The current study investigated sex differences in the pain experience of persons with limb loss. In this large survey sample, we found no significant sex differences in the presence or intensity of amputation-related pain (i.e., PLP and RLP). Female participants did, however, report greater overall pain intensity and pain interference relative to male participants, which is consistent with the literature. Based on biopsychosocial models of chronic pain and disability43
, several other domains of functioning were also examined in this study. The results indicated that females endorsed significantly greater pain catastrophizing and use of several adaptive and maladaptive pain coping strategies. Moreover, females with limb loss in the present study were significantly more likely to endorse several beliefs about pain that have previously been identified as predictors of poor adjustment to chronic pain29
Our hypotheses concerning sex differences in pain intensity were only partially supported. The lack of sex differences in PLP and RLP is consistent with previous, smaller studies that tested for sex differences in ancillary analyses14,32,36
. Taken together, these data suggest that sex differences are not a robust phenomenon in the context of amputation-related pain, particularly after accounting for any sex differences in the reason for amputation. In contrast, differences between male and female participants did emerge for general pain intensity, although this did not meet the strict statistical criterion (p <.01) adopted for this study. These results are also in line with the large literature indicating that females are more sensitive to experimental pain stimuli and are overrepresented among those who report clinical pain problems41,50
. To our knowledge, this is the first study to specifically test for sex differences in amputation-related and general pain in the same sample. As such, additional research is needed before strong conclusions can be drawn; however, it does appear that sex is a potentially important variable of consideration in the context of pain intensity in persons with limb loss.
Females in the current study also reported slightly greater pain interference in activities of daily living than males. In the broader, non-amputation pain literature, relatively little has been published about sex differences in pain-related functional impairment. The studies that have been reported to date have yielded mixed results1,5,17,38
. Sex differences in pain interference in persons with limb loss have received even less empirical attention. One study did examine the impact of limb amputation on multiple indices of quality of life and found that females reported worse status than males with respect to physical disability4
. However, that study did not assess functional impairment related to pain and, thus, cannot directly speak to the sex differences in pain interference observed in the current study. These two studies do suggest, however, that females may be particularly vulnerable to the negative functional consequences of pain and limb loss.
In the psychosocial domain, several notable similarities and differences emerged between male and female participants. Males and females reported similar levels of psychological functioning, which is inconsistent with the results of two smaller studies that examined this issue in persons with limb loss33,47
. The non-amputation pain literature also contains several studies in which females with chronic pain manifested greater negative mood than males11,37,59
; however, such sex differences are not always found7,17,43
. At this point, it seems premature to draw any strong conclusions about sex differences in mental health outcomes following amputation; further research is needed to better understand this relationship.
Consistent with our hypotheses, females reported greater pain catastrophizing than males. Previous research has found catastrophizing to be associated with negative mood and poorer adjustment to pain16,55
, including among persons with amputation-related pain13,20
; thus, the sex difference observed herein could be particularly important. These results are also in accordance with previous research in non-amputation samples that has found females with chronic pain report more frequent catastrophic cognitions than males35,55
. We are not aware of any research to date that has examined sex differences in pain catastrophizing in persons with limb loss. Although continued work in this area is warranted, the current data do suggest that females who have undergone limb amputation may manifest negative psychological sequelae to a greater degree than their male counterparts.
Also consistent with prior investigations19,59,60
, females in the current study endorsed greater use of several pain coping strategies compared to males. This greater use of pain coping strategies in general may be a consequence of females’ greater overall pain intensity. Several of the coping strategies that females endorsed to a greater degree than males are considered adaptive responses to pain and therefore encouraged, specifically those related to relaxation, pacing, and coping self-statements12,30
. However, females also reported more resting strategies, which are typically not adaptive. These sex differences in coping strategies are important, since it is understood that how one copes with pain – in particular, the frequency of maladaptive coping strategies – is an important determinant of adjustment to chronic pain10,26
. Building on the current results, future research could examine whether males and females with limb loss differentially evaluate the effectiveness of these various pain coping strategies, as such information could have valuable clinical implications.
Another important element of the biopsychosocial model of pain concerns an individual’s beliefs about the pain experience44
. There is a lack of previous theoretical and empirical work on the topic of sex differences in this area; thus, the current study makes a notable contribution to the literature. Female participants in the current sample endorsed greater beliefs regarding personal control over pain, the appropriateness of medication use for pain management, and the appropriateness of solicitous responses from others. With the exception of those concerning personal control over pain, these beliefs are associated with poorer adjustment to chronic pain29
. Females’ endorsement of greater beliefs regarding personal control over pain may be related to their more frequent use of a wide array of pain coping strategies, since individuals who view pain as controllable would be expected to attempt to exert such control via multiple coping strategies. These positive characteristics of female participants were unfortunately tempered by their greater maladaptive beliefs about pain, the effects of which may be particularly detrimental10,27
In the broadest sense, these data reaffirm the relevance of a biopsychosocial conceptualization of pain in persons with limb loss. Moreover, although not identical, the nature of the sex differences observed in this study were generally consistent with those found in other chronic pain conditions9
. Females with limb loss who experience chronic pain appear to be particularly susceptible to various negative sequelae of this condition. Two possible reasons for this increased risk in females with limb loss pertain to gender-specific socialization patterns40
and cultural norms surrounding beauty65
. Although not assessed in the current study, it is possible that differences in how males and females are expected to manage pain and negative mood influence their adjustment following amputation. In addition, the implications of permanent “disfigurement” may be very different for males and females, which may influence their experience of pain. Future research is needed to test these speculations.
Several limitations of the current study should be considered. First, those who responded to the survey (56% response rate) could differ in important ways from non-responders. Similarly, it is possible that the current sample is not representative of the overall population of individuals with limb loss. Second, the study sample lacked racial and ethnic diversity and, thus, may be less relevant to non-Caucasian individuals. Third, this study relied exclusively on self-report measures of pain and psychosocial variables, which may be subject to reporting bias. Fourth, due to the wording of the assessment instruments, we were not able to conduct a more fine-grained analysis of certain variables. For example, the pain interference measure did not specify whether this interference was due to amputation-related or general pain. Pain interference in each of these domains could be distinguished in future research with small modifications to the instrument instructions. Finally, out of consideration for participant burden, we assessed only a small number of psychosocial variables. These variables were selected because they were previously identified as important considerations in the context of sex differences, pain, and disability. Nevertheless, other potentially important variables (e.g., depression, social support, self-efficacy) were omitted from this study and could be explored in future research.
Despite these limitations, the findings from this study suggest that important sex differences exist in the experience of pain in persons with limb loss. These results may have implications for clinical practice and are also suggestive of future research directions in this population.