1 Physical Medicine and Rehabilitation, 2 Nephrology and 3 Renal Transplantation, Université Catholique de Louvain, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Abstract |
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Methods. Using the Baecke self-administered and the Five-City Project 7-day PA recall questionnaires, PA level was estimated in 32 consecutive ESRD patients (12 males, 20 females; mean age 45.9±13.1 years; mean dialysis duration 23.5±21.8 months) admitted for renal TP and to whom no exercise programme of any kind was proposed. PA were recorded 1, 3, 6, 12 and 60 months after TP.
Results. Immediate pre-TP PA level of renal transplant candidates was between 18 and 35% less than that of age-matched healthy subjects (P<0.05), depending on gender and questionnaire. After an immediate decrease in PA level 1 month post-TP, mean PA level increased and reached a plateau 1 year after TP. This gain in PA capacity reached 30%, as compared with pre-TP values (P=0.06 to P<0.01). During the fifth year after TP, the mean level of PA was unchanged. A more qualitative analysis, allowed by the sub-score comparisons, showed that although the occupational status of the patients remained the same, they participated significantly more in moderate and even high intensity PA (leisure, sports, household chores) after TP.
Conclusions. Most renal graft recipients are spontaneously more active after TP, an observation consistent with a better quality of life. Therefore, they should be advised precisely about how to resume more strenuous activities such as sports in order to avoid cardiac or musculoskeletal disorders in relation to their weakened pre-TP condition.
Keywords: haemodialysis; physical-activity; questionnaires; rehabilitation; renal-transplantation
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Introduction |
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Very few data are available for PA level of end-stage renal disease (ESRD) patients on regular haemodialysis (HD) [3,4]. A low PA level is expected in these patients since a decreased functional status has been demonstrated with the Karnofsky scale or the Sickness Impact Profile [57] and since low physical fitness has been reported [8]. Data about the PA level of patients who have undergone renal transplantation (TP) are equally scarce [3,9,10]. Such patients would be expected to be more active than prior to TP since their uraemic syndrome is corrected and they don't have to spend 12 h a week on HD treatment. On the other hand, both surgery and steroids administration, with its attendant deleterious effect on muscle metabolism [11] and bone mass [12], are expected to negatively affect rehabilitation.
In order to elucidate the net impact of TP on PA in both the short and long term, we prospectively recorded PA level using two validated questionnaires administered to a population of transplanted patients to whom no exercise programme of any kind was proposed.
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Subjects and methods |
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Age at inclusion averaged 46.2±9.50 and 46.1±15.30 years for males and females, respectively. Their respective mean weight was 70.3±7.8 kg and 57.6±9.8 kg, with mean body mass indices (BMI) of 23.6±1.93 kg/m2 and 22.4±4.13 kg/m2 for males and females, respectively. Thirty-one patients were on regular HD before TP for a mean duration of 22.5±21.65 months; one patient had a pre-emptive living-donor TP. The graft originated from a cadaver donor in 29 cases and from a living related donor in three cases. At the time of admission for TP, mean creatinine and haemoglobin were 8.9±2.3 mg/dl and 10.0±1.6 g/dl, respectively. Twenty-three patients were on erythropoietin therapy. Pre-transplant-associated co-morbid conditions were diabetes mellitus (n=2) and a previous history of cerebral aneurysm rupture (n=1). All patients underwent immunosuppression with 500 mg i.v. methylprednisolone at induction and oral prednisolone. In addition, 21 patients were given cyclosporine and azathioprine, three patients cyclosporine and mycophenolate mofetil, and eight patients tacrolimus and azathioprine. Rejection episodes were treated with three i.v. boluses of 500 mg methylprednisolone. If they proved resistant, a 10-day course of ATG or OKT3 (Orthoclone®, Cilag Ortho Pharmaceutical Corporation, Raritan, NJ, USA) was given. In the patients for whom anti-hypertensive drugs were necessary after TP, they were prescribed in the following sequence: calcium antagonist, beta-blocker, ACE inhibitor, diuretic.
PA level and weight were measured in all patients 1, 3, 6 and 12 months after TP (t1, t3, t6 and t12) as well as during the fifth year after TP (t60). At t60, only 18 patients (nine males, nine females) were available for evaluation. Among the drop-outs, one was lost to follow-up, three had resumed HD, three had died (one sepsis, one anorexia nervosa and one unknown) and seven declined the final evaluation.
