Abstract
Amputation of a limb may affect quality of life. However, little is known concerning health-related quality of life in amputees. The purposes of this study were to describe health-related quality of life in a population of lower limb amputees and to investigate potential determinants, including phantom pain. Data from 437 patients with a lower limb amputation were analyzed in this cross-sectional study. Amputation-related problems were investigated using a questionnaire. Health-related quality of life was investigated using the RAND-36 DLV. Amputees with phantom pain had a poorer health-related quality of life than amputees without phantom pain. In general, the most important amputation-specific determinants of health-related quality of life were ‘walking distance’ and ‘stump pain.’
Keywords
Introduction
Amputation of a limb may be needed to treat critical ischemia, severe tissue damage due to a trauma, or a life-threatening condition of a limb. Although amputation can be beneficial from a medical point of view, the loss of a limb may have a considerable impact on the patient's health-related quality of life. Although health-related quality of life in amputees has been investigated in several studies, most describe specific and selected groups.
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Most studies have been focused on the comparison between amputation and limb salvage. Some of these study results favor limb salvage1
and some favor amputation9
or found no clear difference.13
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Lerner et al.
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reported that 17 of the 20 amputees in their study believed that they were ‘mentally scarred,’ but it was also reported that these subjects showed only limited restrictions in lifestyle and activity. Another study used the Nottingham Health Profile to measure health-related quality of life in lower limb amputees (n = 149), and found it to be poor.20
Smith et al.21
investigated health-related quality of life in a small group (n = 20) of unilateral below knee amputees using the RAND-36. In this study, it was found that health-related quality of life in the amputees was lower than in age-matched controls for the domains ‘physical function,’ ‘role limitations due to physical problems,’ and ‘pain.’ Until now, no study of health-related quality of life has assessed a broad group of amputees.Determinants of Health-Related Quality of Life in Amputees
Determinants of health-related quality of life in amputees have been explored in several studies. Lerner
19
, 22
found that timing of amputation can be a determinant of health-related quality of life: amputees with a primary amputation (n = 7) had a poorer adjustment, scored on the Psychosocial Adjustment to Illness Scale (PAIS), than amputees with a delayed amputation (n = 13). In contrast, Fairhurst16
found that early amputees (n = 4) had a higher health-related quality of life score as compared with late amputees (n = 8). Sound conclusions from these studies are probably not valid because of the very small number of patients included. Pell et al.20
found in lower limb amputees that health-related quality of life is decreased, mainly due to mobility problems. This finding is consistent with the results of a study by Weiss et al.23
These authors reported that the ability to do daily activities is the most important determinant of health-related quality of life in a group of veteran amputees. Walters and Williamson24
reported that sexual satisfaction is a determinant of health-related quality of life in amputees.Another potential determinant of health-related quality of life in amputees is phantom pain. Phantom pain can be defined as painful sensations in the amputated limb. Reported estimates of prevalence of phantom pain in patients with an acquired amputation range between 49–78%.
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Although it is recognized that phantom pain may have a considerable impact on employment, and interfere with sleep and daily activities,26
information concerning the association between phantom pain and health-related quality of life in amputees is very scarce. McCartney et al.27
found that the prevalence of phantom pain and phantom sensations in a small group (n = 40) of lower limb amputees was 77.5%, but only 10% of the subjects were limited because of the phantom pain. In the study of Lerner et al.,19
no difference in PAIS score was found between amputees with pain (n = 13) and amputees without pain (n = 7). No information concerning the type of pain was given in this publication. These results suggest that phantom pain has a small impact on health-related quality of life.The purposes of this study are 1) to describe health-related quality of life in lower limb amputees, and 2) to investigate potential determinants of health-related quality of life, including phantom pain, in lower limb amputees.
