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Home > RNJ > 2008 > July/August > Predicting Posthospital Recovery of Physical Function Among Older Adults After Lower Extremity Surgery in a Short-Stay Skilled Nursing Facility

Predicting Posthospital Recovery of Physical Function Among Older Adults After Lower Extremity Surgery in a Short-Stay Skilled Nursing Facility
Jia Lee, PhD RN Patricia A. Higgins, PhD RN

This study describes the posthospital recovery of physical function among 131 older adults after lower extremity surgery in a short-stay skilled nursing facility (SNF), and identifies admission factors predicting physical function at discharge. Multiple regression analyses found that older adults with low baseline physical function, pressure ulcer, malnutrition, memory loss upon admission, and not enough physical therapy had poor physical function at the time of discharge from the facility. This study generated the following recommendations for nurses working in short-stay SNFs: (1) screen all posthospital residents at admission with predictors to identify people at risk for physical functional decline, (2) design and implement targeted nursing and rehabilitation interventions to improve physical function, and (3) develop discharge plans that provide ongoing monitoring and interventions for community or nursing home nurses.

The number of elderly Americans with physical impairments is significantly increasing. Fifty-seven percent of elderly people have a condition that limits their physical mobility (AARP, 2003). Physical functional decline is a major concern for older adults, especially those who are discharged from acute care hospitals. Typically, postsurgical elders transfer from acute care hospitals to short-stay skilled nursing facilities (SNFs) or rehabilitation centers for intensive rehabilitation therapy; they subsequently are discharged home or to long-term care (LTC) facilities. This immediate posthospital period represents a crucial window during which older adults are challenged to regain functional independence. But postsurgical older adults who have lower extremity surgery demonstrate a pattern of persistent physical functional decline. Consequently, it is important to understand the factors that influence posthospital recovery of physical function and ways to improve or maintain physical function with targeted interventions.

This study was conducted to identify the pattern of change in physical function among posthospital elderly patients after lower extremity surgery who may have admission factors that predict physical function at discharge in a short-stay SNF. Identifying risk factors early may help to develop targeted interventions for older adults at risk of losing physical function during the posthospital recovery period.

Conceptual Model

Previous studies were reviewed using combinations of the following key words from CINAHL, MEDLINE, PubMed, and PsycINFO: change in physical function, elderly, factors, function, functional decline, hospital, nursing home, older adults, physical function, predicting, predictors, recovery, and skilled nursing facility. In total, 56 studies were collected; after analyzing abstracts, the review was narrowed to 20 relevant studies. The literature review identified nine predictive variables: poor baseline physical function, pressure ulcer, urinary incontinence, malnutrition, pain, history of falls, cognitive impairment, negative mood state, and rehabilitation therapy (Figure 1). The dependent variable was physical function at discharge from the SNF. Age and comorbidity were controlled as covariates.

Admission Factors

Baseline physical function was the strongest predictor of future physical function in elderly patients, particularly after acute medical illness such as respiratory tract infection or hip fracture (Binder et al., 2003; Lee, 2006; Marottoli, Berkman, & Cooney, 1992; Sager et al., 1996).

Approximately 23% of patients living in skilled care facilities or nursing homes developed pressure ulcers, which are predictive of declines in activities of daily living (ADLs) or delayed recovery of premorbid function (Binder et al., 2003; Johnson, Kramer, Lin, Kowalsky, & Steiner, 2000). Urinary incontinence affects more than 50% of elders in hospitals and LTC facilities (AHCPR, 1996; Mezey & Fulmer, 1999). ADL scores are strongly associated with incontinence (Burgio, Ives, Locher, Arena, & Kuller, 1994). Malnutrition affects 40%–62% of patients in hospitals, and 40%–80% of those in nursing homes (Abbasi & Rudman, 1993; Constans et al., 1992; Guigoz, Vellas, & Garry, 1996; Morley & Kraenzle, 1994; Saletti, Johansson, & Cederholm, 1999). Deteriorating functional status is associated with albumin levels, subscapular skinfold thickness, and decreasing body cell mass in nursing home residents (Zuliani et al., 2001).

