Creating Quality Time: QOL Following Dysvascular Amputation

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By Phil Stevens, MEd, CPO, FAAOP

In a previous article, "Health-related Quality of Life: A Developing Standard in Healthcare"(The O&P EDGE, February 2017), I quoted the following from the U.S. Department of Health and Human Services' Healthy People 2020  literature:

 

Increasing life expectancy has also highlighted the need for other measures of health, especially those that capture the quality of the years lived.1

 

That article, which largely focused on Duchenne muscular dystrophy, concluded with mention of a study of individuals who had undergone lower-limb amputation and the progressive improvements in quality of life (QOL) that they reported as time passed from the original amputations.2

 

However, that study told only a small portion of the story. Lower-limb amputation is a devastating event, affecting individuals who often have limited resources to cope with the loss. In addition to the obvious physical compromise, amputation brings associated concerns of pain, restructured mobility, compromised balance, self-imposed activity limitations, and reduced societal participation, all of which can affect an individual's QOL. Further, these burdens are often compounded among individuals with dysvascular disease and associated comorbidities that undermined QOL prior to the amputation.

 

This article reviews recent literature pertaining to QOL among people who have experienced a lower-limb amputation, with an emphasis on those with dysvascular amputation etiologies.

 

Defining the Health Profile

Before describing the factors and domains that appear to influence QOL in this population, some narrative describing their overall health profile is indicated. This discussion is enabled by a recent study utilizing an instrument from the federally funded Patient-Reported Outcomes Measurement Information System (PROMIS).3 PROMIS instruments are patient-reported outcome measures that have been indexed to samples representative of the general U.S. population regarding gender, age, race, ethnicity, and education. PROMIS scores are based on the T-score metric, in which a score of 50 represents the mean of the general U.S. population, and standard deviations are found at ten points above or below that mean. Thus, these instruments allow intuitive indexing of a target population against the general U.S. population.

 

Recently, the PROMIS-29 was administered among a sample of over 1,000 people with amputations to assess their physical, mental, and social health against those of the general U.S. population.3 Of the many constructs included in the measure, individuals with amputations fared noticeably worse in the domains of physical function, pain interference, and satisfaction with social roles.

 

The most striking deficit was observed in self-reported physical function. Among the aggregate population of people with amputations, the mean physical function T-score was 41.9, nearly a full standard deviation below the mean of the U.S. population. However, this number was heavily influenced by amputation etiology. Among those with traumatic amputations, the average T-score for physical function was a more moderate 44.5. Among those with dysvascular amputations, the average score drops outside of the first standard deviation to 38.5.3

 

The significance of that number requires a quick reminder about what a standard deviation represents. Assuming a normal distribution, the standard deviations above and below the mean each represent 34 percent of the population, leaving only 16 percent of the population represented more than one standard deviation below the mean. To have the mean score for an entire subpopulation within this range suggests that their physical function is, on average, more compromised than 84 percent of the general U.S. population.

 

Though comparatively less pronounced, the discrepancy in satisfaction with social roles between the general U.S. population and those with lower-limb amputations was also notable. For the entire population of people with lower-limb amputations, the average T-score of 48 was just below general population averages. However, when broken down by amputation etiology, two situations emerge. For those with amputations of traumatic etiology, satisfaction with social roles was virtually unencumbered, with an average T-score of 49.9. However, for those with amputations of vascular etiology, the average T-score in this domain fell to 45.6, or nearly half of a standard deviation.

 

Pain interference was the final domain where scores in the population of individuals with amputations differed markedly from the general U.S. population, with an average T-score of 54.8. This implies that people with limb loss have pain that interferes with their participation in life activities more than the general population. The experience of pain was fairly uniform irrespective of amputation etiology, with people with traumatic amputations and those with vascular amputations reporting average T-scores of 54.1 and 55.7 respectively.

 

Given the observed discrepancies in physical function, satisfaction with social roles, and pain interference between the general population and the amputee population, especially when amputation is due to vascular compromise, it is reasonable to expect that these areas may undermine the QOL of those with lower-limb amputations.

