Open Journal Systems

ORIGINAL CONTRIBUTIONS

Received: November 2^nd 2015

Judged: May 2^nd 2015

Impact of frailty over the functional state of hospitalized elderly

Juan Carlos García-Cruz,^a Carmen García-Peña^b

^aUnidad de Atención Geriátrica Hospitalaria, División de Calidad, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social

^bDirección de Investigación, Instituto Nacional de Geriatría, Institutos Nacionales de Salud

Ciudad de México, México

Communication with: Juan Carlos García Cruz

Telephone: (55) 5627 6900, extension 21419

Email: jcgcmd@gmail.com

Background: Frailty in elderly results from impaired physiological reserve in multiple systems. Establishing if frail elderly inpatients develop more functional impairment at discharge, will allow the development of strategies for preventing or limiting the deterioration in this vulnerable group.

Methods: Prospective cohort in 133 elderly inpatients. At admission, frailty, functional status, comorbidity and comprehensive geriatric evaluation were determined. The main outcome was functional state at hospital discharge.

Results: 64 patients presented frailty (48.1%) and 69 did not present that state (51.9%), with a mean age of 73 and 68 years, respectively. Mean decrement in functional state at discharge was −8.06 % (IC 95 % −10.38 to −5.74), from 97.97 % to 89.91 % (p < 0.001) in patients who did not present frailty, and −21.18 % (IC 95 % −24.97 to −17.38), from 87.52 % to 66.34 % (p < 0.001) in frail patients. The difference between groups at discharge was −14.37 % (IC 95 % −16.80 to −11.94, p < 0.001) to the detriment of the frail. Frailty was associated with functional impairment in the univariated and multivariated analysis, beta −13.11 % (IC 95 % −17.45 to −8.78, p < 0.001) and beta −17.27 (IC 95 % −23.27 to −11.28, p < 0.001), respectively. In the final model, frailty (beta −14.73, IC 95 % −19.39 to −10.07, p < 0.001) and cognitive impairment (beta −8.19, IC 95 % −15.28 to −1.10, p = 0.024) predict functional decrement.

Conclusion: Frailty independently predicts functional impairment at hospital discharge.

Keywords: Frail elderly; Aging

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Fragility in the elderly is a state of increased susceptibility due to a lower reserve in multiple physiological systems; it is associated with lower resilience, negative energy balance, sarcopenia, decreased strength, and reduced exercise tolerance. ¹ Chronic disability, isolation, and death are increased in the elderly who have decreased walking speed, less physical activity, weight loss, fatigue, or weakness, all characteristics of fragile subjects.^2,3 The functional status in the elderly is conceptualized as the ability to perform self-care, self-support, and independence activities to perform physical activities, and it is considered an integral marker to determine the health of patients in this age group.⁴ The functional decline in the elderly during hospitalization is associated with prolonged stay, the development of other acute diseases, higher mortality, institutionalization, and rehospitalization. Hospitalization for acute illness triples the risk of developing functional dependence in the next 18 months,⁵ and a third (35%) are discharged from the hospital with reduced functional independence.⁶ The importance of knowing the effect of fragility on the functional status of older adults who are hospitalized is the potential for intervention by implementing strategies in this group vulnerable to hospital admission to delay or limit their functional impairment.⁷ The aim of this study is to determine whether fragile patients upon hospital discharge have greater functional impairment compared to non-fragile patients.

Methods

A prospective cohort was designed. The study population consisted of adults over 60 years of age admitted to any service of the Hospital de Especialidades of the Centro Médico Nacional Siglo XXI for at least 72 hours, who had not been transferred from other units, during the period from February to June 2009. Participants with life-threatening surgical diseases considered grade IV or V on the American Society of Anesthesiologists scale (ASA), with mechanical ventilatory support, metastatic cancer, dementia, multiple organ failure, and ambulatory surgery were excluded. The study eliminated those who did not complete the evaluation upon discharge or who died. In the absence of previous studies evaluating the association looked for, the sample size of 51 patients per group was established based on the clinical relevance^8,9 of finding a 20% difference in functional status at hospital discharge among fragile and non-fragile participants, with a power of 80%, a 95% confidence level, and an alpha error of 5% for a unilateral hypothesis, considering 20% loss. The selection of enrollees was consecutive.

