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Study Description
The relationship between elevated phosphorus levels and morbidity and mortality in patients
with chronic kidney disease (CKD) is well recognized, and dietary phosphorus restriction is
a mainstay of phosphate management. Despite this, appropriate control of phosphate intake
remains sub-par, due in part to the difficulties that patients have understanding phosphate
content in foods. Randomized trials have shown that intensive, individualized dietary
counseling can improve patient knowledge about phosphorus and help control
hyperphosphatemia; however, maintaining this level of counseling is time-consuming, costly,
and impractical. Given the recognized nephrology workforce shortage, there is a crucial need
for systems to fill this gap with novel technologies to educate patients, and it is vital
that a better understanding of the effects of novel nutritional intervention counseling
methods on patient knowledge, nutritional intake and nutritional status be evaluated in CKD
patients.
Furthermore, to effectively engage in the patient side of the education process, those who
receive it, the patients, must be able to comprehend information and draw on it for
decision-making. Novel educational interventions may be better suited than traditional
methods to circumvent literacy limitations. Therefore, it is vital to assess the relation of
functional health literacy of this population in both traditional and emerging educational
venues.
Finally, the importance of phosphorus control for patients with CKD has traditionally been
to prevent bone disease. More recently it is recognized that poor phosphorus control
correlates with cardiovascular disease, of which patients with CKD carry an enormous burden.
Similarly, there has recently been much attention to circulating endothelial cells (CECs)
as a novel marker for cardiovascular risk in this population. While the ultimate test would
be to determine if controlling phosphorus impacts on cardiovascular events, that is beyond
the scope of this project. Therefore, we propose to measure levels of CECs as an
intermediary step toward cardiovascular events, in correlation to phosphorus intake.
Hypothesis 1: Novel nutritional educational interventions of dietary phosphorus can be
useful for providing improvements on phosphorus knowledge and control of intake.
Significance: Such methods can be self-sustaining, and therefore a practical solution to
the problem of providing continuous and repeated educational interventions given limited
provider time and resources.
Hypothesis 2: A higher level of health literacy in individuals with CKD is associated with
greater knowledge of and compliance with recommended dietary phosphorus intake.
Significance: A better understanding of obstacles to optimal nutritional intake will lead to
improved methods for nutrition intervention counseling. Alternative measures to educate
those with lower health literacy may require a shifting of resources for this subgroup of
individuals.
Hypothesis 3: Higher dietary phosphorus intake in individuals with CKD correlates with
higher levels of CECs.
Study Design
Specific Aim 1: To examine the effect of a novel, web-based method of educating CKD
patients on patient knowledge and dietary intake of phosphorus. We will compare 2 methods
for educating CKD patients about dietary phosphorus intake:
1. Usual care, consisting of individualized care/counseling by a nephrologist.
2. Usual care, plus review of the Kidney School (KS) Nutrition Module (see below). To
compare gains in phosphorus knowledge after 1 month. To compare compliance with dietary
phosphorus intake, as measured by mineral metabolism laboratory values (serum
phosphorus, calcium, PTH, calcium-phosphorus product) and 3-day dietary diaries.
Specific Aim 2: To determine if the S-TOFHLA predicts CKD patients' knowledge and
compliance with recommended dietary phosphorus intake:
1. To measure health literacy in patients undergoing maintenance hemodialysis, using the
S-TOFHLA.
2. To assess correlations between health literacy and knowledge of phosphorus.
3. To assess correlations between health literacy and compliance with CKD dietary
phosphorus guidelines, as measured by mineral metabolism laboratory values (serum
phosphorus, calcium, PTH, calcium-phosphorus product), and dietary phosphate intake, as
measured by 3-day dietary diaries.
4. To assess correlations between health literacy and compliance with CKD dietary
phosphorus guidelines, following usual care versus an eHealth nutrition intervention.
Specific Aim 3: To determine if higher dietary phosphorus intake correlates with higher
levels of CECs.
1. To measure CEC levels in patients with CKD.
2. To assess correlations between dietary phosphorus intake, serum phosphorus levels, and
CECs in patients with CKD.
Following enrollment and informed consent, subjects will be randomized to one of two arms
(group1: usual care; group 2: usual care plus KS module). All subjects will undergo baseline
data collection, as shown in table 1. KS and Survey information is as follows:
Kidney School (KS). KS (http://www.kidneyschool.org) is an online, personalized, interactive
self-management learning center created by the Madison, WI based Medical Education Institute
(MEI) and organized into fifteen 20-30 minute modules, each focused on a different topic
related to kidney disease and its treatment, including nutrition. Content is based on 10
years of research conducted by the Life Options Rehabilitation Program, with internal and
external expert review. The nutrition module is tailored for patients with or without
diabetes.