Pain is a common problem that can influence the physical function of elderly people (Ferrell, 1991). Pain of severe-or-greater intensity was significantly associated with physical disability in 885 community-dwelling older adults (Scudds & Robertson, 2000). One of three older adults falls each year (Hausdorff, Rios, & Edelber, 2001). Among those with a history of falls, 20%–30% sustain moderate-to-severe injuries that reduce mobility and independence and increase the risk of premature death (Alexander, Rivara, & Wolf, 1992; Fox et al., 2000; Karlsson et al., 1996).

Cognitive impairment is relatively common in the elderly, with an estimated 4–5 million older adults experiencing cognitive disorders such as acute confusion, delirium, and dementia (Mezey & Fulmer, 1999). Poor cognitive capacity was one of the most consistent and significant predictors of functional impairment, particularly the ability to perform instrumental activities of daily living (IADLs; Laukkanen, Kauppinen, Era, & Heikkinen, 1993). (IADLs are daily tasks such as grocery shopping that enable patients to live independently in the community.) Negative mood state is defined as feelings of depression, anxiety, and sadness (Gowans et al., 2001). In a prospective cohort study of 120 community-dwelling older adults who had a hip fracture during a 6-year study period, depression was a significant factor in functional recovery (Marottoli et al., 1992).

Interventions

Rehabilitation Therapy

In posthospital intensive rehabilitation, older adults who have had lower extremity surgery benefit from the comprehensive, integrated efforts of a number of professional disciplines working to increase patients’ extremity strength and endurance and improve standing balance and ADL tolerance (Brummel-Smith, 1993). Physical therapists primarily work toward improving patients’ range of motion, strength, endurance, balance, and mobility (Clark & Bray, 1984). Occupational therapists work to improve patients’ upper extremity function and self-care abilities to perform ADLs (Clark & Bray).

Covariates

Age

Physical functional decline becomes more prevalent with age (Binder et al., 2003). Twenty percent of people over age 65 require assistance with ADLs, and 45% of people older than age 85 require such assistance; difficulty with IADLs also increases with age (Mezey & Fulmer, 1999). Age may not directly influence physical functional decline; however, it may accelerate the effects of other risk factors on change in physical function.

Comorbidity

Severe comorbid conditions decrease functional autonomy (Di Libero, Fargnoli, Pittiglio, Mascio, & Giaquinto, 2001). A prospective cohort study of 367 older people with hip fracture found that higher levels of comorbidity were associated with increased risk of functional dependence (Cree, Carriere, Soskolne, & Suarez-Almazor, 2001). Comorbidity may affect study outcomes, either independently or by confounding the effect of treatment or primary disease (Nitz, 1997).

Method

Design

This study employed a retrospective cohort design with a series of admissions to a short-stay SNF from an acute care hospital. All subjects were admitted after having lower extremity surgery, and data were abstracted from patients’ medical records and the Minimum Data Set (MDS) 2.0.

Setting and Participants

The study was approved by the institutional review board at the university hospital system in an urban Midwest area. The medical records of all residents admitted to a short-stay SNF were reviewed to identify study subjects. The nursing facility had a 100-bed subacute care unit and administrative and rehabilitation areas. Most residents living in this facility had transferred from acute care hospitals.

The sample size of 131 elderly patients was determined by a power of .80, alpha level of .05, moderate effect size of R2 = .13, and 11 independent variables for multiple regression (Cohen, West, Cohen, & Aiken, 2003). No previously published research examining physical function in short-stay SNFs existed using the proposed predictive variables; to calculate the sample size, the moderate effect size of R2 = .13 was used for the multiple regression test.

Medical records of consecutive posthospital elderly patients were reviewed from a short-stay SNF at an urban academic medical center in the Midwest between January 2000 and December 2002. Sample inclusion criteria were appropriate age (65 or older) and admission from an acute care hospital immediately after lower extremity surgery (total hip replacement, total knee replacement, or open reduction and internal fixation of hip). The exclusion criterion was severe cognitive impairment, indicated by an MDS Cognitive Performance Scale (CPS) score of 5 or higher (Morris et al., 1994). The CPS measures consist of memory impairment and levels of consciousness and executive function, with scores ranging from 0 (intact) to 6 (very severe impairment). It demonstrates substantial agreement with the Mini-Mental Status Exam (MMSE) in identifying cognitive impairment; the sensitivity was .94 (95% CI, .87, .96) and the specificity was .94 (95% CI, .88, 1.0; Hartmaier et al., 1995).

