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Self-reported Fatigue: Relationships with Physical Function and Oxygen Uptake in Leg Osteoarthritis and Type 2 Diabetes. Susan Murphy ScD, OTR 1,2,4 Neil Alexander MD 1,2,3,4. - PowerPoint PPT Presentation
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Self-reported Fatigue: Relationships with Physical Function and Oxygen Uptake in Leg Osteoarthritis and Type 2 Diabetes
Mobility Research Center (MRC)1; Department of Physical Medicine and Rehabilitation, University of Michigan2 ; Geriatrics Center and Division of Geriatric Medicine3 University of Michigan Hospitals;
VA Ann Arbor Health Care System Geriatric Research Education and Clinical Center (GRECC)4
Acknowledgments: National Institute on Aging; National Center for Medical Rehabilitation Research; American College of Rheumatology Research and Education
Foundation; VA Office of Research and Development (Rehab R&D and Medical Research Services)
Susan Murphy ScD, OTR1,2,4
Neil Alexander MD1,2,3,4
Presentation
Part I: Older women with leg osteoarthritisA. Daily pain and fatigue, in relation to
physical activityB. Behavioral intervention to reduce barriers
to PA and increase symptom controlPart II: Task-specific oxygen uptake and self-
reported fatigue in older adultsA. As predictors of mobility performanceB. In Type 2 diabetes mellitus
Symptoms and Physical Activity in Women with OA
• 60 women (40 with knee or hip OA, 20 controls)
• Mean age 64 + 8 years• 5 day home assessment
– Watch measured physical activity; recorded symptoms 6 times/day
– Pain/fatigue measured on scale of (0- none to 4-extremely severe)
– Fatigue defined as “tiredness or weariness”
Part I A: Clinical Research Questions
• How do pain and fatigue symptoms manifest in daily routines?
• How do pain and fatigue symptoms impact physical activity?
Pain in Women with OA and Controls (data depicted as means + SE)
0
0.5
1
1.5
2
2.5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
All Timepoints over 5 days
Pain
0-4
controlOA
Day 1 Day 2 Day 3 Day 4 Day 5
Fatigue in Women with OA and Controls (data depicted as means + SE)
0
0.5
1
1.5
2
2.5
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
All Timepoints over 5 days
Fatig
ue 0
-4
controlOA
Day 1 Day 2 Day 3 Day 4 Day 5
Momentary Within-Day Symptoms by WOMAC Physical Disability
0
0.5
1
1.5
2
2.5
Low WOMAC Physical Disability High WOMAC Physical Disability
Sym
ptom
Sev
erity
PainFatigue
Dependent Variable: Physical Activityβ
estimateStandard
Error P valueFatigue -30.08 6.21 <.0001
Pain -16.86 8.36 .04
Age -2.43 1.79 .18
Geriatric Depression Scale -7.52 5.40 .17
Daily Medication Use -2.07 14.50 .89
Timed Up and Go Test -14.30 6.00 .02
Summary and Conclusions • For women with mildly painful OA, momentary
fatigue may increase more disproportionately through the day than pain, particularly in those with higher disability (more pain)
• In addition to pain, increased momentary fatigue is associated with decreased physical activity
• Interventions to increase physical activity and manage symptoms in leg osteoarthritis may need a better emphasis on fatigue
Murphy SL et al. Arthritis Rheum 2008
Part 1 B: Behavioral Intervention• Current exercise programs for OA limited in their
link to activity or environmental context, nor are they designed to reduce individual barriers to PA and improve symptom control
• Hypothesis: Compared to those randomized to group exercise
and health education, can group exercise plus activity strategy training (AST, an OT approach) more effectively improve pain, fatigue, and physical activity?