Methods
Subjects
Subjects with a lower limb amputation were identified in the database of an orthopedic manufacturer (OIM, Haren, The Netherlands). This database includes patients who were referred by their physician to the orthopedic manufacturer since 1 January 1993 with a lower limb amputation. The orthopedic manufacturer sent a letter to all subjects who were registered as having a lower limb amputation in the database since 1993 (n = 1436), which requested participation in this study. Positive replies were given by 536 (37%) subjects. These subjects were asked to fill out two questionnaires. Of this group, 437 (82%) subjects returned the questionnaires.
Questionnaires
The following self-administered questionnaires were used:
The Groningen Questionnaire Problems Leg Amputation (GQPLA) is a modified version of the questionnaire we used in an earlier study in arm amputees.
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This questionnaire contains, beside demographic questions, questions regarding the presence and frequency of phantom sensations, phantom pain, and stump pain. It also asks about walking distance (with a prosthesis). The following variables were taken as potential determinants of health-related quality of life: sex, age, presence or absence of phantom pain, stump pain and phantom sensations, level of amputation, walking distance, and bilateral amputation.The RAND-36 Dutch Language Version (RAND-DLV)
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is a Dutch version of the SF-36.29
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This questionnaire contains the following domains: ‘physical functioning,’ ‘social functioning,’ ‘role limitation due to physical problems,’ ‘role limitation due to emotional problems,’ ‘mental health,’ ‘vitality,’ ‘pain,’ ‘general health perception,’ and ‘health change.’ Additionally, the mean RAND-36 DLV score was calculated by summation of the domain scores divided by 9. All domains and the mean score have a scoring range of 0–100. A high score reflects a high health-related quality of life.Statistical Analysis
Statistical analysis was performed using SPSS version 9.0 for Windows. In case of missing values in the RAND-36 DLV, the individual mean domain value was used when less than 50% of the questions in the domain were missing. When more than 50% of the questions in a domain were missing, the domain of this case was excluded from the analysis, as recommended in the manual of the RAND-36 DLV.
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Potential determinants of health-related quality of life were analyzed using forward linear multiple regression analysis, with the mean score of the RAND-36 DLV and the separate RAND-36 DLV domains as dependent variables. The independent variables are summarized in Table 1.
Table 1Independent Variables Entered in the Regression Analysis and Their Codes
| Variable | Code |
|---|---|
| Sex | 0 = male |
| 1 = female | |
| Age | Years |
| Phantom pain | 0 = absent |
| 1 = present | |
| Stump pain | 0 = absent |
| 1 = present | |
| Phantom sensations | 0 = absent |
| 1 = present | |
| Level of amputation | 0 = below or through the knee |
| 1 = above the knee | |
| Walking distance | 0 = 500 meters or more |
| 1 = 0–500 meters | |
| Bilateral amputation | 0 = no |
| 1 = yes | |
| Amputation reason | |
| Vascular disease | 0 = no; 1 = yes |
| Diabetes | 0 = no; 1 = yes |
| Trauma | 0 = no; 1 = yes |
| Cancer | 0 = no; 1 = yes |
Differences in health-related quality of life between the subjects with phantom pain and those without phantom pain were analyzed using linear regression analysis by the enter method. We considered that age, sex, level of amputation, bilateral amputation, and amputation reason may influence health-related quality of life. Therefore, we corrected this comparison for these factors by entering these in the regression analysis. Differences between amputees with phantom pain and amputees without phantom pain were analyzed with the Mann-Whitney test in case of ordinal scales. For all analyses, a P-value <0.05 was considered statistically significant.
Results
Demographic characteristics of the group are listed in Table 2. In Table 3, the number of missing answers for several questions and domains are listed.
