were Medicare beneficiaries living north of 150th Street in Manhattan. The criteria for anergia were based on the presence of the major criterion "sits around a lot for lack of energy" and any two of six minor criteria. Self-reports were gathered using a computer-assisted, rater-administered interview (the Comprehensive Assessment and Referral Interview; CARE) covering: function (basic activities of daily living [ADL] and instrumental ADL [IADL]); features of geriatric syndromes such as self-rated physical health, depression, pain, respiratory distress, trouble sleeping, cognitive impairment, and cardiovascular syndromes; social isolation; and healthcare utilization. Short-term (18-month) and long-term (6-year) mortality were derived from the National Death Index.

Results. Three hundred eighty-six people (18% of the sample) met criteria for anergia. Anergia was more common in women than men (22% vs 12%, p <.01), in unmarried than in married persons (21% vs 13%, p <.001), and with advancing age. People with anergia used more hospitalizations, office visits, emergency room visits, and home care services and, had higher mortality rates. In multivariate analyses, the following factors had independent associations with anergia: female gender, impaired physical function and IADL, depression, pain, respiratory symptoms, urinary incontinence, hearing difficulty, feeling dizzy or weak, and social isolation and disengagement. These factors could be the initial candidates for clinical investigation of anergia of undetermined origin. Among people with anergia at baseline, 31.3% (n = 121) had persistent anergia and 33.9% (n = 131) recovered over a follow-up period of 18 months.

Conclusions. Anergia in multiethnic older adults is associated with a range of clinical symptoms and diseases, with extensive health services use, and with increased mortality.

Key Words: Anergia • Energy • Multiethnic • Elders

IN geriatric medicine, the term "syndrome" refers to multiple abnormalities that "run together" to cause a single phenomenology. Geriatric syndromes are characterized as conditions experienced by older persons that are chronic, may be triggered by acute insults, and often are linked to subsequent functional decline (1). From a clinical perspective, such syndromes are manifest conditions in which the chief concern or symptom(s) are expressed by the patients or their caregivers, do not result solely from discrete diseases but also from accumulated impairments in multiple systems (2), and develop when the accumulated effect of these impairments in multiple domains compromises compensatory ability (3,4). Under such circumstances, the adverse results include functional decline and adverse health outcomes such as increased hospitalization or mortality (3,5–8).

Frailty in older persons has attracted considerable attention in both clinical (7,9) and research (10) arenas in geriatrics, as well as in health policy, and has been considered as a geriatric syndrome. There is a gathering consensus that the core feature of frailty is high vulnerability to a variety of stressors and functional decline, with or without intercession of acute incidents such as falls, fractures, or episodes of illness. Worsened morbidity and disability, health care usage, and mortality are consequently increased (7,11). Conceptually and with some evidence, multiple and interactive organ systems are involved in the causal chain of frailty, particularly muscles and bone (12), but also neurohormonal (13), nutritional (14), inflammatory (8), and potential genetic mechanisms (10). Accordingly, consensus and suggestions are proposed for preventing or reversing this condition (10). Nevertheless, from a clinical perspective, the identification of older individuals with frailty has not been facilitated in clinical practice, possibly in part because of its asymptomatic nature and because of the need for performance-based measures (e.g., walking speed, handgrip strength).

Predominant among the signs and symptoms of frailty defined by different criteria are weakness, lack of physical and mental energy, and exhaustion (7,9–11,15). However, lack of energy has not been used as the sole criterion to defining a geriatric syndrome. Self-reported lack of energy might be a more easily identifiable condition than frailty because of its basis as a chief complaint or concern. However, it is unknown whether this predominant symptom experienced by older persons has clinical relevance among community-dwelling multiethnic older persons. Accordingly, in this epidemiological study we examined the association between self-reported lack of energy and the cardinal features that constitute a geriatric syndrome. Specifically, we explored whether lack of energy is a prevalent concern of patients and warrants consideration as a geriatric syndrome because of a substantial association with etiologic factors of geriatric relevance such as multiple comorbidities, especially functional, cognitive, or affective disorders, and because of an adverse impact on quality of life and mortality.