Information collection procedure

The comprehensive evaluation interview was conducted in the first 24 hours of hospital admission and was conducted directly by a doctor specializing in geriatrics to collect information on sociodemographic variables (age, sex, education, marital status, type of residence, and domestic situation) and clinical adjustment variables (comorbidity, depression, cognition, nutritional status, polypharmacy, vision, hearing, history of falls, and self-perceived health status).^10,11 The effect of age on functional status was assessed in two groups: those age 70 or below, and those over age 70. Schooling was evaluated in two groups: basic and intermediate-advanced; basic included literacy, incomplete primary school, complete primary school, incomplete secondary school, and complete secondary school; and intermediate-advanced included high school and college. Marital status was defined in two groups: cohabitating and non-cohabitating; cohabitating included those who are married or those who were cohabiting at the time of the study; non-cohabitating patients were separated, divorced, widowed, or single. The type of housing is defined as homeowner and non-homeowner. The domestic situation was classified into two groups: those living with close relatives, including spouse and children, and other relatives. The geriatric comorbidity index (GCI)¹² was measured with the number of diseases present and their severity. The diseases observed were ischemic or organic heart disease, primary arrhythmias, other cardiomyopathies or cardiopulmonary diseases, hypertension, cerebrovascular events, peripheral vascular insufficiency, diabetes mellitus, anemia, gastrointestinal diseases, hepatobiliary diseases, kidney disease, respiratory disease, Parkinson's and other nonvascular neurological diseases, musculoskeletal diseases, and cancer. The GCI has four classes, depending on the level obtained in the number of diseases present and the level of disease severity obtained. Depression was measured with Yesavage’s Geriatric Depression Scale (GDS) in its short version of 15 questions, and the participant with a score of five or more positive responses was considered to have depressive symptoms.¹³ Cognitive status was evaluated with the minimal mental state examination (MMSE), a score 24-30 without cognitive impairment, a score < 23 with mild to moderate cognitive impairment.¹⁴ Nutritional status was measured with the mini nutritional status assessment in its short version; a score of 12 or more was considered normal, and a score ≤ 11 as at risk of malnutrition.¹⁵ Polypharmacy was defined as taking five or more drugs.¹⁶ Vision was considered impaired with the answer yes to the following question: "Do you have trouble driving, watching TV, or reading in your daily activities because of your vision, despite using glasses?".¹⁷ Hearing was explored with a murmur test; for this, the participant was asked, from a distance of 30 cm behind them: "What is your name?", and hearing was considered altered if no answer or if the answer was incorrect.¹⁸ Prior history of falls was documented with the next question, "Have you fallen in the past year?".¹⁷ The self-perceived health status was approached with the question "How do you rate your health relative to people your own age?"; response options were: very good, good, fair, poor, or very poor.¹⁹

Fragility was considered by a phenotype previously described,² and requires disorder in three or more of the following sections: fatigue, weight loss, physical activity, grip strength, and gait speed. The fatigue section explored the subject by reading the following two statements "I felt that everything I did was an effort" and "I felt I could not go on"; after reading each the participant was asked "How often in the last week did you feel like that?", and it was positive if they answered "often" or "almost always" to any statement.² The weight loss section was positive when the participants answered yes to the question "In the last year, have you lost more than 4.5 kg?” or when a loss of more than 10% of body weight was documented in the last year.² The physical activity section was measured using the International Physical Activity Questionnaire (IPAQ) in its short version, using questions focused on activities in the last week and categorizing participants into low, moderate, or high physical activity; this section was positive when the participant was in the category of low physical activity.²⁰ The grip strength section used a Baseline™ NY brand, model 10533 hand dynamometer; the sitting participant was asked to use the hand they write with to grip with all possible force. The average value was obtained over three attempts; the result was positive with a value ≤ 17 kg and ≤ 30 kg in women and men, respectively, which are the cutoffs reported in the original publication.² The gait speed section was explored with participants walking in a straight line four and a half meters with the stopwatch of Palmary Clock software, v.3.4™, and a time of more than 7 seconds was positive.² Participants were classified as fragile or non-fragile upon hospital admission. 