Table 2Demographic Data
| Age, mean (SD) years | 65 (15) |
|---|---|
| Time since amputation, median (min–max), years | 10 (1–80) |
| Sex, male/female | 71%/29% |
| Bilateral amputation prevalence | 10% |
| Phantom pain prevalence | 80% |
| Phantom sensations prevalence | 86% |
| Stump pain prevalence | 68% |
| Amputation reason | |
| Trauma | 34% |
| Vascular disease | 29% |
| Diabetes | 21% |
| Cancer | 9% |
| Congenital | 2% |
| Other | 5% |
| Amputation level | |
| Below knee | 61% |
| Above or through knee | 39% |
| Prosthesis use at home | 96% |
| Prosthesis use outside | 95% |
| Walking distance | |
| one kilometer or more | 29% |
| 500 meters–1 kilometer | 18% |
| 100–500 meters | 26% |
| less than 100 meters | 27% |
Table 3Completion Rates of the Questionnaires (n = 437)
| Missing | ||
|---|---|---|
| (n) | (%) | |
| Age | 18 | 4 |
| Time since amputation | 32 | 7 |
| Sex | 10 | 2 |
| Bilateral amputation | 0 | 0 |
| Phantom pain present | 45 | 10 |
| Phantom sensations present | 28 | 6 |
| Stump pain present | 62 | 14 |
| Amputation reason | 4 | 1 |
| Amputation level | 3 | 1 |
| Walking distance | 33 | 8 |
| RAND-36 DLV Domains | ||
| Physical functioning | 71 | 16 |
| Social functioning | 15 | 3 |
| Role limitation due to physical problems | 94 | 21 |
| Role limitation due to emotional problems | 100 | 23 |
| Mental health | 42 | 10 |
| Vitality | 44 | 10 |
| Pain | 19 | 4 |
| General health perception | 21 | 5 |
| Health change | 9 | 2 |
Determinants of Health-Related Quality of Life in Amputees
Significant differences, corrected for age, sex, level of amputation, and bilateral amputation, were found between amputees with phantom pain and amputees without phantom pain for the RAND-36 DLV domains ‘role limitation due to emotional problems’, ‘vitality’, ‘pain’, ‘general health perception’, and the mean RAND-36 DLV score (Table 4).
Table 4Mean Differences and 95% Confidence Intervals (CI) in RAND-36 DLV Scores Between Amputees with Phantom Pain and Amputees Without Phantom Pain
| RAND-36 DLV Domains | Mean (SD) Scores | Mean Difference Between Amputees With and Without Phantom Pain | 95% CI of the Mean | P value |
|---|---|---|---|---|
| Physical functioning | 43 (29) | −6 | −13 to 1 | 0.094 |
| Social functioning | 74 (28) | −5 | −13 to 2 | 0.148 |
| Role limitation due to physical problems | 47 (43) | −6 | −18 to 5 | 0.263 |
| Role limitation due to emotional problems | 70 (41) | −14 | −25 to −2 | 0.019 |
| Mental health | 76 (19) | −4 | −9 to 1 | 0.144 |
| Vitality | 63 (22) | −7 | −13 to −2 | 0.014 |
| Pain | 71 (26) | −21 | −28 to −15 | <0.001 |
| General health perception | 64 (23) | −7 | −12 to −1 | 0.025 |
| Health change | 50 (20) | −2 | −7 to 4 | 0.520 |
| Mean RAND-36 DLV score | 64 (19) | −7 | −12 to −1 | 0.013 |
a Corrected for age, sex, level of amputation, bilateral amputation, and amputation reason. Mean differences are the coefficients from the linear regression analysis; a negative sign indicates that the score of the amputees with phantom pain is lower as compared with amputees without phantom pain.
The median walking distance of amputees with phantom pain was 100–500 meters. The median without phantom pain was 500–1000 meters. This difference is statistically significant (Mann-Whitney: P < 0.001).
Forward linear regression analysis revealed equations for the different RAND-36 DLV domains (Table 5). In 8 of the 9 equations, the variables ‘walking distance’ and ‘stump pain’ appeared to be a significant factor.
