CKD: Physical Activity (2008)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To evaluate whether rehabilitation services, including regular exercise, during the first six months, with a follow-up of one year, prevent or reverse physical deconditioning and disruption of vocational activity more effectively in pre-dialysis patients, than stable dialysis patients.
Inclusion Criteria:
- Pre-dialysis patients (P), expected to require dialysis within six to 12 months (mean, 12.1±0.32 months)
- Dialysis patients (D) on hemodyalisis for one to five years
- Patients with current or recent employment (within the preceding year) and no serious coexisting disease, such as diabetes.
Exclusion Criteria:
- Pre-dialysis and hemodialysis patients who did not fit the inclusion criteria.
- Patients dropped out from the study due to: Kidney transplant (four); other medical reasons (five); declined to finish the study (five).
Description of Study Protocol:
Recruitment
Urban dialysis center for pre-dialysis patients.
Design
- Non-randomized clinical trial for one year; pre-dialysis and hemodialysis patients enrolled were distributed to the exercise coaching and rehabilitation counseling (R) or the control (C) group
- Rehabilitation and coaching exercise were provided in the first six months and in the last six months, patients were followed-up without any treatment
- Patients could choose to exercise at home, in a physicial therapy gym with the coach or join the community activities
- All quality of life parameters and exercise testing were assessed at baseline, six months and 12 months
- All patients at the rehabilitation-exercise group discussed the diary weekly, with the exercise coaching during the first three months and monthly during Months Four to Six.
Blinding Used
Not used; physicians.
Intervention
- Rehabilitation and exercise coaching (individualized prescription): Low-intensity strengthening and stretching plus aerobic exercises for up to one hour per week for the first three months and one hour per month for Months Four to Six, totalling 16 hours with supervision. The goal was to exercise for 30 minutes five days per week during the 26-week program.
- Control exercise: No training.
Statistical Analysis
- 2x2x4 factorial design with two between-group variables (pre-dialysis vs. dialysis and rehabilitation vs. control) and one within-subject variable (repeated-measures initially and after three, six and 12 months)
- Statistical significance was considered when P<0.05 and near-significant difference when P<0.10.
Data Collection Summary:
Timing of Measurements
Disease, disability, exercise and quality of life were measured at baseline, six months and 12 months.
Dependent Variables
- Disability: Karnofsky Index of Disability (KID) by patients and physicians
- Disease: Coexisting Disease Index (CDI), 0=absent; 1=mild or moderate; 2=severe
- Quality life: Sickness Impact Profile (SIP)
- Physical functional status: Self-paced six minutes of walking, including resting heart rate and perceived exertion.
Independent Variables
Rehabilitation and coaching exercise vs. control non-exercise.
Control Variables
Recombinant human erythropoietin.
Description of Actual Data Sample:
- Initial N: 26 Pre-dialysis; 24 dialysis
- Attrition (final N): 18 pre-dialysis (nine males, nine females); 18 dialysis (11 males, seven females)
- Attrition: Ranged from 185 to 17% for pre-dialysis and 18% to 16% for dialysis
- Mean age: 47.0
- Ethnicity: Not mentioned.
Other Relevant Demographics
- 60% of pre-dialysis patients started dialysis during the study and only 39% of pre-dialysis patients did not begin dialysis at study completion
- All dialysis patients were treated by hemodialysis, except for one patient, who changed to peritoneal dialysis three months into the study.
Anthropometrics
Matched at the baseline for age, gender and time on dialysis
Location
Northwest Kidney Centers and University of Washington, Seattle.
Summary of Results:
Nine pre-dialysis (six men and three women) and nine dialysis patients (six men and three women) were in the rehabilitation group. Nine pre-dialysis (three men and six women) and nine dialysis patients (five men and four women) were in the control group.
