Establishing construct validity for the thyroid-specific patient reported outcome measure (ThyPRO): an initial examination

Measurement and Variation in Estimation of Quality of Life Effects of Patients Undergoing Treatment for Papillary Thyroid Carcinoma

BACKGROUND

Thyroid cancer incidence is increasing. The effect of diagnosis and treatment on health-related quality of life (HRQoL) is an essential variable in the absence of a change in life span for the majority of patients. HRQoL instruments, with data useful for between-disease comparisons, are being increasingly used for health policy and outcomes evaluation. Variation exits among the instruments based on the impact of a specific disease. We assessed which of four well-validated, preference-based surveys detect changes in health and clinical intervention in patients diagnosed with papillary thyroid cancer (PTC).

METHODS

Four commonly used HRQoL questionnaires (Short Form-12v2® [SF6D], EuroQol-5D [EQ5D], and Health Utilities Index Mark 2 and 3 [HUI2, HUI3]) were administered to patients with the diagnosis of PTC at three perioperative time points during the first year of treatment. Clinicopathological and treatment course data were assessed for HRQoL impact including complications from surgery, re-operation for persistence/early recurrence, and adjuvant radioactive iodine treatment. We compared standard metrics, including ceiling effect, intraclass correlation coefficient, effect sizes, and quality-adjusted life-years between the four instruments.

RESULTS

Of 117 patients, 27% had a preoperative diagnosis of anxiety or depression, 41% had regional lymph node metastases, three had distant metastases and 49% underwent adjuvant radioactive iodine treatment. The ceiling effect (i.e., proportion with a perfect score) was greatest with EQ5D and least with SF6D. Index scores ranged from 0.77 (SF6D) to 0.90 (EQ5D). All scores declined at two weeks postoperatively and returned to pretreatment levels at six months. The SF6D was the only instrument to exceed the conventional minimally important difference between all three time points. Quality-adjusted life-years were as follows: SF6D, 0.79; EQ5D, 0.90; HUI2, 0.88; and HUI3, 0.86.

CONCLUSIONS

Our results reflect the general good health of PTC patients. The effect on quality of life is primarily related to emotional and social impacts of treatment. The results support the measurement of a similar underlying construct, although variation in detecting changes in health exists between the instruments. Of the instruments assessed, the SF6D is the most responsive to treatment effects and should be utilized in future economic analyses in this patient population.

Quality-of-Life Impairments Persist Six Months After Treatment of Graves' Hyperthyroidism and Toxic Nodular Goiter: A Prospective Cohort Study

BACKGROUND

The treatment of hyperthyroidism is aimed at improving health-related quality of life (HRQoL) and reducing morbidity and mortality. However, few studies have used validated questionnaires to assess HRQoL prospectively in such patients. The purpose of this study was to assess the impact of hyperthyroidism and its treatment on HRQoL using validated disease-specific and generic questionnaires.

METHODS

This prospective cohort study enrolled 88 patients with Graves' hyperthyroidism and 68 with toxic nodular goiter from endocrine outpatient clinics at two Danish university hospitals. The patients were treated with antithyroid drugs, radioactive iodine, or surgery. Disease-specific and generic HRQoL were assessed using the thyroid-related patient-reported outcome (ThyPRO) and the Medical Outcomes Study 36-item Short Form (SF-36), respectively, evaluated at baseline and six-month follow-up. The scores were compared with those from two general population samples who completed ThyPRO (n = 739) and SF-36 (n = 6638).

RESULTS

Baseline scores for patients with Graves' hyperthyroidism and toxic nodular goiter were significantly worse than those for the general population scores on all comparable ThyPRO scales and all SF-36 scales and component summaries. ThyPRO scores improved significantly with treatment on all scales in Graves' hyperthyroidism and four scales in toxic nodular goiter, while SF-36 scores improved on five scales and both component summaries in Graves' hyperthyroidism and only one scale in toxic nodular goiter. In Graves' hyperthyroidism, large treatment effects were observed on three ThyPRO scales (Hyperthyroid Symptoms, Tiredness, Overall HRQoL) and moderate effects on three scales (Anxiety, Emotional Susceptibility, Impaired Daily Life), while moderate effects were seen in two ThyPRO scales in toxic nodular goiter (Anxiety, Overall HRQoL). However, significant disease-specific and generic HRQoL deficits persisted on multiple domains across both patient groups.