 

Prevalent Influencing Factors

A recently published systematic review of the various factors that influence QOL after amputation due to vascular disease begins to confirm this supposition.4 The review paints a rather bleak picture of potential QOL among this population, explaining that most such individuals are older adults prone to comorbid health conditions with a life expectancy of only two to five years. Many prosthetists, biased by the number of these individuals presenting in the clinic with a prescription for a prosthesis, may be surprised to learn that only 40 percent of older adults who undergo lower-limb amputations receive a prosthetic referral.

 

Drawing from 12 publications that met the inclusion criteria for the systematic review, Davie-Smith et al. report that "walking with a prosthesis was the most notable factor that influenced QOL and was reported by all 12 studies."4 A sample of their summarized "Main Findings" underscores this relationship.

 

• From Buijck et al., "Low QOL was correlated positively to poor functional ambulation score."
• From Fortington et al., "The ability to walk was related to improved social function and higher QOL."
• From Norvell et al., "If mobility success was achieved, then participants were more likely to have improved satisfaction with life."
• From Abdelgadir et al., "Reduced mobility in LLAs [lower-limb amputees] was highly correlated to the role physical aspect of QOL scores."
• From Cox et al., "Positive correlation was found between functional independence and QOL in all participants."
• From Harness and Pinzur, "Satisfaction correlated with…the ability to ambulate."
• From Pell et al., "QOL is directly linked to mobility."
• From Remes et al., "Reduced mobility was an independent factor in poor QOL."

Even when other variables such as social isolation or emotional distress are controlled for, when comparing QOL to age- and gender-matched controls, the ability to walk has a significant beneficial effect.4 Indeed, even small amounts of walking appear to benefit QOL. Notably, it was also suggested that the association between walking and QOL was because walking enables social interaction more than it influences improved physical fitness.4

 

Other factors identified that influence QOL were amputation level, gender, age, diabetes, and family support. Directionality was largely predictable. Transtibial amputation was associated with higher QOL than transfemoral amputation, largely because of the differences in walking potential (receipt of a prosthesis occurs for 75 percent of those with transtibial amputation, compared to only 25 percent of those with transfemoral amputation). QOL is also reduced with age, perhaps reflective of the reduced ambulatory potential observed with increased age. Diabetes and other comorbid health conditions were associated with decreased QOL. Women report higher QOL after lower-limb amputation than men. Unlike ambulation status, these variables are not only less prevalent in the reviewed literature, they are largely unchangeable.

 

Further Correlating Mobility and Quality of Life

Recent efforts within Hanger Clinic's Department of Scientific Affairs have further defined the relationship between mobility and quality of life.5 Reviewing a convenience sample of 509 patients seen in patient care clinics, patients reported mobility was correlated with their reported QOL and general satisfaction. While individuals with vascular amputations, vascular disease, and diabetes did not exclusively comprise the cohort, those were the most frequently reported amputation etiologies, representing 202 of the respondents.5 Positive correlations were found between mobility and both QOL and satisfaction, with r-values approximating 0.50. Restated, patients who reported greater prosthetic mobility, tended to report higher QOL and satisfaction with life.5

 

Additional Determinants

A recent publication not considered in the cited systematic review further examined the determinants of QOL using focus group interviews. Conducted with 26 patients with lower-limb amputations due to dysvascular disease in four centers around the country, the findings supported some of the observations of the systematic review, while also introducing new considerations.6

 

Consistent with the systematic review, mobility was identified as the greatest QOL determinant, with 65 percent of the participants stating that mobility, or the lack thereof, had the greatest impact on QOL.6 As one subject stated, "You can't stop or start like you used to. People cut you off, bump into you, crowd you." Another added, "It is difficult. You have to really pay attention when going down a ramp or climbing stairs."6 Ultimately, mobility concerns included challenges with balance, difficulties in navigating environmental obstacles like ramps and stairs, and the frequency with which these limitations precluded engagement in social activities. Of note, the focus group participants unanimously agreed that a prosthesis either improves or would improve the QOL. Further, in addition to being the most prevalent consideration, mobility had indirect effects on the other prevalent themes identified by the groups.