Measures

Baseline Physical Function

Because the MDS-ADL assessment was done only on facility admission, motor subtotal scores of the Functional Independence Measure (motor-FIM) from rehabilitation notes were used to measure physical function on admission and at discharge to determine the degree of recovery during the facility stay. The facility used recoded scores of the original motor-FIM. If function improves in the original tool, motor-FIM scores go up. But if function improves in the facility, motor-FIM scores go down. For analysis, the facility’s recoded motor-FIM scores were again recoded. In this study, if there was an improvement in function, motor-FIM scores would go up as the original FIM scoring system. The 13-item motor-FIM consists of six items for self-care, two items for sphincter control, three items for mobility, and two items for locomotion, and ratings range from 1 (total assist) to 7 (complete independence). The intraclass correlation coefficient was .92 in 73 stroke survivors (Daving, Andren, Nordholm, & Grimby, 2001).

Pressure ulcer was measured with the MDS Skin Condition Scale, which tallies the number of ulcers at each ulcer stage and types of ulcers. The total score was summed after multiplying the number of ulcers by the staging scores of each (Berlowitz et al., 2001). In a comparison study, the MDS predicted 62 of 66 pressure ulcers, while the Braden Scale predicted only 46 pressure ulcers accurately (Vap & Dunaye, 2000). Urinary incontinence was evaluated with the MDS Bladder Continence Scale, which assesses control of urinary bladder function with appliances (e.g., a Foley catheter) or continence programs. Malnutrition was measured using the two MDS nutrition items: weight loss (≥5% during the previous 30 days, or ≥10% during the previous 180 days) or weight gain (≥5% in the last 30 days, or ≥10% in the last 180 days). Pain was measured with the MDS Pain Scale and was coded from “mild” to “horrible.” In a study of 95 postacute nursing home residents, there was agreement (93%) between the MDS and the visual analogue scale measures of pain (Fries, Simon, Morris, Flodstrom, & Bookstein, 2001). History of falls was measured with the 2-item MDS Health Conditions-Accidents Scale, which assesses for falls in the past 30 days or falls in the past 31–180 days.

Cognitive impairment was measured using the MDS Cognitive Scale, which measures long- and short-term memory loss and memory recall ability. The criterion-related validity (construct validity) of the scale showed strong correlations with the MMSE (r = .75, p < .001) in a study of 290 nursing home residents (Cohen-Mansfield, Taylor, McConnell, & Horton, 1999). Negative mood state was measured by the 16 MDS mood items, which were found to have good agreement with the Geriatric Depression Scale Short Form (Kappa = .60, p < .01; Schnelle, Wood, Schnelle, & Simmons, 2001).

Demographic data included admission diagnoses, age, gender, race, length of stay, comorbidity, and type of surgery. Comorbidity was measured by the Charlson Comorbidity Index (CCI; Charlson, Pompei, Ales, & MacKenzie, 1987). The CCI is widely used to capture the number and severity of health problems present and is easily completed using medical records in acute units and in LTC settings (Bravo, Dubois, Hebert, De Wals, & Messier, 2002; Charlson et al.). The CCI consists of 45 items corresponding to four levels of disease conditions. Based on previous findings, age and comorbidity were controlled as covariates (Administration on Aging, 2004; Bravo et al.; Di Libero et al., 2001; Kempen, Brilman, Ranchor, & Ormel, 1999). Rehabilitation therapy included physical therapy (PT) and occupational therapy (OT). This cohort received 6 days of PT and 5 days of OT every week. The amount of rehabilitation therapy for analysis was the mean of total minutes of rehabilitation therapy per day that a patient received while in the facility. Researchers counted total minutes of PT or OT and divided them by actual days patients received PT or OT.

