Table 1.

Patient-reported outcome measures.

Outcome							Description		Psychometrics
Pain
		PEGa				A 3-item instrument that evaluates pain intensity and its impact on enjoyment and general activity. Each item is scored from 0 to 10, and the 3 scores are averaged to yield a total PEG score, with higher values indicating greater pain and interference [26].		Internal consistency: Cronbach α=0.73 Validity: r=0.60-0.89 (in chronic musculoskeletal pain populations)
	PROMISb-Pain Interference Short Form				Assesses pain interference, which quantifies the self-reported impact of pain on social, cognitive, emotional, physical, and recreational domains. This instrument yields raw scores from 6 to 30, based on 6 items scored from 1 (“not at all”) to 5 (“very much”). Scores are converted to T-scores (mean 50, SD 10; range ~30 to over 80) standardized to the US general population. T-scores below 55 are within normal limits, 55-60 suggest mild, 60-70 moderate interference, and scores >70 reflect severe interference [27-29].				Internal consistency: Cronbach α=0.96-0.99 Test-retest reliability: ICCc=0.85 Convergent validity with the Brief Pain Inventory: r=0.80-0.85
Physical function
	PROMISb-Physical Function Short Form 6b					Assesses the broader influence of pain on life domains, with raw scores ranging from 6 to 30; each item is scored from 1 (“unable to do”) to 5 (“without any difficulty”). Converted T-scores (mean 50, SD 10) range approximately from 20 to >80. T-scores >45 are within normal limits, scores from 40 to 45 suggest mild limitation, scores from 30 to 40 indicate moderate limitation, and scores <30 reflect severe limitation [29-31].		Internal consistency: Cronbach α=0.96 for person and 0.99 for item Construct validity: r=0.657 (in patients undergoing foot and ankle surgery)
	FAAMd				Provides targeted assessment of foot and ankle function across two subscales: (1) activities of daily living (ADL), which includes 21 items scored from 0 (“unable to do”) to 4 (“no difficulty”), with a total score range of 0-84; and (2) sports, which includes 8 items with a total score range of 0-32. Scores are converted to percentages, with higher percentages reflecting better function [32].				Test-retest reliability: ICC=0.89 for the ADL; ICC=0.87 for the Sports. Correlations with the SF-36 physical function subscale: r=0.84-0.78 and physical component summary score: r=0.78-0.80
	VISA-A Sedentarye			Evaluates the severity of Achilles tendinopathy in sedentary individuals. It consists of 8 variably scored items addressing symptoms and activity impact, with a total score ranging from 0 to 100. A score of 100 indicates full function without symptoms, whereas scores <70 suggest notable impairment [33].					Test–retest reliability: ICC=0.991 for symptom and ICC=0.999 for activity Internal consistency: Cronbach α=0.72 Construct validity: r=0.42 for symptoms; r=0.40 for activity
Psychological factors
	PCS-6f		A short form of the Pain Catastrophizing Scale that measures catastrophic thinking about pain. It consists of 6 items across 3 subscales—2 items each for “rumination,” “helplessness,” and “magnification”—each scored from 0 to 4, yielding a total score of 0-24, with higher scores indicating greater catastrophic thinking [34,35].					Internal consistency: Cronbach α=0.88 Correlation with the full 13-item PCS: r=0.94 in individuals with chronic pain conditions
	TSK-11g					Measures fear of movement using 11 items from 1 (“strongly disagree”) to 4 (“strongly agree”), yielding a total score of 11-44. Scores <22 indicate minimal fear, 23-28 low fear, 29-35 moderate fear, and ≥36 high fear [36,37].		Convergent validity: association with pain catastrophizing, severity of expected pain with movement, and willingness to complete tendon loading exercises in individuals with Achilles tendinopathy Test-retest reliability: ICC=0.81 (in individuals with back pain)
	PHQ-2h		Screens for depression over the past 2 weeks using 2 items scored from 0 (“not at all”) to 3 (“nearly every day”), yielding a total range of 0-6. Scores of 0-2 suggest minimal or no depression, while scores ≥3 indicate possible depression requiring further evaluation [36].					Sensitivity: 83% Specificity: 92%