CONCLUSIONS

Graves' hyperthyroidism and toxic nodular goiter cause severe disease-specific and generic HRQoL impairments, and HRQoL deficits persist in both patient groups six months after treatment. These data have the potential to improve communication between physicians and patients by offering realistic estimates of expected HRQoL impairments and treatment effects. Future studies should identify risk factors for persistent HRQoL deficits, compare HRQoL effects of the various therapies, and thereby aid in determining the optimal treatment strategies.

Disease-Specific as Well as Generic Quality of Life Is Widely Impacted in Autoimmune Hypothyroidism and Improves during the First Six Months of Levothyroxine Therapy

BACKGROUND

Hypothyroidism is often diagnosed, and subsequently treated, due to health-related quality of life (HRQL) issues. However, HRQL following treatment has never previously been assessed in longitudinal descriptive studies using validated instruments.

OBJECTIVE

To investigate disease-specific (ThyPRO) and generic (SF-36) HRQL, following levothyroxine therapy in patients with hypothyroidism due to autoimmune thyroiditis.

METHODS

This prospective cohort study was set at endocrine outpatient clinics at two Danish university hospitals. Seventy-eight consecutive patients were enrolled and completed HRQL questionnaires before, six weeks, and six months after initiation of levothyroxine therapy. Normative ThyPRO (n = 739) and SF-36 (n = 6,638) data were available for comparison and changes in HRQL following treatment were estimated and quantified.

RESULTS

Prior to treatment, all ThyPRO scales were significantly impacted (p<0.0001), compared to the general population sample. The same was observed for seven of eight SF-36 scales, the exception being Bodily Pain. Tiredness (ThyPRO) and Vitality (SF-36) were the most markedly impacted scales. After six weeks of treatment, nine of thirteen ThyPRO scales had significantly improved. ThyPRO improvements were consistent at six months, where five of eight SF-36 scales had also significantly improved, but deficits persisted for a subset of both ThyPRO and SF-36 scales.

CONCLUSIONS

In this population of hypothyroid patients, HRQL was widely affected before treatment, with tiredness as the cardinal impairment according to both ThyPRO and SF-36. Many aspects of HRQL improved during the first six months of LT4 therapy, but full recovery was not obtained. Our results may help clinicians inform patients about expected clinical treatment effects.

A systematic review of quality of thyroid-specific health-related quality-of-life instruments recommends ThyPRO for patients with benign thyroid diseases

OBJECTIVES

To appraise the measurement properties of thyroid-specific health-related quality-of-life (HRQOL) instruments and to provide recommendations on the choice of HRQOL instruments.

STUDY DESIGN AND SETTING

Systematic review of English-language literature published between 1993 and 2015 identified psychometric studies involving patients with thyroid disease through a search of Pubmed, Web of Science, Embase, and OVID MEDLINE. HRQOL instruments were graded on methodological quality and overall levels of evidence using a COSMIN checklist.

RESULTS

After a review of 742 original studies, 23 studies reporting 14 standardized HRQOL instruments targeted for Graves' ophthalmopathy (n = 4), hypothyroidism (n = 3), thyroid cancer (n = 2), other thyroid disease (n = 3), and nonthyroid tumor sites (n = 2) were identified. Hypothesis testing was evaluated most frequently. The 84-item thyroid-specific patient-reported outcome measure (ThyPRO) and 16-item Graves' ophthalmopathy-specific Quality-of-Life (GO-QOL) instruments were the most extensively evaluated instrument. The highest number of positive ratings in overall level of psychometric evidence was found in ThyPRO, GO-QOL, and 11-item Thyroid Treatment Satisfaction Questionnaire (ThyTSQ) instruments.

CONCLUSION

The ThyPRO is recommended for the assessment of HRQOL in patients with benign thyroid diseases while measurement properties of GO-QOL and ThyTSQ are satisfactory in measuring HRQOL of patients with Graves' ophthalmopathy and hypothyroidism, respectively.

High Level of Agreement between Electronic and Paper Mode of Administration of a Thyroid-Specific Patient-Reported Outcome, ThyPRO

INTRODUCTION AND PURPOSE

Use of electronic questionnaires to collect health-related quality-of-life data has evolved as an alternative to paper questionnaires. For the electronic questionnaire to be used interchangeably with the validated paper questionnaire, measurement properties similar to the original must be demonstrated. The aim of the present study was to assess the equivalence between the paper version and the electronic version of the thyroid-related quality-of-life questionnaire ThyPRO.

