Effects of a Mindfulness-Based Intervention on Pain Severity, Pain Catastrophizing, Quality of Life, and Trait Mindfulness in Patients Undergoing Hemodialysis in Saudi Arabia

Pain Catastrophizing Scale (PCS)

Time Frame: From enrollment to the end of intervention at 5 weeks

Pain catastrophizing was measured using the 13-item Pain Catastrophizing Scale (PCS; Sullivan et al., 1995), administered in its Arabic-validated form (Terkawi et al., 2017). Each item is rated on a 5-point scale (0 = not at all to 4 = all the time) and summed to produce a total score ranging from 0 to 52, together with three subscale scores reflecting rumination, magnification, and helplessness. Higher scores indicate a greater tendency to catastrophize about pain-that is, more rumination, exaggerated appraisal of pain-related threat, and feelings of helplessness-while lower scores indicate a more adaptive, less distressed cognitive response to pain; a total score of 30 or above is commonly used in the pain literature as an indicator of clinically significant catastrophizing. The original PCS demonstrated strong internal consistency (α = .87) and good construct and criterion validity against measures of pain-related distress and disability (Sullivan et al., 1995)

Numeric Rating Scale (NRS)

Time Frame: From enrollment to the end of intervention at 5 weeks

Pain severity was measured using the Numeric Rating Scale (NRS), an 11-point self-report scale on which participants indicate the number, from 0 to 10, that best reflects their pain intensity at the time of assessment (Jensen et al., 1986; Scott \& Huskisson, 1976). A score of 0 represents "no pain" and a score of 10 represents "the worst pain imaginable"; scores are conventionally grouped into mild (1-3), moderate (4-6), and severe (7-10) pain. The NRS has demonstrated strong concurrent validity with the Visual Analogue Scale and good test-retest reliability across chronic and acute pain populations, and its simple response format makes it well suited to patients with fatigue or reduced dexterity during dialysis (Jensen et al., 1986).

Kidney Disease Quality of Life- Short Form

Time Frame: From enrollment to the end of intervention at 5 weeks

Quality of life was measured using the Kidney Disease Quality of Life Short Form (KDQOL-36), a 36-item, kidney-disease-specific instrument that combines the generic SF-12 physical and mental health composite scores with three kidney-specific subscales: symptoms/problems of kidney disease, effects of kidney disease on daily life, and burden of kidney disease. Each subscale and composite is transformed to a 0-100 metric, with higher scores indicating better perceived quality of life and a lower symptom or disease burden, and lower scores indicating poorer functioning and greater burden. The instrument has well-established reliability and validity in hemodialysis populations internationally, with subscale Cronbach's alpha values generally exceeding .70, and the Arabic version used in this study has demonstrated comparable internal consistency (α = .72-.92) and construct validity in Arabic-speaking dialysis samples (Elamin et al., 2019; Alhawatmeh et al., 2022).

Mindful Attention Awareness Scale

Time Frame: From enrollment to the end of intervention at 5 weeks

Trait, or dispositional, mindfulness was measured using the 15-item Mindful Attention Awareness Scale (Brown \& Ryan, 2003), which asks respondents to rate the frequency of everyday experiences of inattention and reduced present-moment awareness on a 6-point scale (1 = almost always to 6 = almost never). Scores are summed across the 15 items, yielding a total ranging from 15 to 90, with higher scores indicating a greater disposition toward sustained, present-moment attention and awareness in daily life, and lower scores indicating more frequent mind-wandering, automatic behavior, and inattentiveness. The original MAAS demonstrated strong internal consistency (α = .82) and good convergent and discriminant validity against measures of well-being and emotional distress (Brown \& Ryan, 2003), and the Arabic version used with Arabic samples, including dialysis populations, has shown similarly acceptable to strong reliability and validity (Alhawatmeh et al., 2022).