Other Variables
We created a single variable called level/laterality which categorized ULA as unilateral or bilateral. We further categorized respondents with unilateral amputation by their amputation level. We categorized respondents as transradial for wrist joint or below the elbow amputations; transhumeral for at or above the elbow amputations; and shoulder for shoulder joint or forequarter amputations. Participants indicated the amputation etiology using 7 yes/no variables: combat injury, accident, burn, cancer, diabetes mellitus, and infection. Participants could select ≥ 1 etiology.
Primary prosthesis type was categorized as body powered, myoelectric/hybrid, cosmetic, other/unknown, or nonuser. The service era was classified based on amputation date as Before Vietnam, Vietnam War, After Vietnam to Gulf War, After Gulf War to September 10, 2001, and September 11, 2001 to present. For race, individuals with > 1 race were classified as other. We classified participants by region, using the station identification of the most recent VA medical center that they had visited between January 1, 2010 and December 30, 2015.
The survey also employed 2 measures of satisfaction with the prosthesis, the Trinity Amputation and Prosthetic Experience Scale (TAPES) satisfaction scale and the OPUS Client Satisfaction with Devices (CSD). TAPES consists of 10 items addressing color, shape, noise, appearance, weight, usefulness, reliability, fit, comfort and overall satisfaction.11 Items are rated on a 5-point Likert scale from very dissatisfied (1) to very satisfied (5). An 8-item version of the CSD scale was created for this study, after conducting a Rasch analysis (using Winsteps version 4.4.2) of the original 11-item CSD. The 8 items assess satisfaction with prosthesis fit, weight, comfort, donning ease, appearance, durability, skin contact, and pain. Items are rated on a 4-point scale from strongly agree (1) to strongly disagree (4); higher CSD scores indicate less satisfaction with devices. Psychometric analysis of the revised CSD score was reported in a prior publication.12 We also reported on the CSS using the original 10-item measure.
Data Analyses
We described characteristics of respondents at baseline and follow-up. We used baseline data to calculate CSS scores and described scores for all participants, for subgroups of unilateral and bilateral amputees, and for unilateral amputees stratified by amputation level. Wilcoxon rank sum tests were used to compare the CSS item and total scores of 461 prosthesis users with unilateral amputation and 29 with bilateral amputation. To identify factors that we hypothesized might be associated with CSS scores at baseline, we developed separate bivariate linear regression models. We added those factors that were associated with CSS scores at P ≤ .1 in bivariate analyses to a multivariable linear regression model of factors associated with CSS score. The P ≤ .1 threshold was used to ensure that relevant confounders were controlled for in regression models. We excluded 309 participants with no reported prosthesis use (who were not asked to complete the CSS), 20 participants with other/unknown prosthesis types, and 106 with missing data on amputation care in the prior year or on satisfaction metrics. We used baseline data for this analysis to maximize the sample size.
We compared CSS scores for those who reported receiving care within or outside of the VA or DoD in the prior year, using Wilcoxon Mann-Whitney rank tests. We also compared scores of individual quality of care items for these groups using Fisher exact tests. We chose to examine individual items rather than the full Index because several items specified care receipt within the VA and thus would be inappropriate to utilize in comparisons by site location; however, we described responses to all items. In these analyses, we excluded 2 respondents who had conflicting information regarding location of care. We used follow-up data for this analysis because it allowed us to identify location of care received in the prior year.
We also described the CSS scores, the 7-item Quality of Care Index and responses to other items related to quality of care at baseline and follow-up. To examine whether satisfaction with prosthetic care or aspects of care quality had changed over time, we compared baseline and follow-up CSS and quality of care scores for respondents who had measures at both times using Wilcoxon signed ranks tests. Individual items were compared using McNemar tests.
Results
Respondents were 97.4% male and included 776 unilateral amputees and 32 bilateral amputees with a mean (SD) age of 63.3 (14.1) years (Table 1). Respondents had lost their limbs a mean (SD) 31.4 (14.1) years prior, and half were transradial, 34.2% transhumeral, and 11.6% shoulder amputation. At baseline 185 (22.9%) participants received amputation-related care in the prior year and 118 (20.2%) participants received amputation-related care within 1 year of follow-up. Of respondents, 113 (19.3%) stated that their care was between baseline and follow-up and 89 (78.8%) of these received care at either the VA, the DoD or both; just 16 (14.2%) received care elsewhere.
Mean (SD) CSS scores were highest (lower satisfaction) for those with amputation at the shoulder and lowest for those with transhumeral amputation: 42.2 (20.0) vs 33.4 (20.8). Persons with bilateral amputation were less satisfied in almost every category when compared with those with unilateral amputation, although the total CSS score was not substantially different. Wilcoxon rank sum analyses revealed statistically significant differences in wait time satisfaction: bilateral amputees were less satisfied than unilateral amputees. Factors associated with overall CSS score in bivariate analyses were CSD score, TAPES score, amputation care receipt, prosthesis type, race, and region of care (eAppendix 2, available at doi:10.12788/fp.0096).
In the multivariate regression model of baseline CSS scores, only 2 variables were independently associated with CSS scores: CSD score and recent amputation care (Table 3). For each 1-point increase in CSD score there was a 0.7 point increase in CSS score. Those with amputation care in the prior year had higher satisfaction when compared with those who had not received care (P = .003).
