Development and psychometric assessment of the physical symptom distress scale

While the importance of subjective symptom distress for clinical evaluation of end-stage renal disease (ESRD) is generally acknowledged, an adequate method to classify and quantify this distress is currently unavailable. The purpose of this study was to develop the Physical Symptom Distress Scale (PSDS) to assess patients' physical symptom distress accompanying ESRD. The sample consisted of 160 ESRD patients from three dialysis centers of hospitals in Taipei, Taiwan. Internal consistency reliability of the instrument was found to be good: alpha coefficient = 0.87 for the entire scale, and alpha coefficients = 0.79 for each subscale, respectively. Test-retest correlation of 0.82 with a 2-week interval supported stability reliability. Factor analyses indicated and confirmed "Fluid and electrolyte imbalance" and "Disturbance in neuromuscular function" domains. Support for concurrent validity was provided by correlation (r = -0.46) between the entire scale and the Karnofsky Performance Scale (KPS). For Factor I the correlation was -0.51, for Factor II the correlation was -0.33. The predictive validity of the PSDS was supported through multiple regression. These findings suggest that the PSDS is a reliable and valid measure of symptom distress for ESRD patients treated with hemodialysis.