Unintended Weight Loss in Older Adults

UWL: Screening and Assessment Methods (2009)

Citation:

Neumann SA, Miller MD, Daniels L, Crotty M. Nutritional status and clinical outcomes of older patients in rehabilitation. Journal of Human Nutrition and Dietetics. 2005; 18(2): 129-136.

PubMed ID: 15788022
 
Study Design:
Prospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

Aims of the study were:

  • To assess the nutritional status of older patients on admission to rehabilitation using the Mini Nutrition Assessment (MNA), body mass index (BMI) and corrected arm muscle area (CAMA)
  • To determine the predictive value of these indicators of nutritional status on relevant clinical outcomes, including length of rehabilitation stay, admission to higher level care, physical function and quality of life. 
Inclusion Criteria:

All patients admitted for inpatient rehabilitation from April 2003 to July 2003.

Exclusion Criteria:
  • Less than 65 years of age
  • Inability to provide informed consent
  • Terminal illness
  • Medically unstable
  • Not recruited within four days of admission
  • Previously admitted during the study period.
Description of Study Protocol:

Recruitment

All admissions for inpatient rehabilitation from April 2003 to July 2003 were considered for participation.

Design

Prospective cohort study. Measurements of nutritional assessment with clinical outcomes abstracted from medical records following discharge. 

Statistical Analysis

  • The chi-square test of association and T-tests were used to compare demographic characteristics (age, gender, marital status, pre-admission accommodation, diagnosis and length of acute hospitalization) of those who did and did not participate
  • The chi-square test of association was used to determine the likelihood of discrete outcomes based on admission nutrition status scores and the Mann-Whitney U test was used to compare nutrition status on admission with length of stay.   
Data Collection Summary:

Timing of Measurements

Nutritional status was assessed within the first four days of admission and outcomes measures following discharge were assessed.

Dependent Variables

  • Length of rehabilitation stay (days)
  • Admission to higher level of care (from medical record notes)
  • Dietetic input
  • Physical function using the modified Barthel index (MBI) at admission and after 90 days
  • Quality of life on admission and after 90 days using the assessment of quality of life (AQoL).

Independent Variables

Nutritional status on admission as measured by Mini Nutritional Assessment, BMI and Corrected Arm Muscle Area.

 

 

Description of Actual Data Sample:
  • Initial N: 133 subjects (75 female, 58 male)
  • Attrition (final N): 133 subjects
  • Age: 81±6 years
  • Other relevant demographics: N=52 (39%) married; N=81 (61%) lived alone
  • Location: Rehabilitation hospital in South Australia.
Summary of Results:

   

Clinical Outcomes (Mean ± SD) of Subjects According to the Reference Values for the Mini Nutrition Assessment (MNA) (Guigoz et al, 1994), Body Mass Index (BMI) (Lipski, 1996) and Corrected Arm Muscle Area (CAMA) (Freidmal, et al, 1985)

 

Nutritional Status Indicator on Admission  

N (%) at Admission

 

Higher-level Care*

 

LOS

N (%) at 90 Days

 

90-day Function

90-day Quality of Life§

 
MNA

<12/14

78 (62)

2.22 (1.02 to 4.82)

19 (13 to 28)

62 (53)

86±18

16±6

 ≥12/14

 50 (38)

 

14 (9 to 21)

 54 (47)

 97±7

 13±5

P

 

 

0.003                  

 

0.001         

0.009

<24/30

71 (53)

2.29 (1.09 to 4.80)

18 (13 to 28)

57 (49)

85±19

17±6

≥24/30

62 (47)

 

14 (9 to 1)       

59 (51)

96±7      

12±5

P

 

<0.05

0.023

 

0.002

0.001

BMI

<22kg/m2

22 (17)

1.6 (0.78 to 3.29)

16 (13 to 22)

18 (16)

79±27     

17±6

 ≥22kg/m2

 111 (83)

 

15 (11 to 26)

 98 (84)

 93±10

14±6

CAMA

<21.4cm2 (males)     

27 (20)

2.07 (1.09 to 3.91)

15 (13 to 25)

21 (18)

82±25

14±6

<21.6cm2 (females)

 

 

 

 

 

 

≥21.4cm2 (males)

106 (80)

 

15 (10 to 24)

95 (82)

93±11

16±6

≥21.6cm2 (females)

 

 

 

 

 

 

 P

 

<0.05

0.465

 

0.017

0.310

*Relative risk (95% CI) according to relative risk ratio analysis.

Median (IQR) rehabilitation length of stay (LOS), difference across groups determined using the Mann-Whitney U-test.

Mean (SD) function measured using the modified Barthel index (MBI) (Shah et  al, 1989); higher scores indicate better physical function (range zero to 100); difference across groups determined using ANCOVA with admission MBI score entered as a covariate.

§Mean (SD) quality of life measured using the Assessment of Quality of Life Instrument (AQoL) (Hawthorne et al, 1999); lower scores indicate better quality of life (range zero to 30); difference across groups determined using ANCOVA with admission AQoL score entered as a covariate.

 
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Other Findings

  • 62 (47%) subjects were well nourished, 63 (47%) at risk of malnutrition and eight (6%) malnourished
  • 22 (17%) and 27 (20%) were below the desirable reference values for BMI and Corrected Arm Muscle Area respectively
  • Subjects at risk of malnutrition/malnourished had longer length of stay (P=0.023) and were more likely to be admitted to higher-level care (P<0.05)
  • These subjects also had poorer function on admission (P<0.001) and 90 days (P=0.002), and quality of life on admissions (P<0.008) and 90 days (P=0.001)
  • Those with low Corrected Arm Muscle Area were twice as likely to be admitted to higher-level care (P<0.05) and had poorer function at 90 days (P=0.017)
  • Using these instruments, the authors found a lower incidence of malnutrition than in other studies in similar settings
  • They also noted that RD intervention was not requested for all malnourished patients. 

 

Author Conclusion:

In conclusion, more than half of the sample were screened as possibly malnourished using the short form MNA, and over half were also assessed as either at risk of malnutrition or malnourished using the total MNA. Both possible malnutrition and risk of malnutrition/malnutrition were associated with poorer clinical outcomes, as were BMI and Corrected Arm Muscle Area. 

Funding Source:
University/Hospital: Flinders University, Repatriation General Hospital, Daw Park, Australia
Reviewer Comments:

Authors note the following limitations:

  • Potential for selection bias, possibly resulting in a healthier, better-nourished study population
  • Short follow-up period also precludes conclusions regarding long-term rehabilitation outcomes.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) Yes
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes