PROMIS instruments

PROMIS pain intensity was assessed on a modified numerical rating scale.21 Respondents were asked to rate their average pain intensity over the previous 7 days on a scale of 0–10. NIH PROMIS item banks22 for pain behavior, pain interference, physical function, sleep disturbance, sleep-related impairment, anger, depression, anxiety, and fatigue were administered using the CHOIR-Computerized Adaptive Testing algorithm. Detailed description of PROMIS item banks are available online (http://www.nihpromis.org/measures/domainframework1). PROMIS instruments utilize item response theory yielding standardized T-scores (mean =50, standard deviation [SD] =10)23; these scores are normed on a large sample of the US population.22 The pain behavior item bank measures an array of self-reported pain behaviors including distorted ambulation, facial/audible expressions, help-seeking behavior, reclining, minimizing movement, isolating oneself, increased body tension, avoiding physical contact with others, and massaging a painful area.24 Higher T-scores represent increased pain behaviors. The pain interference item bank measures the negative effect of pain on physical, mental, and social functioning in a range comparable to the majority of people who have pain.23 Higher T-scores represent increased pain interference with functioning. The physical function item bank measures self-reported functioning of extremities (dexterity and walking), axial regions (neck and back), and activities of daily living.25 Higher T-scores represent increased physical functioning. Thus, a score of 60 represents higher than average physical functioning. The sleep disturbance item bank measures perceived sleep quality, depth, and restoration.26 Higher T-scores represent increased sleep disturbance. The sleep-related impairment item bank measures self-reported alertness, sleepiness, and fatigue during waking hours, and the perceived functional impairments during wakefulness that are attributed to sleep problems or impaired alertness.26 Higher T-scores represent increased sleep-related impairment. The PROMIS item banks for anger measure angry mood (irritability and frustration), negative social cognitions, and efforts to control anger.27 The item bank for depression measures negative mood, negative views of self (worthlessness and self-criticism), social cognition (loneliness), and decreased positive affect and engagement (loss of interest, meaning, and purpose).27 The item bank for anxiety measures self-reported fear, anxious misery (worry and dread), hyperarousal, and somatic symptoms of arousal (racing heart and dizziness).27 The item bank for fatigue measures the frequency, duration, and intensity of fatigue in addition to its impact on physical, mental, and social functioning.28