Results

Characteristics and Patterns of Change in Physical Function

Older adults ranged in age from 66 to 95 years, with a mean of 77.1 years (SD = 6.9; see Table 1). The majority of subjects were women (n = 98, 75%), unmarried (n = 82, 64%), and White (n = 92, 70%). The mean length of stay was 18.7 days (SD = 4.4, range = 15–44). Among this sample, 108 subjects (82%) were discharged to home and 23 (18%) went to a nursing home. Residents discharged to nursing homes were significantly older, had more pressure ulcer episodes and cognitive impairment, and were more depressed at the time of facility admission. The mean physical function score on admission was 46.4 (SD = 8.3, range = 19–69) in the motor-FIM. The motor-FIM on admission and at discharge had high Cronbach’s alpha reliability (a = .81, and a = .87, respectively). Physical function significantly improved during the facility stay, increasing from 46.4 to 71.4 (p < .0001) in the motor-FIM.

Overwhelmingly (99%, n = 130), older adults reported pain on admission that was mild (n = 8), moderate (n = 84), and severe (n = 38; Figure 2). Thirty-one percent of residents (n = 42) had a history of falls on admission. Among those who had fallen (n = 11), 26% had surgery resulting from fall fractures: hip fractures were the most common (n = 6), followed by femoral fractures (n = 3), pelvic fracture (n = 1), and tibia fracture (n = 1). No subject fell during his or her facility stay.

Thirty-four older adults (26%) had pressure ulcers, including eight residents with multiple-stage ulcers and 20 residents with multiple lesions at stage I (n = 9), stage II (n = 29), stage III (n = 1), and stage IV (n = 4). Twenty percent (n = 25) of subjects reported urinary incontinence on admission as occasional (n = 12), frequent (n = 10), or always incontinent (n = 3). Sixteen percent (n = 21) experienced memory loss characterized as short term (n = 17), long term (n = 1), or both (n = 3), while 90% (n = 117) reported no problems with recall ability. Consequently, memory loss was used only in analysis. Twelve percent (n = 16) had weight fluctuations or weight gain (n = 10) or weight loss (n = 6). Mood problems were reported in 44% (n = 58) of cases, but items checked were limited to 1 or 2 of the 16 criteria, such as insomnia/change in usual sleep pattern or sad, pained, worried facial expressions.

Predicting Physical Function at Discharge

Hierarchical multiple regression examined two models (Table 2). One model used only the co- variates of age, comorbidity, and baseline physical function because it was expected they would have the strongest impact on physical function at discharge. The multiple R2 for this model was 0.42, with baseline physical function as a strongest predictor (B = .58, p < .0001). Age or comorbidity was not significant in predicting physical function at discharge. The second model included other admission factors of interest and rehabilitation therapy as described above. In this case, the multiple R2 increased to 0.55. Among the independent variables, pressure ulcer, malnutrition, memory loss, and rehabilitation therapy all had coefficients that were significantly different from 0. Because the coefficients of the admission variables all were negative, this would correspond to lower motor-FIM scores and worse outcomes. The sign of the coefficient for rehabilitation therapy is positive, meaning that more rehabilitation therapy is predicted to result in better physical function at discharge among posthospital older adults after lower extremity surgery.

Discussion

The study described the pattern of posthospital recovery of physical function and its admission predictors among older adults after lower extremity surgery in a short-stay SNF. Residents receiving intensive rehabilitation therapy experienced improved physical function after an average stay of 19 days at the facility. Approximately 80% of the subjects returned home and 20% were transferred to an LTC facility. The leading primary causes of falls are gait and balance disturbances related to decline in physical function and environmental hazards (American Geriatrics Society Panel on Falls Prevention, 2001). Greater emphasis on fall prevention for residents with histories of falls or for those at risk for falls will reduce LTC admissions.

The older adults who participated in this study and had poor physical function, pressure ulcer, malnutrition, and memory loss upon admission to a short-stay SNF had poor physical function at SNF discharge. Older adults with these problems need targeted interventions to improve their physical function. Consistent with previous studies (Marottoli et al., 1992; Sager et al., 1996), baseline physical function on admission was the strongest predictor of physical function at discharge in this cohort. Alternative types or greater intensity of rehabilitation therapies may be necessary for those experiencing the lowest levels of physical function upon SNF admission to help them prepare more adequately for discharge.