 

Pain was the next domain that affected QOL, identified by 60 percent of the respondents.6 Many subjects commented that pain was a key consideration in their decision to proceed with amputation, with 85 percent agreeing that "intolerable ischemic rest pain is the most appropriate threshold for having their limb amputated."6 Many individuals were upset that pain persisted after their amputations as phantom limb pain. Yet there was unanimous consent that phantom limb pain was preferable to ischemic rest pain. Roughly half of the participants were taking chronic pain medications, either to mitigate phantom limb pain, or to manage the ongoing ischemic pain in the contralateral limb. Relating to mobility, in describing the relationship between pain and QOL, participants talked about how pain limited their daily activity and social interactions.

 

The third most commonly identified domain affecting QOL, identified by 55 percent of participants, was concern for the remaining limb.6 Those with unilateral amputations expressed concern over the prospect of a second amputation, as represented by the statements, "I couldn't handle losing the second leg," and "I don't want to go through it again."6 Among those with bilateral amputations, QOL had been further compromised. "I told my surgeon that if I wake up without the other leg, I don't want to wake up at all," and "When I lost the other leg, I became even more depressed [and] thought my life was over."4 Unfortunately, half of the participants with unilateral amputations stated that they were dealing with either tissue loss or ischemic rest pain in their remaining limb.6

 

The QOL domain identified by 54 percent of participants was depression, with apparent ties to compromised mobility.6 Specifically, participants described feeling alone and sad, "often spending days without leaving their home." Indeed, 40 percent of patients traced part of their depression to their lack of independence and social support, with direct limitations on QOL.6

 

Summary

Numerous variables have emerged that appear to strongly influence those individuals who have experienced an amputation due to dysvascular disease. Variables such as age, gender, amputation level, and comorbid health conditions can't be addressed during prosthetic rehabilitation, but fortunately, the most pronounced variables of mobility, pain, and social participation can be addressed. Pain, often reduced through the process of amputation, can be managed pharmaceutically when needed. Mobility can be enabled by an appropriate prosthesis with requisite training. Social participation appears to be largely influenced by mobility since patients who can get out of their homes generally prefer to do so.

 

An understanding of those variables that have the greatest detrimental impact to the quality of life of those individuals with vascular amputations allows clinicians to tailor their interventions toward those needs. Thus, enhancing mobility inside and outside of the home and mitigating the interference of pain should be at the forefront of clinical consideration, both for their immediate, inherent benefits and their cumulative benefits in the resultant quality of life.

 

Phil Stevens, MEd, CPO, FAAOP, is in clinical practice with Hanger Clinic, Salt Lake City. He can be contacted at philmstevens@hotmail.com.

References

1. U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. Healthy People 2020, Foundation Health Measure Report, Health-Related Quality of Life and Well-Being. www.healthypeople.gov/sites/default/files/HRQoLWBFullReport.pdf

2. Fortington, L. V., et al. 2013. Change in health-related quality of life in the first 18 months after lower limb amputation: A prospective, longitudinal study. Journal of Rehabilitation Medicine 45: 587-94.

3. Amtmann, D., S. J. Morgan, J. Kim, B. J. Hafner. 2015.Health-related profiles of people with lower limb loss. Archives of Physical Medicine and Rehabilitation 96:1474-83.

4. Davie-Smith, F., et al. 2017. Factors influencing quality of life following lower limb amputation for peripheral arterial occlusive disease: A systematic review of the literature. Prosthetics and Orthotics International 41(6): 537-47.

5. Wurdeman SR, Stevens PM and Campbell JH.  Mobility Analysis of Amputees (MAAT I): Quality of life and satisfaction are strongly related to mobility for patients with a lwer limb prosthesis.  Prosthetics & Orthotics International.  2017 Oct 1:0309364617736089.

     6. Suckow, B. D., et al. 2015. Domains that determine quality of life in vascular amputees. Annals of Vascular Surgery 29:722-30.