METHODS

Patients with Graves' hyperthyroidism or autoimmune hypothyroidism in a clinically stable phase were included. The patients were recruited from two endocrine outpatient centers. All patients completed both versions in a randomized test-retest set-up. Scores were compared using intraclass correlation coefficients (ICCs), paired t tests and Bland-Altman plots. Limits of agreement were compared with data from a previous paper-paper test-retest study.

RESULTS

104 patients were included. ICCs were generally high for the 13 scales, ranging from 0.76 to 0.95. There was a small but significant difference in the scale score between paper and electronic administration for the Cosmetic complaints scale, but no differences were found for any other scale. Bland-Altman plots showed similar limits of agreement compared to the earlier test-retest study of the paper version of ThyPRO.

CONCLUSION

Based on our analyses using ICCs, paired t tests and Bland-Altman plots, we found adequate agreement between the paper and electronic questionnaires. The statistically significant difference in score found in the Cosmetic complaints scale is small and probably clinically insignificant.

Development of a Short Version of the Thyroid-Related Patient-Reported Outcome ThyPRO

BACKGROUND

Thyroid diseases affect quality of life (QoL). The Thyroid-Related Patient-Reported Outcome (ThyPRO) is an international comprehensive well-validated patient-reported outcome, measuring thyroid-related QoL. The current version is rather long--85 items. The purpose of the present study was to develop an abbreviated version of the ThyPRO, with conserved good measurement properties.

METHODS

A cross-sectional (N = 907) and a longitudinal sample (N = 435) of thyroid patients were analyzed. A graded item response theory (IRT) model was fitted to the cross-sectional data. Short-form scales with three items were aimed for, by selecting items with best fit according to the IRT model, avoiding cross-culturally noninvariant items. Seven scales measuring mental and social well-being and function as well as one overall QoL impact item were analyzed in a bifactor model, to develop a supplementary composite score. Short-form scales were linked to original scales with IRT-based summed-score-linking. Agreement between the short and long form was estimated by agreement plots, intraclass correlations, and mean score levels. Responsiveness was compared by relative validity indices, clinical validity by ability to detect clinically relevant differences, and test-retest reliability by intra-class correlation.

RESULTS

One four-item scale was not abbreviated and one two-item scale was omitted from the short-form. For the 11 scales undergoing abbreviation, 10 with three and one with four items were developed. A bifactor model with good overall fit was fitted to the composite score, including the single QoL item. Responsiveness and clinical validity of the short-form scales were preserved, as were test-retest reliability (0.75-0.89). Short- versus long-form intraclass correlations were high (0.89-0.98), and the mean scale levels were similar.

CONCLUSIONS

A 39-item version of the ThyPRO, with good measurement properties, was developed and is recommended for clinical use.

Quality of life in patients with benign nontoxic goiter: impact of disease and treatment response, and comparison with the general population

BACKGROUND

While health-related quality of life (HRQoL) issues often prompt treatment of benign nontoxic goiter (NTG), few clinical studies have systematically assessed HRQoL in patients with this condition. The purpose of the present study was to evaluate thyroid-related and generic HRQoL in patients with benign NTG, as compared to the general population, before and six months after treatment.

METHODS

Thyroid-related and generic HRQoL were assessed with Thyroid Patient-Reported Outcome (ThyPRO) and Medical Outcomes Study 36-item Short Form (SF-36), respectively. Baseline and six-month post-treatment HRQoL assessments were obtained from 111 patients with NTG who underwent radioiodine therapy (32%), hemithyroidectomy (53%), total thyroidectomy (12%), or cyst aspiration with ethanol sclerotherapy (4%). Euthyroid patients were enrolled at baseline, 80% of whom remained euthyroid six months post-treatment, with 20% experiencing subclinical thyroid dysfunction. Normative ThyPRO (n=739) and SF-36 (n=6638) data were collected from representative general population samples. Score differences between patients and the general population were analyzed with multivariate linear regression analysis, adjusting for age, sex, comorbidity, and educational status. Changes in scores between baseline and follow-up were analyzed with the paired t-test, and magnitudes of score changes were evaluated as effect sizes (mean difference/SDbaseline; 0.2-0.5 indicating small, 0.5-0.8 moderate, and >0.8 large effects).