Among this study’s participants, 26% had pressure ulcers at the time of admission to the short-stay SNF. The more severe the ulcers, the more likely the residents would be dependent in physical function at discharge. This finding is consistent with previous studies that found an inverse relationship between pressure ulcer at rehabilitation admission and physical function at discharge or recovery of premorbid function (Binder et al., 2003; Johnson et al., 2000).

Malnutrition was associated with dependence in physical function at discharge. Interestingly, weight gain as well as weight loss was highly predictive of dependence in physical function at discharge. Although the data in the MDS do not detail the cause of weight fluctuation, 10 residents had congestive heart failure as an admission diagnosis. Weight fluctuation may be an important indicator of patient health that requires further assessment to understand its underlying causes.

Elderly patients with memory loss at admission reported relatively lower physical function at discharge. These results are congruent with previous studies (Chiodo, Kanten, Gerety, & Mulrow, 1994; Sager et al., 1996) and are notable because the inclusion criteria for this study excluded older adults with severe cognitive impairment.

This study’s findings generated several clinical practice recommendations for nurses working in short-stay SNFs. First, nurses should screen all posthospital residents at admission with predictors that help identify people at risk of physical functional decline. Nurses also should design and implement targeted nursing interventions and rehabilitation interventions to improve physical function.

If nurses can identify a person with pressure ulcer, urinary incontinence, and cognitive impairment at admission, for example, they can expect this resident will have a longer stay because of their increased potential for physical functional decline or delayed recovery. Nurses should compose a plan for these patients’ long-term care and provide targeted interventions based on prioritized assessments of indicators of physical functional decline. Nurses also should develop discharge plans that provide ongoing monitoring and interventions for community-based or LTC nurses. They must develop standard discharge plans and protocols of institutional communication among facilities to provide consistent, ongoing care to patients who receive care from short-term SNFs, home care agencies, or LTC facilities.

This study has several methodological weaknesses. Regional variations could not be addressed because the study was conducted at one particular facility (an academic medical center). Measures of this study’s variables relied on the accuracy of MDS data collection. Although a trained clinician conducted this multidimensional assessment and many of the items use objective criteria, the assessment also includes a more subjective appraisal of client health, such as mood and behavior patterns. In addition, memory loss from the MDS cognition items (memory loss and memory recall ability) was used for the analysis because 90% of this study sample reported no problems with recall ability. However, memory represents only a small portion of cognition, and participants might have retained other aspects of cognition. Lastly, this was a retrospective study that relied on limited data contained in medical records.

Despite its methodological weaknesses, this study shows that admission factors can predict post- hospital recovery of physical function in short-stay SNFs. As shortened hospital stays increase the likelihood of discharge complications including physical functional decline in vulnerable older adults, patterns of posthospital recovery of physical function need to be investigated. The study’s findings will contribute to more effective nursing care planning and further research on posthospital recovery of physical function.

About the Authors

Jia Lee, PhD RN, is an assistant professor at Kyung Hee University in Seoul, South Korea. Address correspondence to her at leejia@khu.ac.kr.

Patricia A. Higgins, PhD RN, is an associate professor at Frances Payne Bolton School of Nursing, Case Western Reserve University in Cleveland, OH.

References

AARP. (2003). Beyond 50.03: A report to the nation on independent living and disability. Washington, DC: Author.

American Association of Colleges of Nursing & John A. Hartford Foundation Institute for Geriatric Nursing. (2000). Older adults: Recommended baccalaureate competencies and curricular guidelines for geriatric nursing care. Retrieved May 21, 2008, from http://www.aacn.nche.edu/Education/pdf/Gercomp.pdf.

Abbasi, A. A., & Rudman, D. (1993). Observations on the prevalence of protein-calorie undernutrition in VA nursing homes. Journal of the American Geriatrics Society, 41, 117–121.

Administration on Aging. A profile of older Americans: 2004. Retrieved March 31, 2008, from www.aoa.gov/prof/Statistics/profile/2004/3.asp.

AHCPR (1996). Urinary incontinence in adults: Acute and chronic management, clinical practice guideline No. 2. Rockville, MD: AHCPR.

