Aging is a universal, multifactorial, progressive process that occurs gradually, causes impairment1 and includes psychosocial and economic factors. It leads to a physiological decline in all body systems, contributing to reduced physiological reserve1 and making individuals susceptible to disability and disease. In older adults, adverse health conditions contribute to functional decline.2 This decline is a determining factor in negative health outcomes, including functional dependence, falls, institutionalization, hospitalization, and risk of death.3

The main causes of hospitalization in this population are cardiorespiratory diseases and orthopedic injuries,4 which contribute to extended length of stay that involve patients spending 83% of their time lying in bed.5 Bed rest exacerbates the negative effects of hospitalization on body systems, including psychological and cognitive aspects.6,7 These negative effects contribute to reduced physical performance and functional capacity for activities of daily living (ADLs) at discharge and in the long term.2,8,9

Functional decline after hospitalization affects approximately 30% of older adults.10 Research indicates that this decline seems to be associated with poor gait speed, balance, and muscle strength at admission2,9 and that performance in handgrip strength (HGS) and the Short Physical Performance Battery (SPPB) at baseline could predict this decline.9,11-14 Elucidating the relationship between physical performance at admission and functional capacity decline during the length of stay in Brazilian older adults is important in helping health professionals make decisions about interventions that can prevent this decline and improve healthcare outcomes. However, the relationship between physical performance at baseline and decline in functional capacity in Brazilian older adults remains unclear. Furthermore, in international studies, only one study, in non-hospitalized older adults, assessed the predictive capacity of both HGS and the SPPB in the emergence of functional disability.13 Previous studies selected participants based on specific health conditions9,12 and did not exclude those who died, classifying patients who died as disabled,12 which may have produced biased results.

Assessing physical performance on admission and the resulting changes in functional capacity in older adults who use Brazilian public health services would contribute to elucidating the effects of hospitalization. Additionally, investigating the possibility of using geriatric assessment tools in a hospital setting as prognostic factors would help stratification of the population at risk of functional capacity decline and allow public health services in Brazil to establish policies that aim to improve quality of life, optimize care costs, and better manage the negative effects of hospitalization, thereby providing better likelihood for older adults to return to the community after treatment.

The present study aimed to investigate the influence of physical performance level at admission on functional capacity and functional capacity decline at discharge. The secondary objective was to determine whether performance assessment tools used at baseline can be predictive of functional decline. We hypothesized that Brazilian older adults experience functional capacity decline during hospitalization and that physical performance on admission influences functional capacity at discharge. We also hypothesized that physical performance assessment tools can predict this decline.

All patients admitted to the Medical Clinic and Cardiology units during the study period were assessed based on the eligibility criteria, with 339 undergoing initial screening. Of these, 255 were excluded for not meeting the eligibility criteria or refusing to participate. Eighty-four individuals were assessed based on the clinical, sociodemographic, hospitalization, and physical performance on admission, with 75 completing the longitudinal follow-up at discharge (Fig. 1).

Fig. 1.

Flowchart of participant selection and monitoring. HGS, handgrip strength; SPPB, Short Physical Performance Battery.

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Of these 75 participants, 39 (52%) were from the Medical Clinic and 36 (48%) from the Cardiology unit. The median time between admission to the units and participant assessment was 1 day (interquartile range [IQR]= 1–2 days). Median hospitalization time was 18 days (IQR= 7.5–30 days).

Participants had a median age of 71 years (IQR= 65–78 years) and 4 years of schooling (IQR= 2–11 years), most were sedentary (80%) and earned less than or equal to one minimum wage a month (77.3%). Cardiovascular diseases were the main cause of hospitalization (49.3%). Participant characterization according to clinical, sociodemographic, hospitalization, and physical performance on admission variables is presented in Table 1.

The median time for functional capacity reassessment was 4 days after discharge (IQR= 3–8.5 days). There was a significant difference in scores of the Katz index and the Lawton & Brody questionnaire at hospital admission and discharge (Katz admission= 5[5–6] vs. Katz discharge= 5 [3–6], p = 0.002 / Lawton & Brody admission= 20[17–21] vs. Lawton & Brody discharge= 14[10–18], p<0.001). Functional capacity for BADLs and IADLs declined in 39% (n = 29) and 79% (n = 59) of the participants, respectively.