Outcome variable

The primary outcome of interest was the functional status at hospital discharge. The assessment of functional status at hospital discharge was done by trained personnel who were blinded to the initial results. Functional status was defined as difficulty in performing activities of daily living, including personal and home care, and advanced physical activities with physical functional limitations that cause restriction in basic physical action, including upper and lower extremities.²¹ The stratification of functional independence was used to assess functional status, evaluating performance in 18 areas in activities of daily living, sphincter control, mobility, and executive functions.²² The minimum score is 18, which represents 0% functionality, and the maximum is 126, which represents 100% functionality or maximum independence. The activities of daily living evaluated were feeding, grooming, bathing, dressing one’s upper body, dressing one’s lower body, and using the bathroom. Sphincter control evaluated bladder and rectal control. Mobility evaluated activities of transfer in a chair, in the bathroom, in the shower, walking or using a wheelchair, and climbing stairs. Executive functions assessed comprehension, expression, social interaction, problem-solving, and memory. Each activity was rated with a score of 1 to 7, ranging from full assistance to complete independence, and the sum of the 18 activities resulted in an overall score of functional status.²³ The protocol was approved by the Local Committee on Health Research of the Instituto Mexicano del Seguro Social (IMSS).

Statistical analysis

A comparative analysis was made of the baseline demographic and clinical characteristics among the group of fragile and non-fragile participants with Chi-squared. Functional status at hospital admission was compared to hospital discharge obtained in the fragile and non-fragile group with Student’s t-test for paired samples. The analysis of the mean difference, standard deviation, and confidence intervals of functional status among the fragile and non-fragile groups were performed using Student’s t-test for independent samples. The power obtained was recalculated with the sample size reached, considering a p-value of ≤ 0.05 significant. Simple linear regression analysis was performed with the variables studied, having functional status at hospital discharge as the primary endpoint. The difference of differences between the fragile and non-fragile groups was estimated to discover the prediction coefficient of fragility on functional status within each group and among the study groups. The difference in differences estimates the difference in functional status between hospital admission and discharge in each of the fragile and non-fragile participants, and finally compares this difference between the two study groups.²⁴ A multiple linear regression model was also used and independent variables were added that showed significant correlation. The final model was developed from the saturated model by eliminating variables without statistical significance in the multiple linear regression. Statistical analysis was performed using SPSS software for Windows, version 15. 

Results

The sample selection was 73 fragile participants upon admission and 73 non-fragile participants (Figure 1). Of the fragile participant group, nine did not complete the final evaluation, as did four from the non-fragile group. The evaluation was completed in 64 fragile participants and 69 non-fragile participants. Baseline characteristics (Table I) show that fragile participants have older ages, visual disorders, depressive symptoms, mild to moderate cognitive impairment, higher comorbidity, risk of malnutrition, previous falls, and lower self-rated health.

Measurement by groups of functional status at admission and discharge

The decline in functional status was significant in fragile participants and non-fragile participants, and although all older adults are at risk of developing functional impairment at hospital discharge, this risk is higher in fragile participants. In non-fragile participants upon hospital admission, the average score percentage (standard deviation [SD]) in functional status was 97.97% (2.79), and it decreased significantly upon hospital discharge to 89.91% (9.92) for a -8.06% difference between admission and discharge (p < 0.001, 95% confidence interval [CI] -10.38 to -5.74). In fragile participants upon hospital admission, the average score percentage (SD) in functional status was 87.52% (16.42), which also decreased significantly upon hospital discharge to 66.34% (20.51) for a difference between admission and discharge of -21.18% (p < 0.001, 95% CI -24.97 to -17.38). The fragility group showed an average drop of -14.37% plus functional impairment when compared with the average decline in functional status in the non-fragile group (p < 0.001, 95% CI -16.80 to -11.94) (Table II).