KS modules contain a pre/post-test, instructional content, patient quotes,
graphics/animations, photos, pop-ups, a resource list containing books and relevant website
links, and a certificate of completion. The content branches to provide tailored information
to each user according to user responses. These responses also create a Personal Action Plan
in each module that can be printed and used for content review and setting goals. A custom
graphic interface with navigation buttons was designed for KS, and each module has
customized Javascript programming, as the content branching patterns are unique.
Proprietary Information. The mission of the non-profit MEI is to help people with chronic
diseases learn to manage and improve their health, through research and education. The MEI
believes charging a fee for educational materials can be a barrier between patients and the
information they need to live successfully with a chronic disease. All MEI-developed patient
education materials are therefore free. KS is entirely proprietary to the MEI, but will
continue to be available free of charge via the Internet.
HIPAA. KS is fully compliant with HIPAA standards. S-TOFHLA. An abbreviated version of the
test of functional health literacy in adults, the S-TOFHLA is widely used by health care
providers to determine the adequacy of their patients' understanding of health care
materials needed for their health care or education, as well as by researchers to assess
health literacy as a variable in research. It categorizes individuals as having adequate,
marginal or inadequate health literacy, can be administered in 12 minutes, and has been used
in patients with a variety of chronic diseases.
CKD Knowledge Assessment Tool (CKDKAT) of Nutrition. The CKDKAT of nutrition is a revised
version of our original CKDKAT, which addresses only nutritional knowledge specific to CKD.
Fifteen of 25 questions are phosphorus-specific, with the remaining 10 concerning sodium,
potassium and protein intake.
SF-12v2. The SF-12 Health Survey version 2 is a 12-item measure of health related quality of
life. Widely used in research in a variety of disease states, including CKD, it provides
physical and mental component summary scores with a strong concordance with the lengthier
SF-36. Given that we will be administering multiple cognitive and behavioral surveys to
subjects, the shorter version will be used.
Kidney Disease Self-Management Survey (KDSMS). Developed by MEI, the KDSMS is a 58-item
Likert scale with 6 subscales, based on theories deemed important for self-management
education in other chronic diseases, including the health belief model, self-efficacy,
behavioral intent, and the transtheoretical model. These theories converge into a
self-management education schema that emphasizes the importance of information, support,
modeling, planning, practice and monitoring, and reflection in patient self-management
education. The 6 subscales are: 1) Self-monitoring, 2) Adjusting to symptoms, 3) Lifestyle
behaviors, 4) Medication-taking, 5) Information seeking, 6) Doctor/patient communication.
24 hour recall diaries. After collecting the information from subjects, nutrient analysis
will be performed using The Food Processor SQL Nutrition Software (ESHA Research, Salem,
Oregon).
The study instruments will all performed for research purposes. While some of them (the
S-TOFHLA, 3-Day Dietary Diaries) have been used as part of patient care, this is not
routine, and it is not done at our facilities.
Lab work collected will consist of serum phosphorus, calcium and intact-parathyroid hormone
levels. As these are routinely collected prior to or during a regular CKD clinic visit, the
study coordinator will check to see if this data is already available, and will not
duplicate this blood work if it is. In addition, all subjects will have blood drawn (30 ml)
for assessment of circulating endothelial cells (CECs), a novel marker for vascular damage.
Following baseline data collection, group 1 will continue with their scheduled clinic visit,
while group 2 will spend approximately 30 minutes completing the KS nutrition module at a
dedicated computer education station at the UW Kidney Clinic. The study coordinator will
bring up the KS nutrition module (tailored for diabetes as a co-morbidity if appropriate).
After completion of the KS nutrition module, patients will receive a personalize action
plan, and then proceed with their scheduled clinic visit.
All subjects will then be asked to return in 30-60 days to repeat some of the survey
information and blood work.
Subject Population
All subjects (N = 100) will be recruited from the UW Health Kidney Clinic. We will recruit
individuals in the later stages of kidney disease: Stages 3 and 4. Staging of CKD is
determined by estimating the glomerular filtration rate (e-GFR). The e-GFR is automatically
calculated with each outpatient serum creatinine ordered through the UW labs, and so this
information is readily available. Stage 3 is defined as GFR of 30-59 milliliters/minute (~ ½
to ¼ of normal kidney function), and Stage 4 is defined as a GFR of 15-29 milliliters/minute
(~ ¼ to ⅛ of normal kidney function). Stage 5 is kidney failure (GFR < 15
milliliters/minute).