RESULTS

Patients' baseline scores were significantly worse than those in the general population on 9 of the 13 ThyPRO scales. Six months after treatment, the patients' ThyPRO scores had improved on six scales, with large/moderate effects on the Goiter Symptoms and Anxiety scales. However, on eight scales, the post-treatment patient scores were still significantly worse than the general population scores. At baseline, patients had worse scores than the general population on four of the eight SF-36 scales and the SF-36 Mental Component Summary, none of which improved after treatment.

CONCLUSIONS

Compared with the general population, patients with NTG had greatest HRQoL impairment at baseline on the Goiter Symptoms and Anxiety scales, which also demonstrated the largest post-treatment improvements. However, both disease-specific and generic HRQoL deficits persisted six months after treatment. In order to improve individualized care, future studies should focus on identifying risk factors for persistent HRQoL deficits and compare HRQoL effects of the various goiter treatment modalities in relation to thyroid phenotype.

Thyroid-specific questions on work ability showed known-groups validity among Danes with thyroid diseases

Purpose

We aimed to identify the best approach to work ability assessment in patients with thyroid disease by evaluating the factor structure, measurement equivalence, known-groups validity, and predictive validity of a broad set of work ability items.

Methods

Based on the literature and interviews with thyroid patients, 24 work ability items were selected from previous questionnaires, revised, or developed anew. Items were tested among 632 patients with thyroid disease (non-toxic goiter, toxic nodular goiter, Graves’ disease (with or without orbitopathy), autoimmune hypothyroidism, and other thyroid diseases), 391 of which had participated in a study 5 years previously. Responses to select items were compared to general population data. We used confirmatory factor analyses for categorical data, logistic regression analyses and tests of differential item function, and head-to-head comparisons of relative validity in distinguishing known groups.

Results

Although all work ability items loaded on a common factor, the optimal factor solution included five factors: role physical, role emotional, thyroid-specific limitations, work limitations (without disease attribution), and work performance. The scale on thyroid-specific limitations showed the most power in distinguishing clinical groups and time since diagnosis. A global single item proved useful for comparisons with the general population, and a thyroid-specific item predicted labor market exclusion within the next 5 years (OR 5.0, 95 % CI 2.7–9.1).

Conclusions

Items on work limitations with attribution to thyroid disease were most effective in detecting impact on work ability and showed good predictive validity. Generic work ability items remain useful for general population comparisons.

Confirmatory factor analysis of the thyroid-related quality of life questionnaire ThyPRO

Background and aim

Thyroid diseases are prevalent and chronic. With treatment, quality of life is restored in most, but not all patients. Construct validity of the thyroid-related quality of life questionnaire, ThyPRO, has been established by multi-trait scaling, but not evaluated with more elaborate methods. The purpose of the present study was to evaluate dimensionality of the ThyPRO scales and to attempt to understand possible item misfit through structural equation modeling for categorical data.

Methods

The current 85-item version of ThyPRO consists of 13 scales, covering domains of physical (4 scales) and mental (2 scales) symptoms, function and well-being (3 scales) and participation/social function (4 scales). The data were collected from a cross-sectional sample of 907 thyroid patients. One-factor confirmatory models were fitted to each scale, and evaluated by model fit statistics (comparative fit index >0.95, root mean square error of approximation <0.08), magnitude of factor loadings, model residual correlations and modification indices (MI). Indications of multi-dimensionality were tested in bi-factor models. Possible item misfit was evaluated in a combined, investigational model.

Results

Each ThyPRO scale was adequately represented by a unidimensional model after minor revisions. Eleven items were identified in the unidimensional models as potentially misfitting and were investigated further by multidimensional modeling.

Conclusion

Elaborate psychometric modeling supported the construct validity of the ThyPRO. However, 11 potentially misfitting items and 18 items with local dependence to other items are candidates for removal in future item reduction processes.

Anxiety and depression are more prevalent in patients with graves' disease than in patients with nodular goitre

BACKGROUND AND OBJECTIVE

Graves' disease has been associated with an increased psychiatric morbidity. It is unclarified whether this relates to Graves' disease or chronic disease per se. The aim of our study was to estimate the prevalence of anxiety and depression symptoms in patients with Graves' disease compared to patients with another chronic thyroid disease, nodular goitre, and to investigate determinants of anxiety and depression in Graves' disease.