	PROMISb Sleep Disturbance					Evaluates sleep quality and disturbances across 8 items, each scored from 1 (“not at all”) to 5 (“very much”), yielding raw scores of 8-40. Scores are converted to T-scores (mean 50, SD 10), ranging approximately from 20 to >80. T-scores of 55-60 indicate mild sleep disturbance, 60-70 suggest moderate disturbance, and >70 reflect severe sleep disturbance [37,38].		Internal consistency: Cronbach α=0.96 Convergent validity with the Pittsburgh Sleep Quality Index: r=0.85 Test-retest reliability: ICC=0.62-0.71 (in fibromyalgia populations)
	PROMISb Self-Efficacy for Managing Symptoms 8a			Assess the subject’s level of confidence in managing their symptoms in different settings (home, public place, and an unfamiliar place) and in keeping their symptoms from interfering with work, sleep, relationships, or recreational activities. Each item scored from 1 (“not at all confident”) to 5 (“very confident”), yielding raw scores from 8 to 40. Converted T-scores below 30 suggest very low, 30-40 low, 40-60 average, 60-70 high, and 70-80 reflect very high self-efficacy [39].					Internal consistency: Cronbach α=0.92 Correlations with Chronic Pain Self-Efficacy Scale: r=0.74 (in patients with chronic conditions)
	GAD-2i			Screens for generalized anxiety disorder by asking about the frequency of feeling nervous and unable to control worrying over the past 2 weeks. It uses 2 items, each scored from 0 (“not at all”) to 3 (“nearly every day”), totaling 0 to 6. Scores of 0 to 2 indicate minimal or no anxiety, while scores of 3 or higher suggest possible anxiety requiring further assessment [40].					Sensitivity: 76% Specificity: 81% Internal consistency: Cronbach α=0.89
Comorbidities
	TAPS-1j			Screens for substance use in the past 12 months. Scores range from 0 to 4 (0=“never” and 4=“daily or almost daily”) for each substance category, with higher scores indicating more frequent use [41].					Sensitivity: 81%-96% Specificity: 78%-91%
	CCIk					Predicts 10-year mortality for patients with multiple comorbidities based on 19 weighted conditions, scored from 1 to 6 points, with a total range of 0 to >37. Higher scores correspond to a greater comorbidity burden [42-44].		Test-retest reliability: ICC=0.94 (for self-report data compared to chart reviews) Inter-rater reliability: ICC=0.80
	WPIl					Assesses pain distribution across 19 body areas, assigning a score of 0 if there is no pain and 1 if pain is present in each area. A total score of 7 or more typically indicates widespread pain. The SSSm scale evaluates symptom severity in 2 components: the first assesses fatigue, unrefreshing sleep, and cognitive difficulties, while the second derives a general symptom severity score based on the number of symptoms reported from a list of 41 symptoms. Patients receive a score of 0 for no symptoms, 1 for 1-10 symptoms, 2 for 11-24 symptoms, and 3 for 25 or more symptoms. The total SSS score ranges from 0 to 12, calculated by summing the scores from the first component (range 0-9) and the second (range 0-3) [45].		Internal consistency: Cronbach α=0.34 for the WPI, 0.83 for the SS, and 0.82 for the combined use of both tools. Sensitivity: 100% and Specificity: 81% for WPI Sensitivity: 89.2% and Specificity: 83.8% for SSS

^aPEG: Pain, Enjoyment, General Activity.

^bPROMIS: Patient-Reported Outcomes Measurement Information System.

^cICC: intraclass correlation coefficient.

^dFAAM: Foot and Ankle Ability Measure.

^eVISA-A Sedentary: Victorian Institute of Sport Assessment–Achilles (sedentary version).

^fPCS-6: Pain Catastrophizing Scale–6.

^gTSK-11: Tampa Scale for Kinesiophobia–11.

^hPHQ-2: Patient Health Questionnaire–2.

ⁱGAD-2: Generalized Anxiety Disorder–2.

^jTAPS-1: Tobacco, Alcohol, Prescription medication, and other Substance use.

^kCCI: Charlson Comorbidity Index.

^lWPI: Widespread Pain Index.

^mSSS: Symptoms Severity Scale.