- Click here for explanation of classification scheme.

To assess time expended by Registered Dietitians to conduct clinical and research activities during the MDRD Study.

Participants in the MDRD Study were divided into 2 groups based on the baseline GFR:

• Study A included those with moderate renal insufficiency: GFR: 25 – 55 mL/min/1.73m²
• Study B included those with advanced renal insufficiency: GFR: 13 – 24 mL/min/1.73m²

Because the time-log form was developed and implemented during the initial recruitment of participants, some early participant visits were not assessed. 

Recruitment:  The MDRD Study was conducted at 15 clinical centers throughout the continental USA.  A total of 840 men and women with chronic renal disease were included in the MDRD Study (details published elsewhere), and time-logs were used from 830 of the total 840 participants for this analysis.  

Design:  The MDRD Study was designed as a 2 x 2 factorial in order to evaluate effects of 3 dietary protein levels and 2 blood pressure levels.

Protein intake

1. usual: 1.30 g/kg per day
2. low: 0.58 g/kg per day
3. very low: 0.28 g/kg per day plus keto-amino acid supplement (also 0.28 g/kg per day)

 Blood pressure levels

1. usual: 107 mm Hg mean arterial pressure
2. low: 92 mm Hg mean arterial pressure

Subjects in Study A were randomly assigned to either usual or low dietary protein and usual or low blood pressure goals.  Subjects in Study B were randomly assigned to either low or very low dietary protein and usual or low blood pressure goals.

The time-log form was developed in order to document the time required by the RD in various activities related to effectively achieve the MDRD Study's nutritional objectives.  The nutrition intervention was consistent for all participants and emphasized long term adherence.  Protein intake was of primary focus.  Counseling for weight loss, sodium restriction and fat modification were also included when indicated.

• The first 4 months of follow up were the most intensive and included instruction in self-monitoring, goal setting, problem solving, food purchasing and eating out.
• Months 5-24 focused on strengthening knowledge and skills, providing feedback and modeling desired behaviors.
• Emphasis after month 24 included support activities to maintain motivation, promote self-efficacy, prevent relapse and sustain adherence.  Time-log data was collected through the 36 month visit.

Blinding used:  none reported 

Intervention:  A time-log form was developed, pilot tested and refined during the initial year of recruitment of patients into the MDRD Study.  This time-log form was then completed monthly by the RD for each participant being followed in the MDRD Study with data collected and evaluated in the following categories: 

• The clinical practice variable included time spent on preparation/follow-up, counseling, charting, telephone calls and patient conferences.
• The research variable included time spent on food record documentation, anthropometry and other activities specific to the research protocol.

Statistical Analysis:   Descriptive statistics were used to summarize time spent on dietitian activities and total time reported.  One-way ANOVA or two sample t tests were used to compare differences in time by diet group, age, gender, race, education and renal diagnosis.  Because preliminary analyses indicated no significant differences in dietitian time spent for participants in the low protein diet group of Study A compared with Study B, analyses reported in this study reflect combined data of the (A and B) low protein diet groups.  All statistics were calculated using SPSS-X, release 4.0, 1994.  

Timing of Measurements:  monthly

Dependent Variables: 

• Time (minutes) spent by the RD in patient counseling, assessed by time per follow-up visit and assessed by time per diet group (ie, usual, low or very low protein intake), measured using the pilot tested time-log form.

• Dietitian activities were assessed using the following categories:

  • Preparation/follow-up time
  • Counseling
  • Charting
  • Telephone calls
  • Patient conferences
  • Food record documentation
  • Anthropometry
  • Other

Independent Variables: 

1. Levels of protein intake:

• usual: 1.30 g/kg per day
• low: 0.58 g/kg per day
• very low: 0.28 g/kg per day plus keto-amino acid supplement (also 0.28 g/kg per day)

2.  Blood pressure

Control Variables: 

• Age
• Gender
• Race
• Marital status
• Education
• Renal diagnosis

Initial N:  The MDRD Study included 840 men and women with chronic renal disease.  Data from time-log forms completed at least once for 830 of the 840 participants were used for this analysis.  Over the 36 months of follow-up, data were included from 19,494 time-logs.

Attrition (Final N):  NA

Age:  18 to 70 years of age 

Ethnicity:  reported elsewhere

Other Relevant Demographics:  gender, race and marital status reported elsewhere, education level included (< 12 years, 12 years, or > 12 years).

Anthropometrics:  reported elsewhere

Location:  continental USA

Time requirements: 

Time by diet group:  Significantly more RD time was required for subjects consuming very low protein diets than for those consuming usual or low protein diets.

Dietary protein intake (estimated from 24 hour UUN excretion) was compared at baseline and follow-up across study groups.  Those in the usual protein diet group increased their protein intake by about 8%.  Those in the low protein group decreased their intake to about 75% of baseline, and those in the very low protein group decreased to around 50% of their baseline intake (statistical analyses not provided). 

Time by sociodemographics and renal diagnosis:  Age, gender, race, marital status, and renal diagnosis did not influence time requirements.  There was a significant inverse association between education level of the subjects and the RD time for counseling in follow-up periods 5-12 months (p<0.05) and 13-24 months (p<0.01). 

Mean time in minutes (+SD) for dietitian activities 

Months

1-4

Months

5-12

Months

13-24

Months

25-36

Usual protein group (n=255)

Low protein group (n=347)

Very low protein group (n=104)

Usual protein group (n=286)

Low protein group (n=406)

Very low protein group (n=121)

Usual protein group (n=274)

Low protein group (n=386)

Very low protein group (n=108)

Usual protein group (n=167)

Low protein group (n=228)

Very low protein group (n=66)

Counseling

59+25

68+29

74+31**

45+16

51+19

56+19*

38+14

41+16

47+18**

34+14

36+15

41+16

Mean total time

171+68

186+69

204+73**

131+40

146+47

157+56*

120+37

128+43

138+44**

112+39

118+41

118+41

 *p<0.05; **p<0.01 (results from one-way ANOVA)

The first 4 mos of follow-up were the most labor intensive.  Average total time was 183+70 minutes per visit during the first 4 mos and 116+41 minutes per visit during the 3rd year.  Most of the decline was in counseling time, while time for research remained fairly constant at about 30-35 minutes per visit. 

Professional time required to implement effective medical nutrition therapy is a key factor related to cost-effectiveness and cost-benefit analysis.

Time requirements declined over the 3 year period, especially in preparation/follow-up and counseling activities.  Sustained support from the RD helped prevent relapse and improved the participants' application of skills over time.

Greater time requirements were necessary when working with participants who had completed fewer years of education.

The time-log data from this study provide important information for administrators, nutrition professionals, and scientists involved in the treatment and investigation of diet and renal issues. The data have direct application in planning research studies with similar subjects and when determining staffing patterns for nutrition programs aimed at the management of renal disease. This study demonstrates the extensive skills necessary to effectively deliver renal nutrition programs.

Government:

NIDDK, Health Care Financing Administration

Validation studies for the time-log developed were not conducted, however, several versions of the form were pilot-tested prior to initiation of data collection after the first year of recruitment into the MDRD Study.  Dietitians were trained in research procedures and aware of accurate and complete data collection.

Adherence to dietary protein was estimated using 24 hour UUN excretion data (mean + SD per group).  Using this method, adherence to protein goals was slightly below target for the usual group and somewhat above target for the low and very low groups, although long term adherence to the diet protocol was an emphasis of the Nutrition Intervention Program, through which the data for this time analysis were collected.