METHODS

157 cross-sectionally sampled patients with Graves' disease, 17 newly diagnosed, 140 treated, and 251 controls with nodular goitre completed the Hospital Anxiety and Depression Scale (HADS). The differences in the mean HADS scores between the groups were analysed using multiple linear regression, controlling for socio-demographic variables. HADS scores were also analysed dichotomized: a score >10 indicating probable 'anxiety'/probable 'depression'. Determinants of anxiety and depression symptoms in Graves' disease were examined using multiple linear regression.

RESULTS

In Graves' disease levels of anxiety (p = 0.008) and depression (p = 0.014) were significantly higher than in controls. The prevalence of depression was 10% in Graves' disease versus 4% in nodular goitre (p = 0.038), anxiety was 18 versus 13% (p = 0.131). Symptoms of anxiety (p = 0.04) and depression (p = 0.01) increased with comorbidity. Anxiety symptoms increased with duration of Graves' disease (p = 0.04). Neither thyroid function nor autoantibody levels were associated with anxiety and depression symptoms.

CONCLUSIONS

Anxiety and depression symptoms were more severe in Graves' disease than in nodular goitre. Symptoms were positively correlated to comorbidity and duration of Graves' disease but neither to thyroid function nor thyroid autoimmunity.

Assessing health-related quality of life in patients with benign non-toxic goitre

Health-related quality of life (HRQoL) assessments are increasingly used to evaluate treatment effects and to shape the delivery of value based care. Valid generic and disease specific tools are available for quantifying HRQoL in patients with non-toxic goitre. However, few studies have applied these validated instruments to assess HRQoL in patients with benign non-toxic goitre. Limited evidence suggests that patients with non-toxic goitre have HRQoL impairments in multiple HRQoL domains. While the HRQoL-impact of non-toxic goitre may be small relative to other severely disabling medical conditions, treatment is almost exclusively elected for HRQoL indications. Thus better quantification of HRQoL, particularly at better (or more favorable) levels where many patients score, is essential. Web and mobile technologies have eased the ability to deliver surveys to patients. Routine consideration of HRQoL provides the opportunity to monitor the impact of treatment on the outcomes most meaningful for patients and the opportunity to help shape the delivery of value based health care.

Quality of life (QoL) in patients with benign thyroid goiters (pre- and post-thyroidectomy): a prospective study

BACKGROUND

Preservation of quality of life (QoL) seems an important therapeutic goal in patients with benign thyroid diseases. The aim of the present study was to investigate the impact of thyroidectomy on QoL in patients with benign goiters and to assess the significance of various factors affecting the outcome.

METHODS

A prospective study consisting of 100 patients with benign goiters was conducted between November 2009 and March 2011. Patients completed a disease-specific ThyPRO questionnaire to assess QoL before and 6 months after thyroidectomy. Preoperative and postoperative scores were compared; and univariate and multivariate analyses were performed.

RESULTS

Mean age of the patients was 40.5 years (M:F = 1:4.3); 82 % of the patients had nodular goiters, and the remaining 18 % had diffuse disease. None of the patients had overt thyroid dysfunction at the time they completed the questionnaire. Operative treatment for 54 % of the patients involved total thyroidectomy, whereas 46 % underwent hemithyroidectomy. None of these patients developed any permanent morbidity following surgery. Mean scores of QoL in the 12 domains examined were low and improved significantly (p < 0.001) after surgery: symptoms, 19.4 versus 0.7; fatigue, 29.5 versus 1.5; vitality, 44.4 versus 3.0; memory and concentration, 25.7 versus 1.5; nervousness, 29.6 versus 1.8; psychological well-being, 33.9 versus 1.3; mood swings, 34.9 versus 0.8; relationship, 15.4 versus 1.4; daily activity, 18.7 versus 1.3; sex life, 20.9 versus 1.7; appearance, 14.7 versus 1.0; and overall, 27 versus 5.5. On univariate analysis, weight of goiter was found to be significantly associated with improvement in the scores of the memory and concentration domain (p = 0.03). On multivariate analysis, factors significantly associated with improvement in different domains were young age (nervousness, p = 0.009), female gender (fatigue, p = 0.02), and weight of goiter (symptoms, p = <0.001; vitality, p = <0.001; and memory and concentration, p = <0.001).

CONCLUSIONS

Patients with benign goiters experience significant improvement in QoL after thyroidectomy.

