Unintended Weight Loss in Older Adults

UWL: Screening and Assessment Methods (2009)

Citation:

Murphy MC, Brooks CN, New SA, Lumbers ML. The use of the Mini-Nutritional Assessment (MNA) tool in elderly orthopaedic patients. European Journal of Clinical Nutrition, 2000; 54: 555-562.

PubMed ID: 10918465
 
Study Design:
Observational study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To assess the use of the Mini-Nutritional Assessment (MNA) in elderly orthopaedic patients. The project was designed to:

  • Assess the new version of the MNA and determine the sensitivity and specificity of the classification of elderly patients
  • Assess the comparability of the MNA with more traditional assessments of nutritional status, including current dietary intake, biochemical and anthropometric measurements.
Inclusion Criteria:
  • All patients over 60 years of age admitted for emergency surgery for a fractured neck of femur or elective surgery for a total hip replacement were approached and asked if they would be willing to take part in the study
  • Patients who agreed to participate were assessed using the Abbbreviated Mental Test (AMT).
Exclusion Criteria:

Patients with mental impairment (as judged by a score of less than four on the Abbreviated Mental Test), in whom informed consent or reliable communication was not possible.

Description of Study Protocol:

Recruitment

All patients aged over 60 years admitted for emergency surgery for a fractured neck of femur or elective surgery for a total hip replacement were approached and asked if they would be willing to take part in the study.  Patients who agreed to participate were assessed using the Abbbreviated Mental Test (AMT).

Design

Observational study.

Statistical Analysis

  • Statistical analysis of the data involved examination of the classification of patients with the MNA (screening and the full examination) to establish whether the malnourished, at-risk and well-nourished were discrete groups and whether there were any significant differences in nutritional intake, anthropometric and biochemical data between them
  • Anthropometric and biochemical data were analyzed using one-way ANOVA followed by a Tukey multiple-comparisons test to locate the differences
  • Dietary data was analyzed by the non-parametric Mann-Whitney U-test
  • Association between the data was analyzed by Pearson's test for correlations
  • Stepwise linear multiple-regression analysis was used to identify the questions in the MNA which best predicted the MNA total and the screening score
  • Sensitivity and specificity were examined to assess whether the risk scores are associated with other indices of nutritional assessment.
Data Collection Summary:

Timing of Measurements

All measurements made after surgery, on Day Five of their hospital stay.

Dependent Variables

  • Mini-Nutritional Assessment (MNA) questionnaire
  • Anthropometry (weight, height, mid-upper arm and calf circumferences, demispan)
  • Blood samples analyzed for plasma albumin, transferrin and C-reactive protein levels
  • Current nutritional intake of subjects assessed, starting on Day Five after surgery, by carrying out three consecutive 24-hour recalls using the hospital menu cards as prompts to aid accurate recall.

Independent Variables

Post-orthopedic surgery.

Description of Actual Data Sample:
  • Initial N: 49 female patients. 41 had dietary records and 36 gave a blood sample for biochemical analysis.
  • Attrition (final N): As above
  • Age: Aged 60 to 103 years; mean, 79.5 years
  • Ethnicity: Not mentioned
  • Other relevant demographics: 42 patients had emergency admission for fractured neck of femur. Seven patients had elective surgery for total hip replacement.
  • Location: Royal Surrey County Hospital, United Kingdom.
Summary of Results:

Questions in the MNA Which Significantly Predicted the Total Score

MNA Question

Descriptor Adjusted R2 Values (%) P-Value

F

BMI rating
53.5

0.001

B

Weight loss over the previous three months

9.9

0.001

C Mobility rating
2.7
0.003
O Self-view of nutritional status
4.1
0.004
J Number of meals eaten per day
3.5
0.007
E Neuropsychological problems
1.9
0.049

Other Findings

  • The group as a whole had low mean values for body weight, albumin and transferrin and high CRP levels
  • In addition, the group had mean energy intakes well below the estimated average requirement (EAR) and mean intakes of vitamin D, magnesium, potassium, selenium and non-starch polysaccharides were below the lower reference nutrient intakes
  • The MNA screening section categorized 69% of the patients as requiring a full assessment (scored 11 or below), but for the purposes of the study, the MNA was completed on all patients
  • The MNA assessment categorized 16% of the group as "malnourished" (N=8, scored less than 17 points), 47% as "at risk" (N=23, scored 17.5 to 23.5) and 37% as "well nourished" (N=18, scored over 23.5)
  • Significant differences were found between the malnourished and well nourished groups for body weight (P<0.001), body mass index (P<0.001), demiquet (P<0.001) and mindex (P<0.001)
  • Mean values for energy and nutrient intakes showed a clear stepwise increase across the three groups for all nutrients except sodium, with significant differences for protein (P<0.05), carbohydrate (P<0.05), riboflavin (P<0.05), niacin (P<0.05), pyridoxine (P<0.05), folate (P<0.05), calcium (P<0.05), selenium (P<0.05), iron (P<0.05) and non-starch polysaccharides (P<0.05) intakes
  • Stepwise multiple regression analysis indicated that anthropometric assessments were the most predictive factors in the total MNA score
  • The sensitivity and specificity of the MNA was assessed in comparison with albumin levels, energy intake and mindex
  • The sensitivity of the MNA classification of those scoring less than 17 points, in comparison with albumin levels, energy intake and mindex, varied from 27% to 57% and the specificity was 66% to 100%
  • This was compared with the sensitivity and specificity of using a score of less than 23.5 on the MNA to predict malnourished individuals
  • Using this cut-off, the sensitivity ranged from 75% to 100%, but the specificity declined to between 37% and 50%.
Author Conclusion:

These data suggest that the MNA is a useful diagnostic tool for the identification of elderly patients at risk from malnutrition and those who are already malnourished in this hospital setting. However, further studies are required to determine whether it is effective as a tool for monitoring response to treatment, such as nutritional support.

Funding Source:
Industry:
Reviewer Comments:
  • Small sample size
  • Measurements not completed in all subjects
  • Authors note that the small number of subjects in each category suggests that caution should be used when interpreting the results.
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) N/A
  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) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? 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
  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) N/A
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? ???
2. Was the selection of study subjects/patients free from bias? ???
  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
  2.1. 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
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? 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? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  3. Were study groups comparable? ???
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? ???
  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? ???
  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.) ???
  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.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
  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. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? 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
  4.2. 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
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.4. 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
  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? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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.) Yes
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  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
  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? Yes
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? 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? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? 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
  6.4. 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
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments 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
  6.7. 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
  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. 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
  7.1. 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
  7.2. 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
  7.3. 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
  7.4. 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
  7.5. 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
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? 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. 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
  8.1. 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
  8.2. 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
  8.3. 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
  8.4. 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
  8.5. 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
  8.6. 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
  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. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  10. Is bias due to study's funding or sponsorship unlikely? ???
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? ???
  10.2. Was the study free from apparent conflict of interest? ???