Disease and Disability
- When the score for disease (CDI) was measured, in both control groups, predialysis (PC) and dialysis (DC), general health ratings became slightly worse during the year from 2.4 to 2.7 and from 2.6 to 2.8, respectively
- Although the rehabilitation (R) groups, PR and DR, improved health ratings from 2.7 to 2.6 and from 2.3 to 2.0, respectively, it was not statistically significant
- The symptom checklist score from zero to 40 showed that PR, when compared to PC, was the only group in which the symptoms decreased significantly after six months and 12 months; P<0.001 and P<0.05, respectively
- There was a tendency for the P groups to have fewer symptoms than the D groups over time
- When KID, the disability index, was measured, there was no change over time for either self-rated or physician-rated KID
- DR patients reported more disability than the other three groups and physicians initially rated D patients as slightly more disabled than P patients.
Exercise Testing
- P patients walked farther in six minutes than D patients, initially and at follow-up; P<0.05
- Overall, both distance walked and perceived exertion (PE) increased on successive tests; P<0.001
- DR increased the distance (performance) proportionally more than PE (effort), while DC increased PE more than distance from initially to six months. Nevetherless, PR increased both distance and effort at six- and 12-month tests (P<0.01), but not PC
- The ratio of distance (m) walked in six minutes, to resting heart rate change, from pre- to post-walk, increased over successive tests for R goups more than for C groups; P<0.05
- The resting heart rate change was greastest in PR and similar in the other three groups, but not statistically different.
Quality of Life
There was a tendency in the R groups to improve the quality of life in contrast to the C groups, which showed worsened scores of quality of life without statistical significance. However, the PR group improved significantly the quality of life score, while PC group worsened after treatment; P<0.05. This tendency was mantained by the end of the study, but it was not statistically significant.
Other Findings
- The CDI correlated with self-rated effect (R=-0.35; P=0.04), self-rated KID (R=-0.37; P=0.03), D symptoms (R=+0.34; P=0.04) and physical SIP (R=+0.40; P=0.02), but not with physician-rated affect or physician-rated KID
- Hematocrit increased from baseline to follow-up in both R groups: PR from 32.0 to 36.7 (P<0.05) and DR from 30.4 to 34.4 (NS).
Author Conclusion:
- Rehabilitation and exercise program improved or stabilized the quality of life in pre-dialysis patients, but declined in this same population without exercise
- Overall exercise and rehabilitation benefited more the pre-dialysis than dialysis patients
- Rehabilitation services are more beneficial before than after patients stabilize on dialysis and quality of life monitoring should continue indefinitely
- The authors suggested that their results are consistent in the predicted direction, if not always statistically significant with the small number of patients
- Larger longitudinal studies are needed.
Funding Source:
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Reviewer Comments:
- Small sample size, increasing the possibility of a Type Two error
- Population chosen was "healthier" than the general pre-dialysis and dialysis population, which can bring bias to the effectiveness of the intervention
- Patients in the control group did not have a sham training exercise and follow-up
- Only about 39% of the pre-dialysis patients finished the study without needing to begin dialysis
- The time in dialysis has a huge variation from one to five years, making it difficult to interpret the findings
- Overall, the study had many flaws from the design, execution and presentation of the data, making it difficult to interpret the results.
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Quality Criteria Checklist: Primary Research
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| 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? | Yes | |
| 2.3. | Were health, demographics, and other characteristics of subjects described? | No | |
| 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? | No | |
| 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? | 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? | No | |
| 4.4. | Were reasons for withdrawals similar across groups? | No | |
| 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.) | No | |
| 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? | Yes | |
| 6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | Yes | |
| 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? | 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 | |
| 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? | N/A | |
| 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? | No | |
| 7.6. | Were other factors accounted for (measured) that could affect outcomes? | ??? | |
| 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? | No | |
| 8.1. | Were statistical analyses adequately described and the results reported appropriately? | No | |
| 8.2. | Were correct statistical tests used and assumptions of test not violated? | ??? | |
| 8.3. | Were statistics reported with levels of significance and/or confidence intervals? | No | |
| 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)? | ??? | |
| 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? | No | |
| 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? | Yes | |
| 10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
| 10.2. | Was the study free from apparent conflict of interest? | Yes | |