American Geriatrics Society Panel on Falls Prevention. (2001). Guideline for the prevention of falls in older persons: American Geriatrics Society, British Geriatrics Society, American Academy of Orthopaedic Surgeons Panel on Falls Prevention. Journal of the American Geriatric Society, 49, 664–672.

Alexander, B. H., Rivara, F. P., & Wolf, M. E. (1992). The cost and frequency of hospitalization for fall-related injuries in older adults. American Journal of Public Health, 82, 1020–1023.

Berlowitz, D. R., Brandeis, G. H., Anderson, J. J., Ash, A. S., Kader, B., Morris, J. N., et al. (2001). Evaluation of a risk-adjustment model for pressure ulcer development using the minimum data set. Journal of the American Geriatrics Society, 49, 872–876.

Binder, E. F., Kruse, R. L., Sherman, A. K., Madsen, R., Zweig, S. C., D’Agostino, R., et al. (2003). Predictors of short-term functional decline in survivors of nursing home-acquired lower respiratory tract infection. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 58(1), 60–67.

Bravo, G., Dubois, M. F., Hebert, R., De Wals, P., & Messier, L. (2002). A prospective evaluation of the Charlson Comorbidity Index for use in long-term care patients. Journal of the American Geriatrics Society, 50, 740–745.

Brummel-Smith, K. (1993). Research in rehabilitation. Clinics in Geriatric Medicine, 9, 895–904.

Burgio, K. L., Ives, D. G., Locher, J. L., Arena, V. C., & Kuller, L. H. (1994). Treatment seeking for urinary incontinence in older adults. Journal of the American Geriatric Society, 42, 208–212.

Charlson, M. E., Pompei, P., Ales, K. L., & MacKenzie, C. R. (1987). A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. Journal of Chronic Disease, 40, 373–383.

Chiodo, L. K., Kanten, D. N., Gerety, M. B., & Mulrow, C. D. (1994). Functional status of Mexican American nursing home residents. Journal of the American Geriatrics Society, 42, 293–296.

Clark, G. S., & Bray, G. P. (1984). Development of a rehabilitation plan. In T. F. Williams (Ed.), Rehabilitation in the aging (pp. 125–143). New York: Raven Press.

Cohen, J., West, S. G., Cohen, P., & Aiken, L. (2003). Applied multiple regression/correlation analysis for the behavioral sciences (3rd ed.). Mahwah, NJ: Lawrence Erlbaum Associates, Inc.

Cohen-Mansfield, J., Taylor, L., McConnell, D., & Horton, D. (1999). Estimating the cognitive ability of nursing home residents from the Minimum Data Set. Outcomes Management for Nursing Practice, 3, 43–46.

Constans, T., Bacq, Y., Brechot, J. F., Guilmot, J. L., Choutet, P., & Lamisse, F. (1992). Protein-energy malnutrition in elderly medical patients. Journal of the American Geriatrics Society, 40, 263–268.

Cree, M., Carriere, K. C., Soskolne, C. L., & Suarez-Almazor, M. (2001). Functional dependence after hip fracture. American Journal of Physical Medicine and Rehabilitation, 80, 736–743.

Daving, Y., Andren, E., Nordholm, L., & Grimby, G. (2001). Reliability of an interview approach to the Functional Independence Measure. Clinical Rehabilitation, 15, 301–310.

Di Libero, F., Fargnoli, M., Pittiglio, S., Mascio, M., & Giaquinto, S. (2001). Comorbidity and rehabilitation. Archives of Gerontology and Geriatrics, 32, 15–22.

Ferrell, B. A. (1991). Pain management in elderly people. Journal of the American Geriatrics Society, 39, 64–73.

Fox, K. M., Magaziner, J., Hawkes, W. G., Yu-Yahiro, J., Hebel, J. R., Zimmerman, S. I. et al. (2000). Loss of bone density and lean body mass after hip fracture. Osteoporosis International, 11, 31–35.

Fries, B. E., Simon, S. E., Morris, J. N., Flodstrom, C., & Bookstein, F. L. (2001). Pain in U.S. nursing homes: Validating a pain scale for the minimum data set. Gerontologist, 41, 173–179.