   METHODS
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Study Design and Population
Data were obtained from the Northern Manhattan Aging Project (NMAP), a longitudinal study funded by the National Institutes of Health at Columbia University between 1989 and 1995, the methods of which have been described previously (16,17). In brief, a random sample of Medicare beneficiaries was recruited who were 65 years old or older and were living in a bounded "target" geographic area of 13 adjacent census tracts north of 150th Street in Manhattan, a multiethnic community. According to the 1990 census, 9349 people 65 years old or older lived in this area. The Health Care Financing Administration provided access to a random sample of approximately half of these recipients. In this group, 4865 individuals were divided into 37 identical replicates, representing the demographic characteristics of the cohort. These individuals were sent a letter from the Health Care Financing Administration explaining that they had been randomly selected to participate in a study of aging by investigators at Columbia University, New York, NY. Potential participants in the survey were drawn by random methods in replicated subsamples equally from the three cultural groups until the numbers of elders in any group were exhausted or the total number of elders interviewed exceeded 2100. Subsequently, it was determined that 470 (9.7%) had died, 896 (18.4%) no longer lived in the region, 47 (1%) were ineligible, and 1324 (37%) did not wish to participate. The proportions of individuals within each ethnic group, as identified from Health Care Financing Administration records, differed only slightly between the total sample and those who participated (total sample: African American, 35.4%; Hispanic, 35.4%; white, 29.2%; participants: African American, 35.2%; Hispanic, 38.9%; white, 25.8%). Poverty, crime, and unemployment rates are high in the study target area.

A total of 2130 participants recruited from three cultural groups were evaluated at baseline in 1989 and every 18 months thereafter, for a total of three waves of interview. Trained research assistants collected data using a computer-assisted, rater-administered interview (the Comprehensive Assessment and Referral Interview [CARE]) covering a wide range of qualities of life, with particular attention to details of functioning in daily tasks of living; physical, cognitive, affective, social, and psychological status; as well as symptom syndromes and health care utilization (18,19). Interviews were conducted in either English or Spanish. The Columbia University Institutional Review Board approved this project. All individuals provided written informed consent.

Definition of Lack of Energy (Anergia)
We operationalized a definition of anergia based on the responses to seven items related to energy level in the NMAP data set. Anergia was defined as the presence of the major criterion "Sits around a lot for lack of energy" and any two of six minor criteria: "recently not enough energy," "felt slowed physically in past month," "doing less than usual in past month," "any slowness is worse in the morning," "wakes up feeling tired," and/or "naps (>2 hours) during the day."

Quantification of Demographic, Clinical, and Function Parameters
Demographic and socioeconomic variables.-- Elders were assigned to the three ethno-racial groups on the basis of their self-attribution that they were of Hispanic origin or descent and, if not, that they were non-Hispanic white or African American. Educational achievement categories are 0–4 years of school completed, 5–11 years, and 12 or more years. Household income was elicited by asking the participants to select their monthly income bracket from a list displayed on a card; income was then collapsed into three categories. All main sources of income were specifically mentioned, including wages, salaries, social security or retirement benefits, help from relatives, and rent from property.

CARE domains.-- Items from several standard measures of functioning were embedded in the CARE interview: Basic and Instrumental Activities of Daily Living (ADL and IADL) (20,21), hierarchical categories of activity limitation and mobility (18), scales for self-rated health and life satisfaction, and a hierarchical index of severity of affective suffering that was used in theses analyses and also to form a proxy for a clinical level of depression (22). A well-validated scale of cognitive impairment was treated as a continuous variable and also as a screen for referral to a research team that diagnosed dementia after full investigation (mostly Alzheimer or vascular types) as described elsewhere (16,17).

Geriatric and other clinical syndromes.-- Previous literature has demonstrated that disparate geriatric syndromes may cluster together because of shared risk factors. Therefore, we explored the association of anergia with other well-defined geriatric syndromes including falls (at least once in the last year), self-reported urinary incontinence and feeling dizzy or weak, and self-neglect based on the appearance and grooming of the participants observed by the interviewer.

