EAL

CKD: Dietary Fat Requirements (2010)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the incidence of and the etiologic variables for post-transplant hypercholesterolemia renal allograft recipients and the effectiveness of dietary intervention alone or in combination with gemfibrozil.

Inclusion Criteria:

Post-transplanted patients with a functioning renal graft for a minimum of three months
Total cholesterol higher or equal to 240mg per dL on two separates determinations while on maintenance immunosuppression
Recipients: 138, cadaver kidney; 30, kidney-pancreas; 32, living-related kidney recipients.

Exclusion Criteria:

Not mentioned.

Description of Study Protocol:

Recruitment

Patients were recruited from a post-transplant unit center between January 1, 1988 and June 30,1992.

Design

Nonrandomized clinical trial. Post-transplant patients with hypercholesterolemia who had functioning renal grafts for at least three months of post-transplant were evaluated. They were compared with a post-transplant patients without hyperlipidemia. All patients with a cholesterol of 240mg per dL on maintenance immunosuppression had undergone dietary counseling. After an initial assessment of their dietary intake, the patients followed a low fat (25% to 30% ), low cholesterol (less than 300mg per day) diet for six months. Those who were more than 20% of their ideal body weight followed a hypocaloric weight reduction protocol. The level of dietary compliance was evaluated by 72-hour food intake record or 24-hour dietary recall.

The patients' compliance was graded according to the cholesterol intake: Grade 1, less than 300mg; Grade 2, between 300mg to 500mg and Grade 3, more than 500mg cholesterol consumption per day. After six months of dietary intervention, gemfibrozil was initiated when the serum cholesterol was greater than 240mg per dL. These group of patients were analyzed at the start of drug intervention and at three-month intervals during 12 months of therapy. Dietary compliance was reinforced at each office visit.

Blinding Used

Not used. Lab tests.

Intervention

Low-fat cholesterol diet (30%) and low cholesterol diet (less than 300mg per dL).

Statistical Analysis

Standard paired or unpaired Student T-test or analysis of variance were used for comparison between groups.

Data Collection Summary:

Timing of Measurements

Age, race, gender, incidence of diabetes, body weight transplantation and weight gain were taken during the first six months following transplantation. Biochemistry measurements were taken baseline, after six and twelve months during the first post-transplant year. However, the measurements for patients with dietary intervention were taken in the first six months.

Dependent Variables

Serum total cholesterol
Serum albumin
Body weight
Serum creatinine.

Independent Variables

Low fat (25% to 30%) and low cholesterol (less than 300mg per day) diet.

Control Variables

Cyclosporine level
Prednisone
Diabetes.

Description of Actual Data Sample:

Initial N: 200; hypercholesterolemia, 138 (62% male, 38% female); without hypercholesterolemia, 62 (77% male, 23% female)
Attrition (final N): 200; hypercholesterolemia,138 (62% male, 38% female); without hypercholesterolemia, 62 (77% male, 23% female)
Mean Age: 42 years
Other relevant demographics: Age, race and incidence of overt diabetes were not different between groups at baseline. However, post-transplant hypercholesterolemia was significantly more prevalent in females and in recipients with higher cholesterol levels at the time of transplantation.
Anthropometrics: Body weight was not different between groups
Location: St Louis, Missouri.

Summary of Results:

Clinical and Laboratory Variables in Recipients with (Group A) and Without (Group B) Hypercholesterolemia

Variables	Group A			Group B
Variables	Baseline	Six Months	12 Months	Baseline	Six Months	12 Months
Fasting blood glucose (mg per dL)	133.6±6.2	131.5±6.7	141.3±17.5*	141.3±17.5	111.5±9.5	105.2±10.7*
Serum Albumin (mg per /dL)	3.5±0.05	4.1±0.04	3.6±0.07	3.6±0.07	4.2±0.08	4.2±0.09
Serum creatinine (mg per dL)	2.1±0.15	1.7±0.06	2.0±0.23	2.0±0.23	1.7±0.08	2.0±0.19

*P=0.003 for Group A vs. Group B

The Effect of Dietary Modification and Patient Compliance with Diet on Post-transplant Body Weight and Serum Cholesterol in Patients with Hypercholesterolemia

Variables	Grade 1 (N=36) (Less than 300mg Cholesterol)		Grade 2 (N=51) (300mg to 500mg Cholesterol)		Grade 3 (N=36) (More Than 500mg Cholesterol)
Variables	Baseline	Six Months	Baseline	Six Months	Baseline	Six Months
Body weight (kg)	75.1±2.1	75.3±2.1	74.3±2.4	77.0±2.3^a	87.7±3.4^b	90.6±3.6^c
Serum total cholesterol (mg per dL)	244.1±6.7	252.7±8.4	266.9±6.2	272.3±6.4	283.8±8.5^d	309.3±11.7^c

^a P<0.02, six months vs. baseline; ^bP=0.0003, baseline Grade 3 vs. baseline Grades 1 and 2; ^cP<0.001, six months Grade 3 vs. six months Grades 1 and 2; ^dP=0.001, baseline Grade 3 vs. baseline Grade 1.

Other Findings

Patients without hypercholesterolemia who did not receive the dietary intervention showed a significant increase in the body weight during six months (P<0.05)
The level of dietary compliance was Grade 1 in 36 patients, Grade 2 in 51 patients and Grade 3 in 36 patients.

Author Conclusion:

A dietary modification using hypocaloric, low-fat, low-cholesterol diet alone did not reduce serum total cholesterol levels, even in seemingly compliant patients.

Funding Source:

Other:

no data

Reviewer Comments:

Some patients had two organs transplanted at the same time (kidney plus pancreas).

Recipients with diabetes or those who developed diabetes after the transplant were included in the same analysis with non-diabetic recipients. It Increases the bias of the results.

Anthropometric measurement was based only on body weight.

Poor compliance to the diet was noted.

Only 138 patients with hypercholesterolemia received dietary intervention (low fat and cholesterol diet) and they were compared to 62 patients without hypercholesterolemia. Not sure what diet the 62 controlled patients received.

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?		No
	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?	No
	2.2.	Were criteria applied equally to all study groups?	No
	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?	No
3.	Were study groups comparable?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	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.)	No
	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?	N/A
	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?		No
	4.1.	Were follow-up methods described and the same for all groups?	No
	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%.)	No
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	???
	4.4.	Were reasons for withdrawals similar across groups?	???
	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?		No
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	No
	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?	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?		No
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	No
	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?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	No
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	No
	6.6.	Were extra or unplanned treatments described?	No
	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?		No
	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?	No
	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?	No
	7.7.	Were the measurements conducted consistently across groups?	No
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		No
	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?	No
	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)?	No
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	No
	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?		No
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	No
10.	Is bias due to study's funding or sponsorship unlikely?		???
	10.1.	Were sources of funding and investigators' affiliations described?	No
	10.2.	Was the study free from apparent conflict of interest?	???