Gowans, S. E., deHueck, A., Voss, S., Silaj, A., Abbey, S. E., & Reynolds, W. J. (2001). Effect of a randomized controlled trial of exercise on mood and physical function in individuals with fibromyalgia. Arthritis and Rheumatism, 46, 519–529.

Guigoz, Y., Vellas, B., & Garry, P. J. (1996). Assessing the nutritional status of the elderly: The Mini Nutritional Assessment as part of the geriatric evaluation. Nutrition Reviews, 54, S59–S65.

Hartmaier, S. L., Sloane, P. D., Guess, H. A., Koch, G. G., Mitchell, C. M., & Phillips, C. D. (1995). Validation of the Minimum Data Set Cognitive Performance Scale: Agreement with the Mini-Mental State Examination. Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 50, M128–M133.

Hausdorff, J. M., Rios, D. A., & Edelber, H. K. (2001). Gait variability and fall risk in community-living older adults: A 1-year prospective study. Archives of Physical Medicine and Rehabilitation, 82, 1050–1056.

Johnson, M. F., Kramer, A. M., Lin, M. K., Kowalsky, J. C., & Steiner, J. F. (2000). Outcomes of older persons receiving rehabilitation for medical and surgical conditions compared with hip fracture and stroke. Journal of the American Geriatrics Society, 48, 1389–1397.

Karlsson, M., Nilsson, J. A., Sernbo, I., Redlund-Johnell, I., Johnell, O., & Obrant, K. J. (1996). Changes of bone mineral mass and soft tissue composition after hip fracture. Bone, 18, 19–22.

Kempen, G. I., Brilman, E. I., Ranchor, A. V., & Ormel, J. (1999). Morbidity and quality of life and the moderating effects of level of education in the elderly. Social Science & Medicine, 49, 143–149.

Laukkanen, P., Kauppinen, M., Era, P., & Heikkinen, E. (1993). Factors related to coping with physical and instrumental activities of daily living among people born in 1904–1923. International Journal of Geriatric Psychiatry, 8, 287–296.

Lee, J. (2006). An imperative to improve discharge planning: Predictors of physical function among residents of a Medicare skilled nursing facility. Nursing Administration Quarterly, 30, 38–47.

Marottoli, R. A., Berkman, L. F., & Cooney, L. M., Jr. (1992). Decline in physical function following hip fracture. Journal of the American Geriatrics Society, 40, 861–866.

Morley, J. E., & Kraenzle, D. (1994). Causes of weight loss in a community nursing home. Journal of the American Geriatrics Society, 42, 583–585.

Morris, J. N., Fries, B., Mehr, D. R., Hawes, C., Phillips, C., Mor, V., et al. (1994). MDS Cognitive Performance Scale. Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 49, M174–M182.

Nitz, N. M. (1997). Comorbidity. In R. L. Kane (Ed.), Understanding health care outcomes research (pp. 153–174). Gaithersburg, MA: Aspen.

Sager, M. A., Rudberg, M. A., Jalaluddin, M., Franke, T., Inouye, S. K., Landefeld, C. S. et al. (1996). Hospital admission risk profile (HARP): Identifying older patients at risk for functional decline following acute medical illness and hospitalization. Journal of the American Geriatrics Society, 44, 251–257.

Saletti, A., Johansson, L., & Cederholm, T. (1999). Mini Nutritional Assessment in elderly subjects receiving home nursing care. Journal of Human Nutrition and Dietetics, 12, 381–387.

Schnelle, J. F., Wood, S., Schnelle, E. R., & Simmons, S. F. (2001). Measurement sensitivity and the Minimum Data Set depression quality indicator. Gerontologist, 41, 401–405.

Scudds, R. J., & Robertson, J. M. (2000). Pain factors associated with physical disability in a sample of community-dwelling senior citizens. Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 55A, M393–M399.

Vap, P. W., & Dunaye, T. (2000). Pressure ulcer risk assessment in long-term care nursing. Journal of Gerontological Nursing, 26, 37–45.

Zuliani, G., Romagnoni, F., Volpato, S., Soattin, L., Leoci, V., Bollini, M. C., et al. (2001). Nutritional parameters, body composition, and progression of disability in older disabled residents living in nursing homes. Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 56, M212–M216.