German validation of the quality of life profile for spinal disorders (QLPSD).

BACKGROUND: The Quality of Life Profile for Spine Deformities (QLPSD) is a self-reporting questionnaire designed for studying patients with spinal deformities.

PURPOSE: The aim of the present study was to systematically translate the QLPSD into German (G-QLPSD) and to test its reliability and validity. Special emphasis was intended to be given to patients with different Cobb angles and ages.

METHODS: The QLPSD was systematically translated into German and was responded to in a web-based online survey by patients with idiopathic scoliosis and by healthy control individuals to carry out a matched-pair analysis. Participants aged 14 years and older were included. All participants answered a battery of validated questionnaires (SRS 22-r, PHQ-9, PANAS, FKS, WHO-5, BFI-S, PTQ). Reliability testing included Cronbach's alpha and test-retest reliability (retest 8 weeks after initial testing). Factorial, convergent, divergent, concurrent, and discriminant validity were calculated.

RESULTS: A total of 255 scoliosis patients (age 30.0 ± 16.7 years, Cobb angle 43.5° ± 20.9°) and 189 matched healthy control individuals were finally included. Cronbach's alpha for the G-QLPSD total score was 0.93 and the test-retest reliability was 0.84. The G-QLPSD total score correlated with the SRS 22-r total score (r = -0.86). All concurrently applied scores showed strong correlations with the G-QLPSD (e.g., depression score PHQ-9: r = 0.70). The matched-pair analysis of 189 pairs showed strong discriminant validity (Cohen's d = 0.78). Patients with more severe Cobb angles (≥40°) and those ≥18 years of age had significantly poorer results than patients with minor curves and younger patients.

CONCLUSION: The G-QLPSD proved to be a highly reliable and valid instrument that can be recommended for clinical use in scoliosis patients.