All patients between the ages of 18 and 89 with CKD stage 3 or 4 who are seen in the UW
Health Kidney Clinic will be invited to participate in the study by a member of the study
personnel prior to beginning the class or while waiting for their clinic visit. Fliers
briefly describing the study with contact information for those interested will be available
at the receptionist area in the UW Kidney Clinic and in the computer-station education area.
Demographic information collected will include age, gender, race, length of time with known
CKD, education level, and home computer ownership.
Subjects will receive modest compensation for their time and effort ($10 after completion of
first set of data collection, $25 after completion of follow up data collection). No project
personnel will receive incentives for recruiting human subjects or for any other purpose
directly related to the study. The greater amount offered for the second visit is due to the
added inconvenience of returning for an additional visit.
Note, as prisoners are not seen in the UW Kidney Clinic, the study will not involve this
population.
Statistical Justification of Sample Size
We propose a sample size of 50 subjects for each of the cohorts. Pairwise comparisons of
mean knowledge scores of Cohort 2 with Cohort 1 (i.e., the original cohort taking the test
prior to any educational intervention) will be conducted using two-sided t-tests to detect a
p-value of < 0.05. Adjustments will be made for demographic factors known to be related to
chronic disease knowledge, including age, race, gender and education. The effective sample
size will provide 80% power to detect a difference in mean knowledge scores of 3 or more
questions.
Correlation between higher levels of functional health literacy and increased knowledge of
kidney disease will be determined using Spearman rank-order correlation.
Risks and Benefits to Participants
It is not anticipated that there are any significant or sustained risks to subjects of
participation in the study. There is the potential for some mild discomfort from the
necessary blood draws, which occur twice per subjects.
Personal benefits to subjects: Subjects randomized to the KS nutrition module may receive
benefit from the personalized action plan, and may gain knowledge of nutritional needs for
their chronic condition.
Scientific benefits from the study: A better understanding of obstacles to optimal
nutritional intake will lead to improved methods for nutrition intervention counseling.
Alternative measures to educate those with lower health literacy may require a shifting of
resources for this subgroup of individuals.
Consent Procedures
As the study requires the ability to fill out multiple surveys and use the Internet, only
individuals who can provide their own consent can participate. The consent process will be
conducted by either the Study Coordinator (Lynn Jacobson) or the PI (Jonathan Jaffery). Upon
agreeing to enroll in the study, the subject with a copy of the consent form (see attached).
The individual obtaining consent will remain available to answer any and all questions.
Changes to the protocol were submitted and approved:
The changes are being made because additional funding has been awarded to look further at
the same question in a slightly different patient population. The previously approved study
enrolls individuals with chronic kidney disease (CKD) stages 3 and 4 (moderate to severe
CKD). The proposed changes will include individuals with CKD 5 (end-stage kidney disease)
undergoing maintenance hemodialysis (MD). Given the major differences in how these groups
of patients receive care (clinic visits averaging every 3-6 months with occasional blood
work and primarily oral medications arranged per provider discretion for those with CKD 3
and 4, versus dialysis unit treatments of 3-4 hours/3 times weekly, with monthly blood work
and various oral and IV medications prescribed per protocols for those with CKD 5 on MD), it
is important to assess the proposed questions in both distinct groups.
1. Will enroll an additional 80 subjects, all with CKD 5, undergoing MD
2. Subjects will be randomized (1:1) to receive standard of care versus the intervention
with the tailored, web-based CKD nutrition module
3. Other interventions will be (for all 80 subjects) the same questionnaire instruments as
previously described
4. The timetable/duration of the study will be different for the MD group versus the CKD
3/4 group (see below)
5. No separate blood draws will be required of the MD group, as all the relevant lab tests
are measured as standard of care and recorded in the dialysis clinical database
Subjects with CKD 5 will have a decreased risk of adverse effects, due to the lack of any
need for blood draws. Additionally, the time spent performing study questionnaires or
engaging with the web-based module (via wireless-enabled laptop) will be during the 3-4 hour
dialysis treatment, and so will not prolong their visit length. Subjects with CKD 3 and 4
will not be affected by the changes.
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