Simple linear regression indicated that 18 to 25% of functional capacity for BADLs and IADLs at discharge was explained by physical performance on admission (Table 2). Multiple linear regression adjusted for confounding variables demonstrated that physical performance according to the SPPB and functional capacity for BADLs on admission were related to functional capacity for BADLs at discharge, explaining 35% of this capacity [p = 0.001; R²=0.35]; HGS performance and functional capacity for IADLs on admission were related to functional capacity for IADLs at discharge, explaining 29% of this capacity [p = 0.007; R²=0.29] (Table 2).

Simple binary logistic regression showed that performance in HGS (OR=0.94 [95% CI: 0.88, 0.99]) and in the SPPB (OR=0.84 [95% CI: 0.74, 0.95]) on admission was associated with functional capacity decline for BADLs at discharge (Table 3). With multiple binary logistic regression with these two physical performance variables, only the model containing SPPB performance and functional capacity for BADLs at admission was significant (X²=13.075; p= 0.001, R²Nagelkerke=0.217) in predicting functional decline for BADLs at discharge. One additional point in the SPPB reduced the chance of this decline by 20.9% and three additional points by 50.5%. Simple binary logistic regression found no association between physical performance on admission and reduced functional capacity for IADLs at discharge, with only BMI and functional capacity for IADLs on admission as significant predictors (X²=22.851; p= 0.004, R²Nagelkerke=0.407) (Table 3).

With the analysis of the ROC curves, the AUC values for the SPPB (AUC=0.67 [95% CI: 0.55, 0.79]) and HGS (AUC=0.65 [95% CI: 0.51, 0.77]) at admission were significant in identifying functional decline for BADLs, but not IADLs (p>0.05) (Fig. 2A and B). Using HGS to predict the risk of reduced functional capacity for BADLs, sensitivity and specificity analyses identified 21 kgf as the most accurate cutoff point in predicting the risk of functional capacity decline in the present sample (sensitivity = 65.5%, specificity = 58.7%, VPP= 50%, and VPN= 73%). When the SPPB was used to predict the risk of functional decline for BADLs, a cutoff of 5 points was most accurate at predicting risk of decline (sensitivity = 62%, specificity = 67%, VPP= 54%, and VPN= 74%).

Fig. 2.

ROC curves for identifying functional decline at discharge. AUC, area under the ROC curve, BADLs, Basic activities of daily living; IADLs, Instrumental activities of daily living; HGS, handgrip strength (kgf); SPPB, Short Physical Performance Battery (total score).

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In this longitudinal study with Brazilian older adults admitted to two clinics at a general public hospital in the Brazilian Federal District (DF), we found that hospitalization negatively affects functional capacity for BADLs and IADLs. Lower HGS and SPPB performances at admission were predictors of functional capacity decline at discharge. Additionally, the results of this study demonstrated that HGS and SPPB performance can be used on admission to screen for risk of reduced functional capacity for BADLs after hospital stay in hospitalized older adults.

Hospitalization contribute to extended periods of bed rest, which lead to physiological changes in the body's systems.6,7 In older adults, among other factors, these changes contribute to reduced muscle strength, physical performance, and aerobic capacity,8 limiting execution of ADLs. In the present study, functional capacity for BADLs declined in 39% of the sample, corroborating previous research that reported reductions in 21.6 to 52.2% of patients.9,10,13,26,28-30 By contrast, to date, reduced functional capacity for IADLs is little studied in hospitalized older adults, with decline reported in 18% of participants28 lower than that detected in our study (79% of patients who declined). These findings reflect the different population characteristics that contribute to limitations in IADLs.31 Factors associated with vulnerability in older adults, such as low income32 and educational levels,33 were present in our sample, which may have influenced the greater number of patients who declined in functional capacity for their IADLs.

The results of the present study also demonstrated that physical performance on admission was associated with functional capacity and functional capacity decline at discharge, corroborating the findings of previous research.2,9,30,34 Other studies demonstrated that older adults with poor physical performance on admission to hospital exhibited significantly worse decline in functional capacity at discharge when compared to those with good physical performance,9 and were 3.19 times more likely to develop limitations in BADLs and IADLs.34 These findings may be associated with the fact that older adults with poor physical performance on admission are more functionally dependent, which tends to increase bed rest time and exacerbate physical losses, contributing to further functional capacity decline.