• Design:– 1 month intervention with 2 and 4 month boosters– 6 month follow-up
Baseline Characteristics
EX + ED(n=26)
EX + AST (n=28)
P value
Age (years) 74.8 (7.3) 75.8 (7.1) .65
No. of women (%) 22 (85) 26 (93) .33
BMI (kg/m2) 30.0 (4.8) 30.1 (6.5) .98
No. of chronic conditions 1 (1.2) 1.5 (1.4) .17
No. of painful joints 4.6 (2.1) 4.4 (2.1) .79
(Murphy SL et al, Arthritis Rheum, in press)
EX+ED EX+AST
Pain and Fatigue Symptoms in OA PatientsPre and Post Intervention
0
2
4
6
8
PRE POST
fatigue
pain
Fatigue - Brief Fatigue Inventory, severity subscale; Pain – WOMAC pain subscale
Pain (time) p<0.005
Fatigue (time x group) p<0.05
Trend for fatigue to decrease in AST and increase in ED
Daily Peak Activity
600
640
680
720
760
Pre-Intervention Post-Intervention
Activ
ity C
ount
s
EX+ED EX+AST
Activity counts – collected via wrist-worn accelerometry (Actiwatch, MiniMitter-Respironics)
Trend for peak activity to increase in AST and decrease in ED
(time x group) p<0.05
Summary and Conclusions
• Compared to controls. participants in a group exercise plus activity strategy training designed to reduce individual barriers to PA and improve symptom control had:– Reductions in pain– Reductions in fatigue– Improvements in peak physical activity
Part II: Task-specific oxygen uptake and self-reported fatigue in older adults
• Global question: How does aerobic function relate to: – mobility performance?– symptoms of exertion and fatigue?
• A: Analysis of peak V02 versus submaximal oxygen kinetics in predicting mobility performance.
• B: In Type 2 diabetics, analysis of VO2 during peak GXT, submax, and six minute walk (6MW) in predicting perceived exertion (RPE) and fatigue
Background and Significance
• Age- and disease-associated declines in aerobic capacity (VO2 Max) contribute to functional disability in older adults.
• Standard VO2 measures may be limited– Max VO2 (e.g. max treadmill) is difficult to
achieve in older adults– Peak VO2 is frequently reported
Background and Significance (2)
• The aerobic demands of many ADL’s are submaximal
• Measures of submaximal (vs maximal or peak) aerobic fitness might:– Be easier and safer to perform, especially
for frail older adults– Better predict functional ability
Oxygen Kinetics in Healthy and Mobility Impaired Older Women
0 180 360 540 720 900
Time (seconds)
Healthy Woman
RestWalking (1.0 mph) Recovery
(63.7 mL)
(944.1 mL)
0
200
400
600
800
1000
Oxy
gen
Upt
ake
(mL/
min
)
O2 Deficit
O2 Debt
0 180 360 540 720 900
Time (seconds)
Mobility Impaired Woman
RestWalking (1.0 mph) Recovery
(873.0 mL)
(1734.4 mL)
0
200
400
600
800
1000
Oxy
gen
Upt
ake
(mL/
min
)
O2 Deficit
O2 Debt
Mean (SEM) Comparisons: Aerobic Unimpaired (n=21) vs Impaired (n=20)
Unimpaired Impaired
Age (yrs) 76 (1) 82 (1)*
Peak VO2 (ml/kg/min) 24 (1) 14 (1)*
TCdeficit (s) 23 (3) 58 (9)*
TCepoc (s) 40 (7) 57 (7)
Get up + Go (s) 12 (1) 20 (2)*
6-min-walk (m) 415 (17) 286 (27)*
*p<0.05
(Alexander, J Gerontol, 2003)
Tcdeficit => Initial oxygen deficitTcepoc => Excess post-exercise oxygen
consumption
Peak VO2 and Oxygen Kinetics versus Functional Performance: Unimpaired Old
Task Peak VO2 tcdeficit tcEPOC Peak VO2 0.62** 0.29
GUG 0.48* 0.58* 0.06
GUG x 3 0.55* 0.60** 0.13
Bag Carry 0.29 0.22 0.59**
Six Min Wk 0.45* 0.31 0.15
** p<0.01; * p<0.05 (Alexander, J Gerontol, 2003)
Peak VO2 and Oxygen Kinetics versus Functional Performance: Impaired Old
Task Peak VO2 tcdeficit tcEPOC Peak VO2 0.11 0.49*
GUG 0.21 0.10 0.42
GUG x 3 0.41 0.02 0.33
Bag Carry 0.35 0.07 0.53*
Six Min Wk 0.62** 0.18 0.64**
** p<0.01; * p<0.05 (Alexander, J Gerontol, 2003)
Summary and Conclusions• Older adults with aerobic impairment have:
– Slowed submaximal oxygen kinetics– Poor functional mobility performance
• Measures of submaximal oxygen kinetics correlate as highly with functional mobility performance as Peak VO2 measures, particularly for impaired old during post-exercise recovery.