PA level evaluation
PA level was determined by both the Baecke [13] and a 7-day recall (the Five-City Project) questionnaires [14], translated into French. Both questionnaires were administered by the same well trained observer for every patient at all six evaluations.
Patients were questioned within the first 15 days following TP about the 1-week period immediately preceding their admission (t0). This period was assumed to be representative of their habitual PA before TP.
The Baecke self-administered habitual PA questionnaire
The questionnaire was self-administered although, if necessary, active help from the observer was provided. This questionnaire allows calculation of a total PA score, which is the sum of three separate sub-scores (leisure time, sport and occupation). It generally refers to habitual PA. Each evaluation allowed the calculation of four different PA scores: a total PA score (Btot0,...60), a sport-related PA sub- score (Bsport0,...60), a leisure-time-related PA sub-score (Bleisure0,...60) and an occupation-related PA sub-score (Boccup0,...60).
The Five-City Project 7-day recall PA questionnaire
This questionnaire allows calculation of five PA sub-scores: the total amount of time spent per week in sleep or rest (Rest0,...60), and in light intensity (Light0,...60), in moderate intensity (Mod0,...60), in hard intensity (Hard0,...60) and in very hard intensity (Vhard0,...60) PA. All these sub-scores are expressed in hours/week. One MET is defined as the energy expenditure rate for sitting quietly and approximates resting metabolic rate (1 kcal/h/kg). Sleeping or resting, and light, moderate, hard and very hard intensity PA correspond to 1, 1.5, 4, 6 and 10 MET for energy consumption calculation [14] with the Five-City Project questionnaire. To record and classify some activities that were not present on the questionnaire's list, we used the Compendium of Physical Activities from Ainsworth et al. [15]. HD time (12 h/week) was arbitrarily considered as bed rest.
The total Five-City Project PA score (5CPtot0,...60) is obtained by summing the five sub-scores, which have been multiplied by their corresponding intensity level (in MET), and dividing by seven (days/week). These scores thus represent the average daily energy expenditure rate of the preceding week, expressed in kcal/day or in kcal/day/kg body weight, when normalized for body weight.
Analysis
Mean patient weights at t0, t3, t6, t12 and t60 were analysed by analysis of variance (ANOVA) for repeated measures. As an effect of treatment (TP) on weight is demonstrated, the comparisons between pre- and post-TP mean weights were performed using Student's paired t test.
Baseline PA scores obtained with both questionnaires were compared with those of age- and sex-matched healthy subjects [14,16,17], using unpaired Student's t test.
ANOVA for repeated measure was conducted on all PA scores with gender as a possible interacting factor. When no gender effect was present, further analysis was conducted on all patients as a single group. When a significant effect of treatment (TP) on PA level was demonstrated, comparisons between pre- and post-TP scores obtained with both questionnaires were performed using Student's paired t test.
The Spearman r correlation coefficient between baseline total PA scores obtained with both questionnaires was calculated to question the validity of the methodology. For statistical analysis, the significance level was defined as P<0.05.
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Results |
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Table 3 presents all Five-City Project PA sub-scores (mean±SD) expressed in hours spent weekly for patients before TP, as well as for controls. Data for healthy subjects were re-calculated from Sallis et al. [14] after exclusion of elderly subjects (6574 years). Mean Rest0 was 50% greater in HD patients of both sexes. Mean Light0 was significantly reduced in females (P<0.01) but not in males (P
0.10). None of the 32 uraemic subjects recalled any very hard PA. This observation is probably particularly relevant in males since the data from Sallis et al. [14] indicate that healthy males spend an average of 2.3 h/week at very hard PA. Other mean sub-scores (Moderate0 and Hard0) for HD patients were lower, but not significantly different from those of healthy controls.
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The Spearman correlation coefficient calculated between pre-TP Btot0 and 5CPtot0 was 0.60 (P=0.0002).
ANOVA of PA scores obtained with both questionnaires at t0, t1...t60 demonstrated a significant (P<0.0001) effect of treatment (TP). The fact that no gender interaction (P=0.26) was observed allowed us to treat all patients as a single group for further analysis. Figure 2 shows mean Btot (Figure 2a
) and 5CPtot (Figure 2b
) at t0, t1...t60, expressed in kcal/day/kg. Mean Btot was significantly decreased at t1 and t3; in contrast, the decrease of mean 5CPtot at t1 was not significant. A statistically significant increase of PA level was observed at t6 for 5CPtot, and at t12 and t60 for both PA scores. One year after TP (t12), mean Btot12 was 6.7±1.9 and 5.5±2.4, which represents an increase of 14 and 15% as compared with t0 in males and females, respectively. Mean 5CPtot12 was 36.1±3.16 and 34.6±3.86 kcal/day/kg in males and females, which is an increase of 8 and 7% in males and females, respectively. At 12 months post-TP, all total PA scores, with the exception of female Btot12, (male Btot12, and male and female 5CPtot expressed in kcal/day) were no more significantly different from those of healthy subjects. However, to reflect PA level more objectively, 5CPtot scores ought to be expressed in kcal/day/kg, as will be discussed further.