To explore the potential reasons that a participant with anergia might present to a clinic, we evaluated the association of anergia with various comorbid conditions, including arthritis (or pain or stiffness in or around the joints), respiratory complaints, cardiovascular symptoms, sleep disorders, reduced mobility, incontinence, depression, sensory deficits, and neurological disorders. These were evaluated by historical information regarding the onset, duration, and severity of the participant's symptoms and by "homogeneous" indicator scales that were previously derived using latent class analysis. Their content, clinical and face validities, inter-rater and internal consistency reliabilities (23,24), as well as concurrent and predictive validity for future morbidity and mortality (25), have been reported.

Healthcare utilization.-- Healthcare utilization included self-reported overnight hospitalization, seeing a doctor in a clinic, emergency room visit, and home care services including a nurse, home attendant, home health aide, homemaker, or other auxiliary health professional.

Longitudinal follow-up and mortality.-- Participants were followed at intervals averaging 18 months. Participant interviews, but not informant interviews, were repeated. The National Death Index (NDI) was used to confirm the status of the patients as deceased, likely deceased, or alive, with the former two categories combined to indicate mortality.

Statistical Analysis
The prevalence of anergia and its components was determined. To investigate the association of anergia with personal, health, social, and service characteristics as well as mortality, we performed bivariate analyses comparing the cohort with and without anergia. For continuous variables, Student's t test for unpaired comparisons was used, and for dichotomous variables Chi-square analyses were used. Subsequently, a multivariate logistic regression model was used to obtain mutually adjusted associations of anergia with demographics and all other potential risk factors for anergia, including all variables that were significant at p <.10 in bivariate analysis and selected variables considered of special relevance (e.g., race), even if bivariate analyses were not significant. Data were presented as odds ratios and 95% confidence intervals. A two-tailed p value <.05 was considered statistically significant. All analyses were performed in SPSS 11.0 (SPSS Inc., Chicago, IL).


   RESULTS
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Discussion
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The criteria used to identify participants with anergia along with their prevalence in the population are shown in Table 1. Apart from 8.4% of participants who could not be classified because of missing data, at least one complaint of lack of energy was presented by 66% of participants; 18% of the population met criteria for anergia.


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  		Table 1. Prevalence of Components Used to Define Anergia.

 
The demographics of the population are shown in Table 2. The mean age is 74 years and ranges from 65 to 104 years, with about 20% of participants being older than 80 years. It is predominately a cohort of Latinos and African Americans, but non-Hispanic whites are also represented. The majority are women, with low rates of higher education and high rates of low income. The prevalence of anergia is more common in women than men, with advancing age and with lower educational and income levels, whereas being married is associated with a lower prevalence of anergia (Table 2).


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  		Table 2. Demographics of Total Northern Manhattan Aging Project (NMAP) Population and by Presence of Anergia.

 
Anergia was associated with worse physical function and health (Table 3). Persons with anergia, compared to the rest of the population, related their health more often as fair or poor as opposed to excellent, could walk fewer blocks without resting, reported more limitation in ADLs and IADLs, and used an assistive device twice as often. The association of anergia with dementia was also high, as was the association with restricted social function.


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  		Table 3. Association of Anergia with Various Domains of Function and Mortality.

 
Participants with anergia were more likely than the rest of the sample to rate their life satisfaction as fair or poor, and as worse on the seven criterion-based hierarchical categories of severity of nonsomatic symptoms of depression (affective suffering) (22). Anergia and affective suffering were significantly but only modestly associated (r = 0.35, p <.001). Moreover, less than half of the participants meeting criteria for anergia met criteria for clinically relevant depression (based on the worst three categories of affective suffering). Conversely, the majority of participants with clinically relevant depression did not meet criteria for anergia, suggesting that a majority of what determines anergia is to be found outside of the construct of depression.

Anergia was associated with a significantly increased chance that participants would complain about problems with their joints (arthritis, joint pain, stiffness, or swelling around the joints or in the muscle) or would take medications for pain. Similarly, anergia had strong associations with respiratory complaints, cardiovascular symptoms, sleep disorders, mobility problems, incontinence, sensory deficits, and neurological disorders. Accordingly, anergia is a concern that is likely to be encountered by all medical and surgical providers of care to older persons. In fact, a physician had seen >90% of elders with anergia in the previous year. The proportion and number of days hospitalized and the number of emergency room visits were more than doubled in the anergic as compared with nonanergic cohort, as was the use of home care services (Table 3). After 6 years of follow-up, one fifth of the participants were deceased, and in bivariate analyses anergia was associated with a higher mortality at both 18 months and after 6 years of follow-up.