• Submaximal VO2 kinetics may be more useful than Peak VO2 in estimating the contribution of aerobic function to mobility impairment.
Type 2 Diabetics[Enrolled in RCT ex program, age >60, n=56 [27 female]
Mean (SD) Range
Age (years) 70.4 (5.7) 60-83
BMI 33.6 (5.9) 24-50
EPESE total 1.0 (1.2) 0-6.0
BFI (global) 2.0 (1.8) 0-7.3
BFI (severity) 2.9 (2.2) 0-8.3
6MW dist (feet) 1264.5 (229.6) 660-1960
Comf Gait Sp (m/s) 1.2 (0.2) 0.8-1.5
Oxygen Uptake (VO2) Measurements
Three tasks:Graduated treadmill
(traditional peak)Submaximal treadmill
(1 MPH)Six minute walk
Self Report Measurements
During exercise task:• Rated Perceived Exertion (RPE): How hard
you worked– Range 6-20; 11=fairly light; 13=somewhat
hard; 15=hard; 17=very hard• Fatigue: How much fatigue you had
– 0=No fatigue; 10=Fatigue as bad as could be
0
5
10
15
20
25
Peak VO2 During TaskSubmax6MWGXT
Mean(SD)
OxygenUptake
(ml/kg/min)
*
*
*
0
5
10
15
20
Post-Task Rate of Perceived Exertion (RPE) Submax6MWGXT
Mean(SD)RPE
Score
0
5
10
15
20
25
Peak VO2 During TaskSubmax6MWGXT
Mean(SD)
OxygenUptake
(ml/kg/min)
*
*
*
0
1
2
3
4
5
6
7
8
Fatigue Post-TaskSubmax6MWGXT
Mean(SD)
FatigueScore
*
*
*
Self-reported task-specific fatigue is not related to general fatigue
Fatigue during task GXT Submax 6MW BFI global 0.12 0.18 -0.04 BFI severity 0.12 0.07 -0.11 Submax fatigue 0.52* 0.50* 6MW fatigue 0.39* 0.50* GXT fatigue 0.52* 0.39*
Non-GXT task-related fatigue may better relate to usual mobility function
Fatigue during task GXT Submax 6MW BFI global 0.12 0.18 -0.04 BFI severity 0.12 0.07 -0.11 EPESE 0.14 0.32* 0.16 TUG 0.28* 0.31* 0.16 Comf Gait Sp -0.25 -0.32* -0.22 6MW dist -0.14 -0.47* -0.32*
Task specific self-reported fatigue relates more to VO2 kinetics than peak VO2
Fatigue during task GXT Submax 6MW Peak GXT VO2 -0.12 Peak Submax VO2 -0.04 Peak 6MW VO2 -0.05 Submax Tc deficit 0.15 Submax Tc EPOC 0.34* 6MW Tc deficit 0.33* 6MW EPOC 0.39*
Summary and ConclusionsIn this group of relatively functional older adult
Type 2 diabetics:• Peak VO2 and post-task fatigue increase with
task demand• Self-reported task-specific fatigue is not
related to general fatigue• Non-GXT task-related fatigue may better
relate to usual mobility function• Task specific self-reported fatigue relates
more to VO2 kinetics than peak VO2
Discussion• Measures acquired during submaximal exercise
tests, including 6MW, as opposed to peak GXT, are better indicators of physical function, and likely fatigue.
• Future studies should consider:– Whether these relationships hold true for
other models of disability and fatigue (such as in non-cardiac disease, high baseline fatigue)
– What the underlying physiological link is between subjective fatigue and objective measures of oxygen utilization
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