Table 5Regression Equations and Explained Variance for the Different RAND-36 DLV Domains and the Mean RAND-36 DLV Score
| RAND-36 DLV Domains | Equation | Explained Variance (%) |
|---|---|---|
| Physical functioning | 86.7 − 29.5(walking distance) − 6.6(stump pain) − 0.45(age) + 7.0(gender) | 48 |
| Social functioning | 79.2 − 15.3(walking distance) − 8.6(stump pain) + 10.5(gender) + 6.3(level of amputation) | 16.5 |
| Role limitation due to physical problems | 80.1 − 31.8(walking distance) − 11.1(stump pain) − 22.5(diabetes) − 11.7(vascular disease) | 27.4 |
| Role limitation due to emotional problems | 89.0 − 21.1(walking distance) − 14.6(stump pain) + 12.8(level of amputation) | 13.8 |
| Mental health | 84.6 − 10.2(walking distance) − 7.9(stump pain) + 5.6(level of amputation) | 13.2 |
| Vitality | 76.7 − 11.2(walking distance) − 10.4(stump pain) | 12.4 |
| Pain | 98.0 − 13.0(walking distance) − 15.0(stump pain) − 13.0(phantom pain) | 23.8 |
| General health perception | 80.5 − 13.0(walking distance) − 6.8(stump pain) − 17.3(diabetes) | 22.9 |
| Health change | 55.9 − 5.1(stump pain) − 6.7(diabetes) | 2.9 |
| Mean RAND-36 DLV Score | 80.2 − 15.8(walking distance) − 9.3(stump pain) − 8.0(diabetes) | 28.7 |
Sex: 0 = male, 1 = female; age: years; phantom pain: 0 = absent, 1 = present; stump pain: 0 = absent, 1 = present; level of amputation: 0 = below the knee, 1 = above or through the knee; walking distance: 0 = 500 meters or more, 1 = 0–500 meters; bilateral amputation: 0 = no, 1 = yes; amputation reason: diabetes: 0 = no, 1 = yes, vascular disease: 0 = no, 1 = yes, trauma: 0 = no, 1 = yes, cancer: 0 = no, 1 = yes.
Discussion
Our study indicates that amputees with phantom pain have a considerably poorer health-related quality of life than amputees without phantom pain. The most important amputation-specific determinants of health-related quality of life in lower limb amputees were ‘walking distance’ and ‘stump pain.’
Although phantom pain is recognized as a frequent problem in amputees, until now the relationship between phantom pain and health-related quality of life has been investigated in very few studies. The results of our study show for the first time that health-related quality of life is poorer in amputees with phantom pain than amputees without phantom pain. The largest difference in health-related quality of life between amputees with phantom pain and amputees without phantom pain was found, besides in the domain ‘pain,’ in the domain ‘role limitation due to emotional problems’. In this domain, amputees with phantom pain score on the average 14 points lower, on a range of 0–100, as compared with amputees without phantom pain.
The finding that health-related quality of life is lower in amputees with phantom pain as compared with amputees without phantom pain is in contrast with the results of the study of Lerner et al.
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The study of Lerner et al. was, however, limited to only 20 subjects and no information was given about the type of pain. The results of our study do not support the suggestion by McCartney et al.27
that phantom pain has a small impact on health-related quality of life. The results of our study indicate that phantom pain deserves more attention in the rehabilitation of amputees.The relationship between phantom pain and emotional problems was investigated earlier by Arena et al.
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These authors observed three different relationships between phantom pain and stress: an isomorphic relationship (same time increases in pain lead to same time increases in stress and vice versa), a consequence relationship (increases in pain precede increases in stress), and a precursor relationship (increases in stress precede increases in pain). This is consistent with the findings in a study by Magni et al.33
in subjects with chronic musculoskeletal pain. These authors found support for two relationships: depression may promote chronic pain and chronic pain may promote depression. It is likely that phantom pain induces poor health-related quality of life like emotional problems. On the other hand, it is also possible that poor health-related quality of life, for instance due to emotional problems, induces phantom pain.Differences in health-related quality of life between amputees with and amputees without phantom pain can also, at least partly, be explained by the difference in walking distance. Walking distance appears to be higher in those without phantom pain as compared with amputees without phantom pain. Because health-related quality of life, phantom pain and walking distance are all related, phantom pain and walking distance are confounders in their relation to health-related quality of life.