Multivariate analyses (Table 4) revealed factors that were independently associated with anergia: being female, physical function, IADLs, depression, pain, respiratory symptoms, urinary incontinence, hearing difficulty, feeling dizzy or weak, and social isolation and social disengagement,. These factors are candidates for a focus of initial investigation of otherwise undetermined anergia.


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  		Table 4. Unadjusted and Adjusted Associations Between Characteristics of Study Participants and Anergia.

 
Among people with anergia at baseline (n = 386) who were alive and interviewed at a follow-up period of 18 months (n = 252), 48.1% had persistent anergia. Respiratory symptoms, urinary incontinence, poor self-rated health, and social disengagement were significantly associated with persistent anergia. The incidence of anergia was 7.1% (n = 117) over the same time period. Being female, walking <6 blocks without resting, poor self-rated physical health, impaired IADL, affective suffering or nonsomatic symptoms of depression, pain, respiratory symptoms, dizziness, urinary incontinence, social disengagement, and social isolation were significantly associated with developing anergia over this follow-up period.


   DISCUSSION
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The principal results of this epidemiologic investigation are that anergia, as defined is: (i) common (18%) among a sample of multiethnic community-dwelling older persons; (ii) associated with multifactorial risk factors and comorbidities suggesting an underlying interplay of biological, psychological, and social factors; and (iii) associated with increased health care utilization and mortality. Collectively, these findings would suggest that anergia warrants consideration as a geriatric syndrome.

Lack of energy, a central feature of anergia, has been reported in various disorders including cancer (26), chronic kidney disease (27), arthritis (28), human immunodeficiency viral infection (29), anemia (30), heart failure (31), chronic lung disease (32), and advanced chronic disease Among the U. S. general population, fatigue, an analogous concept, has been noted in approximately 10–25% (33,34). Although lack of energy in nonelderly adults has received considerable attention, and severe forms that are persistent and unexplained (e.g., chronic fatigue syndrome) have invoked considerable clinical and research interest (35,36), relatively little research has focused on lack of energy in older individuals. Previous epidemiologic study of attendees of a general practice (37) and of a general population (38) did not emphasize the impact in elderly persons.

Two studies did focus on lack of energy in older individuals. Among 199 older residents of a single residential care facility (39), almost all (195; 98%) reported persistent (median duration of 44 weeks) lack of energy. Severity of lack of energy was associated with depression, functional capacity (e.g., walking speed and IADLs) and pain, as well as the number of medications, but not with age, gender, cognitive status (as assessed by MMSE), or number of medical diagnoses; these associations are consistent with our findings. Also supporting our findings is a prospective study of individuals aged 75–80 years (40) in which sustained tiredness was a strong predictor of functional disability and mortality within the following 5 years; this effect appeared to be mediated in part through declines in functional ability. Additionally, tiredness was associated with increased subsequent hospitalization and use of home services (41,42).

The label of anergia draws a distinction from the more commonly used clinical terminology—lack of energy, fatigue, or exhaustion. Fatigue or exhaustion conventionally defines a condition of "lassitude or weariness or a reduction in power following a period of prolonged activity or stimulation or the result of either bodily or mental exertion." The specificity of fatigue for delineating postexertional situations is a cardinal factor that distinguishes it from anergia; the latter constituting a more persistent state. Anergia is also related to certain aspects of frailty but does not require the key criteria or frailty: objective weight loss, weakness of grip, poor endurance (exhaustion), slowness, and low physical activity (7,11). Thus in clinical settings anergia, being recognizable as a "chief complaint or concern," is a more readily identifiable condition than frailty is. Moreover, anergia, as defined currently, has a prevalence in community-dwelling elderly persons that is more common than that of frailty (18% vs 7%) (7). Additionally, because it is a reflection of one of the core conditions that defines frailty, anergia could be a meaningful outcome to measure in older individuals during intervention trials.

