Unintended Weight Loss in Older Adults

UWL: Food, Appetite and Environment (2009)


Milne AC, Potter J, Avenell A. Protein and energy supplementation in elderly people at risk for malnutrition. Cochrane Database Syst Rev 2005; (2): CD003288.

PubMed ID: 15846655
Study Design:
Meta-analysis or Systematic Review
M - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To assess the effects and acceptability of oral dietary supplements, usually in the form of commercial "sip-feeds," on improvement in nutritional status and clinical outcomes in both hospitalized elderly people and elderly people in the community.

Inclusion Criteria:
  • Randomized controlled trials and quasi-randomized controlled trials of oral protein and energy supplementation in older people
  • Trials that had a minimum duration of two weeks, with a minimum duration of intervention of one week
  • Studies with participants with a minimum average age of 65 years
  • Mixed groups of patients, in which some were recovering from cancer and some had been receiving critical care.


Exclusion Criteria:
  • Groups recovering from cancer treatment, in critical care or who may have specific nutritional needs relating to their condition 
  • Studies of dietary advice alone
  • Studies of specially designed immunomodulatory supplements or supplements of specific amino acids
  • Studies of protein-only supplementation.
Description of Study Protocol:


Cochrane Central Register of Controlled Trials (CENTRAL, through Issue 1, 2004), MEDLINE (1966 to March 2004), EMBASE (1980 to March 2004), Healthstar (1975 to March 2001), CINAHL (1982 to March 2004), BIOSIS (1985 to March 2004) and CAB abstracts (1973 to March 2004) were searched. Nutrition journals and reference lists were hand-searched.  Sip-feed manufacturers were contacted. Most recent search was completed in March 2004 and several search strategies were used.


Systematic review.

Blinding Used 

Quality was poorest with regard to blinding. Action to ensure blinding of outcome assessors was reported in only six studies, action to blind participants in 10 studies and blinding of treatment providers was reported in eight studies. 


Two reviewers independently assessed trials before inclusion and independently extracted data and assessed trial quality. Authors of trials were contacted for further information as necessary. 

Statistical Analysis

Data were combined for meta-analysis for dichotomous variables, mortality and number of patients with complications as described in the protocol. For each study, relative risks and 95% confidence limits were calculated. The results were combined using fixed effects models and presented with 95% confidence limits. When there was evidence of heterogeneity, a random effects model was applied. Heterogeneity between comparable trials was explored using the I-squared test using more than 50% as the cutoff for significant heterogeneity. A funnel plot to assess small study bias for mortality data was also done.

Data Collection Summary:

Timing of Measurements

Interventions had to be at least one week in duration. The outcome measurements were evaluated at the last available time point of studies. Short-term outcomes were defined as up to three months, medium-term outcomes as three months to six months and long-term outcomes as more than six months. 

Dependent Variables

  • All-cause mortality
  • Morbidity and number of people with complications
  • Functional status
  • Participants' perceived quality of life
  • Length of hospital stay
  • Number of primary care contacts
  • Adverse effects of nutritional supplementation
  • Level of care and support required
  • Number of hospital and care home admissions, re-admissions
  • Nutritional status
  • Percentage change in dietary intake
  • Compliance with intervention
  • Economic outcomes.

Independent Variables

  • Interventions were aimed at improving the intake of protein and energy using only the normal oral route
  • Supplements in the form of commercial sip feeds, milk-based supplements and fortified normal food sources.
Description of Actual Data Sample:

Initial N: 49 trials 

Attrition (final N): 49 trials representing 4,790 participants, 62% female

Age: Mean age varied from 65 years to 88 years; weighted mean age was 77 years

Ethnicity: Not reported

Location: Europe, United States, Canada, Australia and Hong Kong.


Summary of Results:

Other Findings

Most included trials had poor study quality.

Interventions used in the trials aimed to provide between 175 additional kcal per day and up to a maximum of 1,000 additional kcal per day. Additional protein was between 10g and 36g per day.

Minimum time period of the intervention was 10 days and the maximum was 18 months. 

The pooled weighted mean difference for percentage weight change showed a benefit of supplementation of 2.3% (95% confidence interval, 1.9 to 2.7) from 34 trials.

There was a reduced mortality in the supplemented compared with control groups (relative risk=0.74; 95% confidence interval, 0.59 to 0.92) from 32 trials.

The risk of complications from 14 trials showed no significant difference (relative risk=0.95; 95% confidence interval, 0.81 to 1.11).

Few trials were able to suggest any functional benefit from supplementation.

The pooled weighted mean difference for length of stay from 10 trials also showed no statistically significant effect (WMD -1.98 days, 95% confidence interval, -5.20 to 1.24). 

Author Conclusion:

Supplementation produces a small but consistent weight gain in older people. There may also be a beneficial effect on mortality. However, there was no evidence of improvement in clinical outcome, functional benefit or reduction in length of hospital stay with supplements. Additional data from large-scale, multi-center trials are still required.

Funding Source:
Reviewer Comments:

Authors note the following limitations:

  • Quality rating of the included trials as reported was poor
  • Analysis of outcomes on an intention-to-treat basis was deficient and this represents a source of bias
  • Reporting of numbers of participants who were allocated and assessed was inadequate
  • Reasons for losses to follow-up were often not reported.
Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes