EAL

ONC: Nutrition Status and Outcomes in Adult Oncology Patients (2013)

Citation:

Martin L, Watanabe S, Fainsinger R, Lau F, Ghosh S, Quan H, Atkins M, Fassbender K, Downing GM, Baracos V. Prognostic factors in patients with advanced cancer: Use of the patient-generated subjective global assessment in survival prediction. J Clin Oncol. 2010 Oct 1; 28(28): 4,376-4,383.

PubMed ID: 20805456

Study Design:

Prospective Cohort Study

Class:

B - Click here for explanation of classification scheme.

Quality Rating:

NEUTRAL: See Quality Criteria Checklist below.

Research Purpose:

To define elements of the patient-generated Subjective Global Assessment (PG-SGA) independently prognostic of survival in patients with advanced cancer and to determine their prognostic accuracy
To compare the predictive accuracy of patient- and physician- reported performance status (PS).

Inclusion Criteria:

Metastatic cancer
Older than 18 years
Referred to the Regional Palliative Care Program.

Exclusion Criteria:

None stated.

Description of Study Protocol:

Recruitment

Patients in the Regional Palliative Care Program (RPCP) were accrued from palliative home care, an inpatient tertiary palliative care unit (TPCU), and an outpatient pain and symptom control consult service (PSCS) located in the regional cancer treatment center.

Design

Prospective nested cohort. After accrual of patients, the cohort was divided into two groups for analysis. In the training set, data from the palliative home care was used to determine elements of the PG-PGA prognostic of overall survival, build a predictive model including these features and assess the predictive accuracy of the model. In the validation set, data from the PSCS and TPCU tested the predictive accuracy of the survival model. In the comparison of patient- and physician-reported PS, subsets from both groups were combined.

Statistical Analysis

Differences between groups were evaluated with independent T-tests for continuous variables and χ² tests for categorical variables. The primary outcome was overall survival. The Kaplan-Meier method established the effect of each variable on survival; log-rank tests were used to compare survival curves within each variable. The Cox proportional hazard model was used to obtain hazard ratios and their corresponding 95% CI.

Data Collection Summary:

Timing of Measurements

First referral (home care, PSCS) or admission (inpatient TPCU).

Dependent Variables

Height, weight, weight change: Recorded one and six months before referral or admission with the one-month change being used when possible or imputed from the six-month weight change (5% of patients)
Dietary intake, 13 nutrition impact symptoms, performance status (PS) on the PG-SGA were completed by the patients
Palliative Performance Scale (PPS) was completed by the physician. The PPS contains five domains:
- Ambulation
- Activity level and evidence of disease
- Self-care
- Oral intake
- Level of consciousness.
PPS has 11 categories (0%-100%) and is scored in 10% increments; a lower score indicates worse function.

Independent Variables

Overall survival as predicted by PG-SGA, PS and PPS.

Description of Actual Data Sample:

Initial N

Training set: 1,164 (566 males, 598 females)
Validation set: 603 (288 males, 315 females).

Age

Training set: 66.8 years
Validation set: 60.6 years.

Anthropometrics

Height, weight and weight change were similar between the two groups.

Location

Edmonton, Canada.

Summary of Results:

Findings

The relationship of percent weight change to overall survival, by deciles, was U-shaped; shortened survival was associated with increasing weight loss and weight gain compared with stable weight. Survival was shorter for all BMI less than 30.0kg/m².
Shortened survival was associated with the three low food intake categories ("little solid food,' "only liquids/nutritional supplements" and "very little of anything") that were subsequently categorized as abnormal food intake. Median survival fitness for patients with normal intake (5.0 months; 95% CI: 3.7 to 6.2 months), normal food at reduced amounts (3.4 months; 95% CI: 3.0 to 3.8 months) and abnormal intake (2.1 months; 95% CI: 1.7 to 2.4 months) were different (P=0.001).
Nutrition impact symptoms associated with shorter survival were no appetite, feel full quickly, altered taste, dry mouth and dysphagia
Women had longer median survival compared with men [3.6 months (95% CI: 3.1 to 4.1 months) vs. 2.8 months (95% CI, 2.4 to 3.1 months); P=0.001]
Patients with lung and GI cancers had the shortest survival compared with other cancers
Age was not related to survival
Patient-reported PG-SGA PS scores of zero to two had longer median survival [4.3 months (95% CI: 3.8 to 4.8 months)] than patients with PS 3 [2.5 months (95% CI: 2.2 to 2.8 months)] or patients with PS 4 [1.3 months (95% CI: 0.05 to 2.0 months) P<0.001]
Discrimination (C-statistic) was assessed in a base model containing two variables: cancer diagnosis and PG-SGA PS, which demonstrated excellent predictive discrimination. The addition of percent weight change, food intake and dysphagia did not improve predictive accuracy above that of the base model.
The validation set had a different median survival [PSCS: 3.8 month (95% CI: 3.4 months to 4.2 months) vs. TPCU: 1.1 month (95% CI: 0.9 to 1.2 months); P<0.001]. However, accuracy (C-statistic) of survival prediction was similar for these patients and data were pooled.
Patients in the validation set were younger and had different distributions of PS and dietary intake with a higher overall symptom burden compared with patients in the training set. Neither median survival nor follow-up differed from the training set. Discrimination of the base and full models of survival prediction was similar to that of the training set.
The subset of 1,283 patients who had a PPS on the same date as the PG-SGA had an indistinguishable overall survival predicted by the patient- and physician-reports PS.

Author Conclusion:

There is a high probability of concordance between predicted and observed survival for patients in distinct palliative care settings based on patient-reported information.

Funding Source:

Government:	Canadian Institutes of Health Research
University/Hospital:	University of Alberta, Cancer Care, Regional Palliative Care Program, Education Resources, Alberta Health Services, Edmonton, Alberta, School of Health Information Science, University of Victoria, and Palliative Medicine, Research and Development, Victoria Hospice, Victoria, British Columbia, Canada

Reviewer Comments:

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)	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.)	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.)	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?		N/A
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	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%.)	N/A
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	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
5.	Was blinding used to prevent introduction of bias?		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.)	N/A
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	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
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?	N/A
	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?	N/A
	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)?	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
9.	Are conclusions supported by results with biases and limitations taken into consideration?		N/A
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	N/A
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