Simple linear regression of the effect of fragility on functional status

The simple linear regression analysis (Table III) shows the effect of fragility on the functional status at hospital discharge with a beta prediction coefficient of -23.56 for the condition of fragility (p < 0.001, 95% CI -29.03 to -18.10). The increase in age negatively affected the functional state with a beta of -8.98 (p = 0.009, 95% CI -13.42 to -4.55) when comparing the group over 70 years with the group under 70 years. Other factors that negatively affected functional status at hospital discharge were a positive GDS screening  with a beta of -9.43 (p = 0.018, 95% CI -17.17 to -1.71) and a result of mild to moderate cognitive decline on the MMSE with a beta of -25.59 (p < 0.001 95% -34.43 to -16.75), and the risk of malnutrition quantified with the mini nutritional status assessment, with a beta -13.12 (p < 0.001 95% CI -19.64 to -6.60) and the existence of visual disorders with a beta -9.51 (p = 0.009 95% CI 16.50 to -2.53). Sex (p = 0.688), marital status (p = 0.331), geriatric comorbidity index (p = 0.053), the presence of polypharmacy (p = 0.799), hearing impairment (p = 0.053), history of falls (p = 0.161), and self-perceived health status (p = 0.444) are not associated with a decrease in functional status at hospital discharge.

Estimating the difference of differences

When comparing the difference in mean differences within and between study groups, the fragility condition remained a predictor of functional impairment and was associated with an average decrease of -13.11 percentage points during hospital stay (p < 0.001, 95% CI -17.45 to -8.78).

Multiple linear regression of the effect of fragility on functional status

The condition of fragility in older adults maintains its ability to independently predict functional impairment at hospital discharge. Table IV shows that the condition of fragility is an independent predictor of loss in the functional state when the multiple linear model is done (beta = -17.27, p < 0.001, 95% CI -23.27 to -11.28), adjusting for measuring functional status at hospital admission and adding the variables of age, geriatric comorbidity index, depression, cognition, nutrition, vision, hearing, falls, and self-perceived health status. Impaired mental state assessed with the MMSE also lets one independently predict the decline in functional status at hospital discharge (beta = -8.98, p = 0.02, 95% CI -16.51 to -1.44). Age older than 70 years (p = 0.824), GCI (p = 0.917), the presence of depressive symptoms (p = 0.693), risk of malnutrition (p = 0.987), the presence of visual impairment (p = 0.304), hearing impairment (p = 0.819), previous history of falls (p = 0.178), and lower self-perceived health status (p = 0.394 ) cannot predict functional impairment. Finally, making the model based on the saturated model, only fragility (beta =-14.73, 95% CI -19.39 to -10.07, p < 0.001) and cognitive impairment (beta = -8.19, p = 0.024, 95% CI -15.28 to -1.10) are associated with decreased functional status.

Discussion

The main finding of this study is that the condition of fragility in older adults can independently predict the decline in functional status at hospital discharge. The significant functional decline at hospital discharge was -8% in non-fragile participants, and -21% in fragile participants, compared to their admission. The negative effect on functional status is of greater magnitude in vulnerable subjects with poor homeostatic reserve, in which the physiological changes associated with aging, such as muscle strength, aerobic capacity, vasomotor stability, respiratory function, and nutritional status, among others, negatively interact when older adults are hospitalized, even starting the second day of hospitalization.²⁵

The fact of quantifying functional status at hospital admission and discharge establishes a temporal relationship that strengthens the causal association of the fragile condition on functional impairment. Fragility causes decreased physiological reserve in multiple systems, making it difficult to maintain homeostasis to address adverse events, such as the exacerbation of chronic disease, acute disease or trauma. The physiological alterations include endocrine disorders (such as increased plasma cortisol and decreased growth hormone and testosterone), immune disorders (such as delayed lymphocyte response, increased interleukin-6 and tumor necrosis factor alpha, both with proinflammatory activities) and the presence of sarcopenia (defined as decrease in musculoskeletal tissue, caused by genetic, metabolic, hormonal, neurological and lifestyle factors).²⁶ The effects on physiological reserve associated with the interaction of these disturbances negatively impacts muscle strength and power, walking speed, basal metabolic rate, and maximal oxygen consumption, all factors involved in the development of fragility² and impacting the functional status. The decline in functional status, which includes the capacity for self-care, self-support, and independence, can be exacerbated by the sum of physiological deficiencies present in fragility when a critical threshold is exceeded.