The chronic autoimmune thyroiditis quality of life selenium trial (CATALYST): study protocol for a randomized controlled trial

BACKGROUND

Patients with chronic autoimmune thyroiditis have impaired health-related quality of life. The thyroid gland has a high selenium concentration, and specific selenoprotein enzyme families are crucial to immune function, and catalyze thyroid hormone metabolism and redox processes in thyroid cells. Previous randomized controlled trials have found that selenium supplementation decreases thyroid-disease-specific antibody levels. We hypothesize that selenium might be beneficial in the treatment of chronic autoimmune thyroiditis.

METHODS/DESIGN

The CATALYST trial is an investigator-initiated randomized, blinded, multicentre clinical trial of selenium supplementation versus placebo in patients with chronic autoimmune thyroiditis.

INCLUSION CRITERIA

age ≥18 years; serum thyroid peroxidase antibody level ≥100 IU/ml within the previous 12 months; treatment with levothyroxine and written informed consent.

EXCLUSION CRITERIA

previous diagnosis of toxic nodular goitre, Graves' hyperthyroidism, postpartum thyroiditis, Graves' orbitopathy; previous antithyroid drug treatment, radioiodine therapy or thyroid surgery; immune-modulatory or other medication affecting thyroid function; pregnancy, planned pregnancy or breastfeeding; allergy towards any intervention or placebo component; intake of selenium supplementation >55 μg/day; inability to read or understand Danish or lack of informed consent. The trial will include 2 × 236 participants. The experimental intervention and control groups will receive 200 μg selenium-enriched yeast or matching placebo tablets daily for 12 months. The experimental supplement will be SelenoPrecise®. The primary outcome is thyroid-related quality of life assessed by the Thyroid Patient-Reported Outcome (ThyPRO) questionnaire. Secondary outcomes include serum thyroid peroxidase antibody concentration; serum triiodothyronine/thyroxine ratio; levothyroxine dosage; adverse reactions and serious adverse reactions and events.

DISCUSSION

In this pragmatic trial, participating patients follow their usual treatment at their usual hospitals. In order to collect high-quality data on the clinical course and quality of life, and to minimize missing data, an elaborate trial management system has been designed. 12 months intervention duration was selected in consideration of the primary outcome, thyroid-related quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02013479.

Few items in the thyroid-related quality of life instrument ThyPRO exhibited differential item functioning

OBJECTIVE

To evaluate the extent of differential item functioning (DIF) within the thyroid-specific quality of life patient-reported outcome measure, ThyPRO, according to sex, age, education and thyroid diagnosis.

STUDY DESIGN AND SETTING

A total of 838 patients with benign thyroid diseases completed the ThyPRO questionnaire (84 five-point items, 13 scales). Uniform and nonuniform DIF were investigated using ordinal logistic regression, testing for both statistical significance and magnitude (∆R(2) > 0.02). Scale level was estimated by the sum score, after purification.

RESULTS

Twenty instances of DIF in 17 of the 84 items were found. Eight according to diagnosis, where the goiter scale was the one most affected, possibly due to differing perceptions in patients with auto-immune thyroid diseases compared to patients with simple goiter. Eight DIFs according to age were found, of which 5 were in positively worded items, which younger patients were more likely to endorse; one according to gender: women were more likely to report crying, and three according to educational level. The vast majority of DIF had only minor influence on the scale scores (0.1-2.3 points on the 0-100 scales), but two DIF corresponded to a difference of 4.6 and 9.8, respectively.

CONCLUSION

Ordinal logistic regression identified DIF in 17 of 84 items. The potential impact of this on the present scales was low, but items displaying DIF could be avoided when developing abbreviated scales, where the potential impact of DIF (due to fewer items) will be larger.

Radioiodine therapy in benign thyroid diseases: effects, side effects, and factors affecting therapeutic outcome

Radioiodine ((131)I) therapy of benign thyroid diseases was introduced 70 yr ago, and the patients treated since then are probably numbered in the millions. Fifty to 90% of hyperthyroid patients are cured within 1 yr after (131)I therapy. With longer follow-up, permanent hypothyroidism seems inevitable in Graves' disease, whereas this risk is much lower when treating toxic nodular goiter. The side effect causing most concern is the potential induction of ophthalmopathy in predisposed individuals. The response to (131)I therapy is to some extent related to the radiation dose. However, calculation of an exact thyroid dose is error-prone due to imprecise measurement of the (131)I biokinetics, and the importance of internal dosimetric factors, such as the thyroid follicle size, is probably underestimated. Besides these obstacles, several potential confounders interfere with the efficacy of (131)I therapy, and they may even interact mutually and counteract each other. Numerous studies have evaluated the effect of (131)I therapy, but results have been conflicting due to differences in design, sample size, patient selection, and dose calculation. It seems clear that no single factor reliably predicts the outcome from (131)I therapy. The individual radiosensitivity, still poorly defined and impossible to quantify, may be a major determinant of the outcome from (131)I therapy. Above all, the impact of (131)I therapy relies on the iodine-concentrating ability of the thyroid gland. The thyroid (131)I uptake (or retention) can be stimulated in several ways, including dietary iodine restriction and use of lithium. In particular, recombinant human thyrotropin has gained interest because this compound significantly amplifies the effect of (131)I therapy in patients with nontoxic nodular goiter.