The results of the linear regression analysis to predict health-related quality of life in amputees show that the explained variance is low except for the domain physical functioning. Apparently, health-related quality of life is only to a small part determined by amputation-specific factors. The relatively high explained variance for the domain ‘physical functioning’ can be explained by the fact that many questions in this domain are related to walking problems. The most important determinant of the different RAND-36 DLV health-related quality of life domains is in our study ‘walking distance.’ This factor is present in all equations except the one to predict ‘health change’. For the other health-related quality of life domains, the scores are 10.2–31.8 lower in the amputees with a walking distance less than 500 meters as compared with the amputees with a walking distance more than 500 meters. This suggests that impaired walking distance may contribute to poor health-related quality of life. In patients with chronic airflow limitation, it was also found that walking distance is related to health-related quality of life, as measured using the Sickness Impact Profile.
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It also suggests that it may be worthwhile to focus rehabilitation on increase in walking distance.Remarkably, the factor ‘amputation level’ appeared to be a determinant of the RAND-36 DLV domains ‘social functioning’, ‘role limitation due to emotional problems’, and ‘mental health’ in the sense that subjects with an amputation through or above the knee have a somewhat higher health-related quality of life as compared to those with a below knee amputation. The explanation for this finding is not clear but the significance may be due to chance.
Stump pain appears to be a determinant of health-related quality of life in amputees. Health-related quality of life (RAND-36 DLV) scores in subjects who report stump pain are 5.1–15.0 points lower than those not reporting stump pain. Stump pain may be a more important determinant of health-related quality of life than phantom pain.
A limitation of our study is that selection bias may have influenced our results because only subjects who were referred to the orthopedic manufacturer were included.
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Although we did not select patients on the basis of prosthetic fitting, 96% of the subjects used a prosthesis. In an earlier study in the north of The Netherlands, it was found that prosthetic fitting was achieved in only 48% of the lower limb amputees.36
This is in agreement with other studies.37
It is possible that subjects who were not referred to an orthopedic manufacturer have a poorer health-related quality of life and poorer survival. The minimal time since amputation in our study was 1 year. The results of our study are, therefore, limited to those subjects with a survival expectancy of at least one year. The five-year survival of subjects with a lower limb amputation due to end-stage vascular disease is estimated between 15–33%.38
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The database we used to identify subjects for this study included amputees who were referred to an orthopedic manufacturer since 1993. This very poor survival in the vascular disease amputees explains the low response rate and the relatively low proportion of amputees because of vascular problems (21%) and vascular problems secondary to diabetes (29%) in our study as compared to other studies. For instance, in an epidemiological study in lower limb amputees by Rommers et al.,36
the amputation reason in 94% of the patients was because of vascular disease, in 3% because of cancer, and in 3% because of trauma.Another limitation of this study is that a relatively high number of patients returned incomplete questionnaires, especially the domains ‘role limitation due to physical problems’ and ‘role limitation due to emotional problems.’ The rate of completion was lower as compared to a validation study of the SF-36 by Brazier et al.
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A potential explanation for this phenomenon is that patients in our group were older; 129 were in the age group 60–75 years and 35 were older than 75 years. It is possible that older patients have more problems filling in this kind of questionnaire than younger patients. Post-hoc analysis confirmed this hypothesis. Patients returning incomplete answers in the RAND-36 DLV domain ‘role limitation due to physical problems’ are considerably older (mean [SD] age: 75 [9] years) as compared to those who returned complete answers in this domain (mean [SD] age: 63 [15] years) (P < 0.001). The same difference was found for the domain ‘role limitation due to emotional problems.’In conclusion, the results of our study suggest that rehabilitation of amputees should be focused on reduction of stump pain and phantom pain, and an increase in walking distance.
Acknowledgments
This study was supported by a grant from the orthopedic manufactory OIM Haren, The Netherlands. The authors would like to thank Mr. A. Elzinga and Mr. M. van Dijk for their help with data collection.
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Accepted:
December 22,
2001
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