EAL

CKD: Protein Restriction: Low Protein Diet (2018)

Author and Year:

Cianciaruso B et al 2008

PubMed ID:

17981885

Article Title:

Metabolic effects of two low protein diets in chronic kidney disease stage 4-5--a randomized controlled trial.

Authors:

Cianciaruso B, Pota A, Pisani A, Torraca S, Annecchini R, Lombardi P, Capuano A, Nazzaro P, Bellizzi V, Sabbatini M

Journal:

Nephrology, Dialysis, Transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association

Year of publication:

2008

Volume:

Issue:

Page numbers:

636-44

Study Design:

Randomized Controlled Trial

Risk of Bias Assessment Rating:

Positive

Inclusion Criteria:

753 consecutive patients with chronic kidney disease stages 2 - 5 were screened for eligibility between January 1999 - January 2003. 516 patients met the inclusion criteria of being at least 18 years old with chronic kidney disease stages 4 and 5 (estimated glomerular filtration rate of <30 ml/min/1.73m2 with <15% variation for 3 months). 423 patients were randomly assigned to one of two low protein diets and 392 patients completed the study for 6 - 18 months.

Exclusion Criteria:

Of 516 patients meeting inclusion criteria, 30 were excluded due to unstable renal function, 7 were excluded due to malignant disease, 7 were excluded due to treatment with immunosuppressant drugs, 31 were excluded for urinary protein excretion exceeding 5 g/24 hours, 3 were excluded due to pregnancy, and 15 refused to participate. Conditions requiring withdrawal from the present study included malnutrition, dialysis initiation, development of other serious medical conditions (myocardial infarction, acute myocardial ischaemia, presentation for congestive heart failure, stroke, successful resuscitation following cardiac arrest, coronary and peripheral revascularization procedures) and death.

Research Purpose:

The aim of this study was to compare the metabolic effects of two diets with different protein content (0.55 versus 0.80 g/kg/day) in patients with chronic kidney disease stages 4 and 5, based upon the monitoring of several markers of uraemic morbidity over 6 - 18 months.

Blinding efforts:

Randomization was completed by administrative staff personnel not involved in patient care.

Study Location:

Chronic Kidney Disease Clinic of the University Federico II of Naples, Italy

Source(s) of Funding:

Government, University/Hospital

Please specify names of funders:

Chronic Kidney Disease Clinic of the University Federico II of Naples, Italy. This study was partially funded in an unrestricted manner by PRIN-2001 (Grant 061427) of the Italian Ministry of University and Scientific Research.

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.)	Yes
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?	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?	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
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?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	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
	7.2.	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)?	Yes
	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?	Yes
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	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