Is Thyroid Autoimmunity per se a Determinant of Quality of Life in Patients with Autoimmune Hypothyroidism?

PURPOSE

To evaluate the relationship between thyroid variables and health-related quality of life (QoL) in patients with autoimmune hypothyroidism, using the thyroid-specific QoL questionnaire ThyPRO.

METHODS

In a cross-sectional study, responses to the ThyPRO from 199 outpatients with autoimmune hypothyroidism were analyzed in relation to thyroid volume, thyroid function and markers of thyroid autoimmunity. Based on a classical QoL framework, we hypothesized that physiological dysfunction caused specific physical and psychological symptoms, which affected functioning and well-being, and consequently participation in life and QoL. These hypotheses were tested through multiple regression and multivariate path analysis models.

RESULTS

None of the thyroid function tests were associated with QoL scores. However, in the pairwise regression, the thyroid peroxidase antibody (TPOAb) level was associated with several QoL outcomes: Goitre Symptoms (p = 0.024), Depressivity (p = 0.004), Anxiety (p = 0.004), Emotional Susceptibility (p = 0.005) and Impaired Social Life (p = 0.047). In the multivariate model, the TPOAb level was related to Goitre Symptoms (r = 0.17, p = 0.019), Depressivity (r = 0.24, p = 0.001), and Anxiety (r = 0.23, p = 0.002), but no longer to Emotional Susceptibility or Impaired Social Life, indicating that the effect on these were mediated through an effect on the symptom scales (i.e. Goitre Symptoms, Depressivity and Anxiety).

CONCLUSION

Health-related QoL, evaluated with state-of-the-art QoL methodology, was related to TPOAb level but not to thyroid function. This raises the hypothesis that autoimmunity, independent of thyroid function, impacts on QoL in patients with autoimmune hypothyroidism, especially in terms of psychological symptoms. Longitudinal studies, in initially untreated patients, are needed to test this hypothesis.

Stressor Scale for Clinical Research Coordinators: development and psychometric testing

AIM

This article is a report of the development and psychometric testing of the Stressor Scale for Clinical Research Coordinators.

BACKGROUND

Job stress is viewed as a situation where working conditions interact with individual worker characteristics and result in disruption of psychological or physiological homeostasis. Clinical research coordinators, also known as research nurses, are professionals who play a central role in clinical trials. They face various problems associated with their responsibilities; however, few studies have reported on their stress. To manage their stress, it is necessary to identify the sources of stress (i.e. stressors).

METHOD

The 56-item preliminary instrument was developed based on literature review and expert discussions. A total of 589 clinical research coordinators in 186 hospitals in Japan were surveyed in 2011. Statistical analyses on construct and concurrent validity, internal consistency, and test-retest reliability were performed.

RESULTS

A six-factor solution with 23 items was selected using exploratory factor analysis: 'quantitative workload', 'conflict with investigators', 'ambiguity of work', 'conflict with other clinical research coordinators and with supervisors', 'demands from an affiliate other than the hospital', and 'difficulty in caring for trial participants'. Confirmatory factor analysis affirmed construct validity, with a demonstrated acceptable fit between the factor structure and the observed data. All factors had significant correlations with burnout and psychological distress, which indicated acceptable concurrent validity. Cronbach's alpha coefficients ranged from 0·73-0·82. Intra-class correlation coefficients indicated almost satisfactory test- retest reliability.

CONCLUSION

Our new instrument has acceptable validity and reliability for evaluating job stressors for clinical research coordinators.

Quality of life is not influenced by the extent of surgery in patients with benign goiter

INTRODUCTION

The surgical approach to benign goiter is becoming increasingly radical due to the risk of recurrent goiter. The aim of this prospective study was to evaluate the impact of surgery on health-related quality of life (HRQoL) of patients with benign goiter.