Although bivariate analysis did not demonstrate an association of education and race with anergia, these measures are tightly intertwined with other confounding factors. Accordingly, using further multivariate analysis, we found that self-reported race (African Americans as compared to Latinos) became significantly associated with anergia. Additional one-variable-at-a-time models showed that five variables together eliminated the significant association of race with anergia: depression, feeling dizzy or weak, seeing difficulty, hearing difficulty, and social disengagement. Such intertwined relationships among culture, ethnicity and race, symptoms, social context, and anergia should be explored further.

As a result of the multiple independent associations of anergia with numerous clinical symptoms and syndromes, as well as with other geriatric syndromes, anergia will be encountered not only by geriatricians but also by other health care providers in different clinical settings. The multivariate analyses suggest that physical function, IADLs, depression, pain, respiratory symptoms, urinary incontinence, hearing difficulty, feeling dizzy or weak, social isolation and social disengagement, and female gender are independent risk factors for anergia, should be investigated initially, and could become potential targets for intervention. Interventions targeting anergia are likely to require an interdisciplinary approach. The biological and physiologic pathways that cause or contribute to the phenotype of anergia are likely to be complex and not a single disease model (4,11,15). Because of independent association of lack of energy with social isolation, interventions may need to expand beyond the traditional clinical settings and use community-based activities and engagement programs. The mechanisms of how multifactorial risk factors and etiologies interact to result in a lack of energy are not answered by our study but warrant additional investigation.

Among the multiple associations of anergia, there are none that are necessary or sufficient for the presence of anergia as defined (i.e., no single cause of anergia has been identified). Occam's razor would point to a common mechanism linking multiple causes to the anergic outcome. Basic and applied research can be organized to discover and treat the common mechanism (or set of mechanisms). Accordingly, the data presented highlight the potential importance and power of anergia and pose complex questions, which are ripe for further investigation, including: Why is anergia associated with so many conditions? Why do some people with particular conditions have it and some do not? Why does it aggravate the prognosis? Should it be directly treated or be addressed only through the underlying condition? Additionally, we would note that frailty and anergia at present could be seen as distinct but reciprocally informative strategies for basic and clinical geriatric research. Future comparisons may involve (i) the predictive power of anergia with that of frailty and (ii) whether the discovery of etiology, biological pathways, and interventions is more likely to make progress with a strategy using anergia or frailty as the initial starting point, among others.

This study has several limitations. Data were derived from a single, albeit large and multiethnic data set that was collected almost two decades ago. This is a study of all Medicare-eligible participants in a geographic area in a multicultural population having a low education and low income and living in a high crime area. Accordingly, response rates were low and could have biased estimates of the frequency of anergia. Confirmation of these findings should be sought in additional, current population-based studies of older individuals. The data used are predominately self-reported, raising the possibility of a dependent error resulting in a false inflation of relationships due to combined measurement error as well as reporting error. Additionally, the current data set lacks data on comorbidities that are likely to be associated with anergia (e.g., anemia, renal failure, congestive heart failure, diabetes, and chronic obstructive pulmonary disease). Future analyses in other data sets able to control for these data will be extremely valuable. The significant percentage of participants that were lost to follow-up limits our ability to evaluate chronicity. The criteria for anergia used in this sample should be considered preliminary, and formalized criteria for anergia will require prospective investigation and future study to define consensus. Finally, because our analyses are largely cross-sectional, we do not have the sequence that would facilitate inferences regarding causality. Further longitudinal analyses of this and other data sets can provide insights regarding the pathways by which anergia could cause or contribute to functional decline and adverse outcomes.

Summary
Among multiethnic community-dwelling elderly people, anergia is an extremely common and chronic complaint that is independently associated with multiple clinical symptoms and diseases, other geriatric syndromes, comorbidities, social isolation, increasing health care utilization, and long-term mortality. Accordingly, anergia fulfils all of the main features that constitute a geriatric syndrome. Further investigations for potentially effective interventions targeted at anergia in older persons appear warranted.


   Acknowledgments
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We appreciate suggestions for this article from Dr. Rafael Lantigua, as well his leadership, with the late Dr. David Wilder, in the conduct of the data collection.


   Footnotes
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Decision Editor: Luigi Ferrucci, MD, PhD

Received March 12, 2007

Accepted October 22, 2007


   References
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