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Table 4 shows the mean Baecke (±SD) sub-scores at t0, t12 and t60. Mean Bsport and Bleisure sub-scores increased significantly 1 and 5 years after TP, whereas Boccup remained virtually unchanged. At t0, only 11 out of the 32 patients had an occupation. After TP, the employment rate remained exactly the same.
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Discussion |
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A significant progressive weight gain was demonstrated in all subjects after TP; it was already present at t6 and remained approximately stable later on. At t12, it averaged 10% in males and 9% in females, as compared with t0, while their respective pre-TP mean BMI were within the normal range. A similar post-TP BMI increase was also observed by Gallagher-Lepak as soon as 4 months after TP [3], which has been attributed to an increase in fat mass. This observation emphasizes that, if PA levels have to be monitored after TP, PA scores that are normalized for body weight (and thus expressed in kcal/day/kg) should be used, as we did with the Five-City Project.
Patients' PA was retrospectively assessed after they had been admitted for TP, making the questionnaire method of analysis the only one possible. The reliability of PA level assessment by questionnaires has been widely discussed [17]. Several well known questionnaires, including those used here, are certainly considered as valid and reliable [16,17]. The Baecke and the Five-City Project questionnaires question all types of PA: occupation, leisure time and sports. They were used together here since the information they allow us to collect are complementary: the Baecke allows a subjective recall of PA classified according to their nature (occupational, leisure, sports) while the Five-City Project gives a more objective and quantitative estimation of PA classified according to their intensities (rest, light, moderate, etc.). Although the Baecke questionnaire is commonly used and easy to administer, the subjective items it includes (i.e. after working I am tired or during leisure time I watch television, for which subjects have to score on a 5-point Likert scale ranging from never to always) probably leads to a more subjective, psychophysical, PA level assessment. This assumption is further supported by the greater dispersion of the Btot values: the variation coefficient calculated at t0 was 44.5% for Btot whereas it only reached 9.8% for 5CPtot. Both questionnaires were also chosen since they could be filled in easily within 30 min. The fact that total PA scores obtained with both questionnaires significantly correlate suggests that the PA assessment methodology in this study is valid.
If PA level has to be objectively quantified, the Five-City Project should be preferred since it constitutes in itself a rate of energy expenditure measurement. The fact that uraemic patients have to spend an average time undergoing HD of 12 h/week might be responsible for a significant reduction in the total PA score. The re-calculation of the mean 5CPtot at t0 after considering HD as a light PA (1.5 MET) instead of rest (1 MET) shows that pre-TP 5CPtot remains significantly reduced in males and females, as compared with healthy controls [14]. This suggests that uraemic patients have a significant reduction of their mean total PA level, probably in direct relation to their health status. Moreover, a shift from very hard and light intensity towards rest and sleep PA is observed in our patients, while mean time spent at hard and moderate intensity PA is not affected (Table 3). In this respect, HD patients behave like elderly subjects who are generally less active and avoid more strenuous PA.
Before TP, mean PA level of uraemic patients was significantly reduced compared with that of healthy subjects (Table 2). The PA level of the average dialysis patient is probably even affected to a greater extent, as suggested by others: transplant candidates are less inactive than patients who are not [6,7,18].
Immediately after TP, a decrease of mean PA level measured with the Baecke questionnaire is observed. Within 6 months, the PA level reached the pre-TP level again. At t12 and t60, mean Btot scores were significantly higher compared with pre-TP values. The initial decrease can be accounted for directly by the immediate post-surgery recovery and the occurrence of acute graft rejections or other medical complications in some patients.
