Examining patient reported outcome measures for phantom limb pain: Measurement use in a sample of Veterans with amputation
Abstract: Purpose: Phantom limb pain (PLP) is treated with medications and non-drug treatments. Best clinical practices for measuring treatment outcomes have not been defined. The objective of this study was to evaluate the internal consistency of patient-reported outcomes measures (PROMs) in a sample of Veterans with lower limb amputation. Materials and methods: The Veteran phone survey included administering PROMs [1) PLP numeric rating scale (NRS), 2) general pain NRS, 3) Pain, Enjoyment, and General Activity (PEG) scale, 4) Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference Short Form 6b Replacement, 5) PROMIS Short Form Depression 4a and 6) PROMIS Short Form Anxiety 4a]. Results: Fifty Veterans (48 male, 2 female; average age: 66 years) completed PROMs. In our sample, 40 Veterans (80%) experienced PLP with an average PLP NRS of 5 (±3.4). Internal consistency of each measure was good to excellent based on Cronbach's alpha co-efficient of >0.80. Correlations were moderate between PLP NRS and all other measures (≤0.32). Although many Veterans expressed bothersome PLP, the scores reflecting pain interference and impact on function were lower than pain intensity. Consistent use of outcome measures is needed to determine the effect of interventions for amputation-related pain. Implications for rehabilitation: The majority of Veterans reported phantom limb pain and residual limb pain, though the frequency and duration of the pain conditions varied. Clinicians should use caution when using only the numeric rating scale to assess pain, as it may not give enough information to fully evaluate the pain experience. It is recommended that clinicians evaluate phantom limb pain separate from general pain to best serve patients’ needs. — eng