When considering other factors, only physical performance in the SPPB remained a predictive variable of functional capacity for BADLs at discharge. Good performance in the SPPB reduced the chance of functional decline by 21%, corroborating the findings of a previous study that reported 18 to 20% less likelihood of decline in older adults who performed well in the SPPB.11 The relationship between HGS and functional capacity for ADLs is still debated.12,13,34 Consistent with the present study, another investigation found no association between HGS and functional capacity.13 However, older adults with low HGS had a 1.51 greater chance of functional decline for BADLs34 and those with good HGS on admission were 13% less likely to experience a decline.12 These differences can be attributed to other factors that, in addition to strength, are important in physical performance, such as motor control35 and motor coordination,36 and in functional capacity, including flexibility and aerobic endurance.37

In relation to functional capacity for IADLs at discharge, an association was only observed with HGS. However, this correlation was not strong enough for good HGS performance to lower the risk of functional decline (p = 0.724). These findings differ from previous studies that demonstrated a relationship between HGS and SPPB performance and functional capacity for IADLs.2,9,14,34 IADLs are more complex activities and the ability to perform them depends on factors beyond physical performance, such as educational level, age, sex, engaging in physical activity, comorbidities, continued-use of medication, and income.31 Moreover, in the present study, low BMI was associated with reduced functional capacity for IADLs. Previous results also identified BMI as a predictor of this decline, with limitations in IADLs reported more frequently in underweight older adults.31 This population is more prone to developing sarcopenia and frailty,38 contributing to muscle weakness associated with hospitalization and reduced functional capacity and physical performance.39

Our study also demonstrated the prognostic value of the physical performance assessment tools (HGS and SPPB) in hospitalized Brazilian older adults. The most accurate cutoff points of 21 kgf for HGS and 5 points for the SPPB were considered capable of predicting the risk of decline in functional capacity for BADLs. Unlike previous research that identified an HGS cutoff point of 20.65 kgf only for hospitalized older men,12 the cutoff in our study was suggested for inpatient older adults of both sexes. With respect to the SPPB, our findings are consistent with those of another investigation that also recommended a cutoff of 5 points.11 The sensitivity values recorded in the present study indicated that HGS and the SPPB can detect more than half of individuals at risk of functional capacity decline. Additionally, negative predictive values also demonstrated that older adults who performed well in these tests (HGS >21 kgf and SPPB >5 points) were unlikely to experience functional decline. Although these results are interesting, with cutoff points close to those found in previous research, analyses in the present study are preliminary and showed low predictive capacity, requiring caution in interpreting the results.

In this context, the findings obtained here showed that hospitalization has a significant impact on functional capacity at discharge in Brazilian older adults. In addition, 50% of participants did not undergo physical therapy during their hospital stay, because older adults with a higher level of independence on admission are evaluated and guided to maintain their functioning, but do not receive treatment due to the low number of physical therapists. The lack of physical therapy treatment could accelerate functional capacity decline, because evidence indicates that the more time spent on in-hospital physical therapy, the less functional capacity declines.40 Our results demonstrated that physical performance is predictive of functional capacity at discharge and that HGS and the SPPB can be used as tools to identify older adults at risk of functional capacity decline. They also indicate that the level of independence of older adults for BADLs and IADLs on admission is associated with the ability to perform these activities upon discharge. These findings contribute to targeted care by physical therapists and multiprofessional teams and the implementation of early assessments and interventions, particularly for individuals at risk. These data could also benefit administrators of public health services in Brazil, by demonstrating that strengthening rehabilitation teams in hospital settings will contribute to improving care and lowering healthcare costs, because it promotes functional independence in older adults after discharge when they return to the community.

Limitations of the study were that the research data pertained to older adults with good functional status at admission, admitted to only two inpatient units at a public hospital in the DF, Brazil, and that data on functional capacity at discharge were collected by telephone, in some cases provided by caregivers. The sample size in the present study may have been underestimated, which may have contributed to the low power in some analyses, thus requiring caution when interpreting the results. Future studies should increase the sample size and number of collection sites and devise different strategies for assessing functional capacity at discharge by obtaining a direct report from older adults. Strengths were that participants were not selected based on specific health conditions, favoring generalization of the results, and those who died were not included in the functional decline group. Additionally, all the tools used to collect data exhibit moderate to high validity and reliability.17,18,24,25

In Brazilian older adults, physical performance on admission was related to functional capacity at discharge, indicating that hospitalization contributes to a significant reduction in functional capacity. Physical performance in HGS and the SPPB can be used to screen for older adults at risk of reduced functional capacity for BADLs. These findings reinforce the importance of implementing physical performance assessment measures in hospitalized older adults, making it possible to identify those at risk of functional decline and favoring the adoption of patient care intervention by multidisciplinary teams to minimize this decline.