Overall PA level evolution, estimated with the Five-City Project, was similar. However, it increased sooner after TP (Figure 2b). At t3, mean 5CPtot was already higher than that observed at t0, although the difference was not significant. At t6, the difference became significant and it was maximal at t12. It must be noted that the minimum PA score on the Five-City Project questionnaire is 24 kcal/day/kg, which corresponds to the value that would be recorded if a subject spent a whole week totally inactive (sleeping, for instance). Thus, with the zero of the 5CPtot scale being 24 kcal/day/kg, the relative 8 and 7% increases calculated at t12 for males and females, respectively, correspond to actual re-calculated increases of 31 and 27% obtained by subtracting 24 kcal/day/kg from the values shown in Figure 2b
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In the fifth year after TP, mean PA level remained significantly higher compared with baseline values. The actual re-calculated relative increase was 25 and 22% in males and females, respectively. This small decrease in PA level observed between t12 and t60 may be consistent with the physiological reduction of PA level that occurs with aging in healthy subjects in their forties over such a 5-year period.
Do HD patients recover a normal PA level after TP? Although the increase in PA level observed after TP is partly due to the fact that graft recipients did not spend 12 h/week on dialysis any longer, a more qualitative analysis of t0 and t12 Five-City Project sub-scores raised interesting issues (Table 5): at t12, patients spent significantly less time sleeping or resting compared with t0. They spend on average 5.5 h/week less sleeping or resting, which is only approximately half the amount of time dedicated to dialysis before TP. In other words, dialysis interruption alone can only partially explain the increase of mean PA level observed in our patients. Further analysis shows that, while the sub-score corresponding to light PA (Light12) remained unchanged, patients replaced most of their pre-TP dialysis time with mainly moderate intensity PA and also by a few hard intensity PAs (Table 5
). Hard activities reported by the subjects consisted of intense household tasks, gardening, home renovation and sports. At t12, one subject even reported 1.5 h/week of very hard sport participation. At t12, the mean significant total PA increase, reflected by the mean Btot increase, was mainly explained by a more extensive participation in moderate leisure and sports type of PA since employment rate remained the same after TP.
Hence, our data showed that TP not only makes 12 extra hours per week available for light activities, but also seems to provide most subjects with a healthier status that allows participation in moderate and hard intensity PA. These observations are thus consistent with a better quality of life that accompanies successful TP, although total PA level probably remains inferior to that of healthy subjects since the low employment rate (33%) was not modified after TP in this study.
Several authors evaluated different aspects reflecting quality of life after TP: health-related fitness, functional capacity, physical working capacity [3,1921]. Recently, Dew et al. [22] reviewed 218 independent studies focusing on quality of life after TP. They concluded that most studies showed significant post-TP improvements in functional indices of quality of life as PA level. However, most studies also showed that in general, graft recipients did not recover completely normal physical functioning after TP.
To our knowledge, only Gallagher-Lepak et al. have assessed PA level before and after renal TP using the Human Activity Profile [3]. They monitored self-reported activity level in nine patients before TP, and 6 weeks and 16 weeks after TP, and found that a significant increase in PA level was observed at 16 weeks. Our longer follow-up study, which included subjects to whom no rehabilitation programme was proposed, evaluates more quantitatively the long-term spontaneous PA level increase after TP. In some cases, organ transplant recipients are even capable of near-normal or even higher levels of physical functioning as compared with controls, as demonstrated by athletes who participated in the 1996 U.S. Transplant Games [19]. One must however keep in mind that ESRD patients present a significant weakening of cardiovascular and locomotor system as a direct consequence of renal failure and inactivity. Moreover, after TP, immunosuppressive drugs have a direct weakening effect on muscles [11] and bones [12]. This led some authors to hypothesize that an excessive PA performed immediately after TP might be responsible for the occurrence of epiphyseal impactions [23]. Patients should therefore be precisely advised to minimize the risk of locomotor injury post-TP. This could be achieved by systematically proposing exercise programmes individually tailored to the needs and condition of each patient. Such programmes have indeed be successfully applied to haemodialysis patients [24]. Shortly after TP, such programmes should also favour individual aerobic exercise of large muscles without excessive mechanical strains on bones and joints (stationary or outdoor cycling, swimming or walking). Miller et al. showed that such a supervised aerobic exercise regimen proposed to 10 selected patients after renal TP led to a 90% exercise capacity improvement after only 5.5 weeks [9]. Most of their patients (7/10) continued exercising regularly after the supervised programme was completed and they achieved normal exercise capacity within 8 weeks of TP. Later on, after normal physical capacity has been recovered, more intense sports participation (e.g. jogging, ball sports, etc.) may be considered.
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Notes |
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References |
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