MATERIAL AND METHODS

HRQoL data from 115 patients with benign goiter were analyzed. Thirty-three patients (group 1) had a hemithyroidectomy. Sixty-five patients (group 2) had a so-called Dunhill operation (hemithyroidectomy + near-total thyroidectomy of the opposite side), and in 17 patients, a total resection of the goiter was performed. The validated HRQoL instrument, the EuroQol-5D, was applied to measure the health-related quality of life.

RESULTS

With an overall complication rate of 10% and no permanent recurrent laryngeal nerve palsy, it was shown that surgery for benign goiter is safe. In the validated HRQoL questionnaire (EQ-5D), no significant variance could be found between different surgical procedures such as thyroidectomy, hemithyroidectomy, or Dunhill procedure. Further, no significant differences in QoL were found in EQ-5D questionnaire compared to normal population.

CONCLUSION

Thyroid surgery can be done safely and without impairment of life quality, regardless of the extent of the operation.

To stimulate or withdraw? A cost-utility analysis of recombinant human thyrotropin versus thyroxine withdrawal for radioiodine ablation in patients with low-risk differentiated thyroid cancer in the United States

CONTEXT

Use of recombinant human TSH (rhTSH) prior to radioactive iodine remnant ablation for patients with differentiated thyroid cancer avoids the hypothyroid state and improves quality of life. European studies have shown that use of rhTSH vs. thyroid hormone withdrawal is a cost-effective method for preparing patients for ablation.

OBJECTIVE

The objective of the study was to determine the cost-utility of rhTSH prior to ablation in the United States.

DESIGN/SETTING/SUBJECTS

A Markov decision model was developed for a hypothetical group of adult patients with low-risk differentiated thyroid cancer who were prepared for ablation by either rhTSH or thyroid hormone withdrawal. Patients entered the model after initial thyroidectomy; follow-up was in accordance with current American Thyroid Association guidelines. Input data were obtained from the literature, Medicare reimbursement schedule, and U.S. Bureau of Labor Statistics. Sensitivity analyses were performed for all clinically relevant inputs.

MAIN OUTCOME MEASURES

Cost-utility, measured in U.S. dollars per quality-adjusted life-year ($/QALY), was measured.

RESULTS

Use of rhTSH yielded an incremental cost-utility of $52,554/QALY (95% confidence interval $52,058-53,050/QALY) (incremental societal cost of $1,365/patient; incremental benefit of 0.026 QALY/patient). The majority of cost and benefit occurs during the preablation, ablation, and postablation period; differences in cost are due to cost of rhTSH and differences in productivity loss (days off work). The model was most sensitive to changes in time off work, cost of rhTSH, and differences in utilities of health states.

CONCLUSIONS

In the United States, the cost-effectiveness of rhTSH for ablation in patients with low-risk differentiated thyroid cancer is highly dependent on potential variations in cost of rhTSH, rates of remnant ablation, time off work, and quality of life.

Validity and reliability of the novel thyroid-specific quality of life questionnaire, ThyPRO

BACKGROUND

Appropriate scale validity and internal consistency reliability have recently been documented for the new thyroid-specific quality of life (QoL) patient-reported outcome (PRO) measure for benign thyroid disorders, the ThyPRO. However, before clinical use, clinical validity and test-retest reliability should be evaluated.

AIM

To investigate clinical ('known-groups') validity and test-retest reliability of the Danish version of the ThyPRO.

METHODS

For each of the 13 ThyPRO scales, we defined groups expected to have high versus low scores ('known-groups'). The clinical validity (known-groups validity) was evaluated by whether the ThyPRO scales could detect expected differences in a cross-sectional study of 907 thyroid patients. Test-retest reliability was evaluated by intra-class correlations of two responses to the ThyPRO 2 weeks apart in a subsample of 87 stable patients.

RESULTS

On all 13 ThyPRO scales, we found substantial and significant differences between the groups expected to have high versus low scores. Test-retest reliability was above 0.70 (range 0.77-0.89) for all scales, which is usually considered necessary for comparisons among patient groups, but below 0.90, which is the usual threshold for use in individual patients.

CONCLUSION

We found support for the clinical validity of the new thyroid-specific QoL questionnaire, ThyPRO, and evidence of good test-retest reliability. The questionnaire is now ready for use in clinical studies of patients with thyroid diseases.