Comorbidity was not associated with a deterioration in functional status at hospital discharge, but may accentuate the physiological decline of fragility. Although the terms fragility, functional impairment, and comorbidity have been used synonymously in the literature, it is now recognized that each entity has its own pathophysiological process and may, but do not necessarily, coexist in the same individual. Comorbidity in the elderly is associated with increased use of health services, costs, functional impairment and mortality. Comorbidity encourages functional decline by the additive effect of multiple diseases with clinical manifestations, and fragility does this through the additive effect of losses in the physiological reserves in multiple systems, but without clinical manifestations. Age was negatively correlated with functional status at hospital discharge, but this association is lost by including other variables, so functional decline should not be considered an inevitable consequence of aging. The same can be considered for other sociodemographic variables such as marital status, homeownership, and domestic situation with spouse and children, as has been shown previously.²⁷ Cognitive impairment was significantly associated with decreased functional status at hospital discharge, although its clinical relevance for inclusion as part of fragility syndrome needs to be confirmed. The nervous system helps in controlling gait, balance, strength, and muscle mass, all related to functional status and the pathophysiological substrate of fragility. Both physiological decline and the presence of diseases in the nervous system may modify the functional state by further reducing homeostasis,²⁶ and it has been suggested to include cognitive impairment as part of the diagnosis of fragility.³ The strengths of this study include its prospective design without taking data from secondary sources, the use of an operational definition of fragility, the assessment of functional status in 18 areas not limited to activities of daily living, and integrating demonstrated predictors of functional decline into the analysis,^10,11 as well as using the main components of the comprehensive geriatric evaluation. Retrospective cohorts of older adults living in the community have documented 13.6 and 63% of functional impairment at one to seven years of follow-up,^2,28 and up to 8% more functional impairment in patients who are hospitalized compared to those not hospitalized.⁵ Definitions of fragility have been heterogeneous and of varying complexity in existing studies: they range from classifying the fragile subject by the presence of more than one disease, or because they have decreased walking speed, to the inclusion of indices of greater complexity using seventy alterations detected by clinical examination;²⁹ this heterogeneity has led to the timely emergence of proposals to unify the definition of fragility in subsequent studies.^1,26 Predictors of functional decline in the hospitalized elderly have been recognized, but not included as confounding variables in previous studies, and these studies do not reflect the practice of comprehensive geriatric assessment, including the severity of comorbidity taken into account in this work. The limitations to be considered in this study are mainly three. The first is the study population who attends a tertiary care center, which limits the extrapolation of our results to other populations. The second is that post-discharge monitoring of participants was not done to assess the potential reversibility of the functional changes found. The third is that other social variables that might have altered the association of fragility with functional status were not assessed, such as socioeconomic status, paid work, or having social support,²⁷ as well as the time of hospitalization or type of care provided by the hospital. 

The relevance of our results from the health systems perspective highlights the absence of an organizational model of health care aimed at the elderly, analyzing the challenges of integrating processes and services for the care of the vulnerable population identified as fragile, and the potential to change the current service paradigm, which should include the limitation of functional impairment, considered a comprehensive health marker. The objectives of care models in the elderly should be addressed to improve the quality of care and quality of life independently, to increase the satisfaction of the service seeker, and to improve the efficiency of the health system. The difficulties include the proper assessment of this population, the provision of service packages capable of monitoring and evaluation, the cost of interdisciplinary management of chronic diseases with current financial constraints, and the coordination of the physical and human infrastructure of a program of such magnitude in a fragmented service-provision system.^30,31 Early detection of fragile subjects allows among other things for the training of health personnel and the implementation of intervention strategies aimed at fragile subjects to limit or delay their functional deterioration. With the costs of their care, the detection of subjects at risk in a population of increasing magnitude would direct the implementation of health policy planners and decision-makers. Finally, we need deeper knowledge of cost, quality, and access to health services for the elderly, which would make care more effective, equitable and efficient, contributing to improve their health with existing institutions adopting alternative models targeting this vulnerable group. 

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