Validity and reliability of the German version of the shortened thyroid-specific quality of life questionnaire (ThyPRO-39de)

Abstract

Objectives: Validation of a German version of the ThyPRO-39 questionnaire for quality of life (QoL) in patients with benign thyroid diseases. Design: Internal consistency, retest-reliability and validity were to be assessed in a test-retest study. Methods: The ThyPRO-39 was translated based on standard methodology. A sample of 98 patients with benign thyroid diseases was tested with the ThyPRO-39de and the generic EuroQol 5D-5L. 44 patients with stable symptoms after 2 weeks formed the repeated-measures sample. Cronbach’s alpha was calculated for the ThyPRO-39de composite score and for each disease specific scale. Intraclass correlations between the original and the repeated measures sample were calculated for each scale as well as Pearson correlations between various ThyPRO scales and the EuroQol. T-Tests were used to test for differences in the goiter and hyperthyroid symptom scales between relevant patient groups and other patients. Results: Internal consistency was between satisfactory and good, except for two scales (Tiredness and Cosmetic complaints/appearance). The test-retest correlation was between 0.62 and 0.8 for most scales, but below 0.5 for two scales (Tiredness and Impaired social life). There were significant correlations between the EuroQol index score and most aspects of the ThyPRO-39de. Only hyperthyroid symptoms scale was specific for the relevant patient group (Graves’ disease). Conclusion: The ThyPRO-39de may be recommended for use in clinical and research settings, especially with regards to the composite score. However, the underlying thyroid disease should always be kept in mind when interpreting the test results. A larger sample would be needed to implement further improvements.

Thyroid disease‐specific quality of life questionnaires ‐ A systematic review

“…Each scale can be evaluated individually, but there is also an additional score that combines seven scales. The short version of the ThyPRO can assess QoL in many different benign thyroid diseases, and in many different languages, for instance, German, Romanian, Greek or Spanish 22,23,26,28 …”

“…The Thy‐R‐HRQoL and the ThyPRO‐39 were developed after the publication by Wong et al 13 Thus, Wong's recommendation for the use of the ThyPRO to assess QoL in benign thyroid disease is also confirmed by this review. However, it should be noted that a validated German version of the ThyPRO‐39 questionnaire is now available, which can be used for the research on benign thyroid diseases 28 …”

“…However, it should be noted that a validated German version of the ThyPRO-39 questionnaire is now available, which can be used for the research on benign thyroid diseases. 28 For malignant thyroid diseases, six Qol questionnaires were identified. Three of the questionnaires have been developed as specific supplements to the valid, general EORTC questionnaire.…”

The Influence of Prophylactic Calcium and Magnesium Supplementation on Postoperative Quality of Life and Hypocalcemia After Total Thyroidectomy: Study Protocol for a Randomized Controlled Trial

“…We aim for a patient population of 80 male and female adults. This is based on a sample size calculation using data from our own validation study of the ThyPRO-39de ( 15 ). For sample size calculation the free software G * Power (Version 3.1.9.4) was used.…”

“…The effect size was calculated based on a mean of 30 points and a standard deviation of 19.6 for the ThyPRO-39 composite score for the control group [according to ( 15 )]. We assumed a mean decrease of about 10 points, which reflects a clinically relevant change, and no change in standard deviation for the intervention group.…”