Langenbecks Arch Surg (2014) 399:755–764 DOI 10.1007/s00423-014-1221-7
ORIGINAL ARTICLE
Improvement of quality of life in patients with benign goiter after surgical treatment Branka R. Bukvic & Vladan R. Zivaljevic & Sandra B. Sipetic & Aleksandar D. Diklic & Katarina M. Tausanovic & Ivan R. Paunovic
Received: 15 March 2014 / Accepted: 18 June 2014 / Published online: 8 July 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose A quality of life (QoL) assessment is considered an important outcome measure in the treatment of benign thyroid diseases. The aims of this study were to analyze the impact of different surgical treatments on QoL in patients with benign thyroid diseases and to evaluate factors correlating with the QoL outcomes. Methods A prospective longitudinal study was conducted. One hundred thirty-two patients met the inclusion/exclusion criteria and completed the disease-specific questionnaire, thyroid patient-reported outcome (ThyPRO), before surgery and after 6 months. Preoperative and postoperative QoL outcomes were compared and correlating factors were analyzed. Results Indication for surgery was euthyroid goiter, toxic goiter, and suspicious malignant thyroid disease in 58.3, 29.5, and 12.1 % of the patients, respectively. None of the patients had overtly toxic goiter. There were 65.2 % of the patients who underwent total thyroidectomy, while 34.8 % underwent hemithyroidectomy. The total postoperative complication rate was 5.3 %. QoL improved significantly after surgical treatment, independent of the extent of performed surgery. The most affected domain, pre- and postoperative, was for tiredness. QoL improvement was significant for women in all domains, while for men, it was significant in only B. R. Bukvic : S. B. Sipetic Institute for Epidemiology, Faculty of Medicine, University of Belgrade, Visegradska 26, Belgrade 11000, Serbia B. R. Bukvic (*) General Hospital Uzice, Health Center Uzice, Milosa Obrenovica 17, Uzice 31000, Serbia e-mail: [email protected] V. R. Zivaljevic : A. D. Diklic : K. M. Tausanovic : I. R. Paunovic Faculty of Medicine, Center for Endocrine Surgery, Clinical Center of Serbia, University of Belgrade, Koste Todorovica 8, Belgrade 11000, Serbia
three domains (goiter symptoms, emotional susceptibility, and cosmetic complaints) and in overall QoL. Younger patients had significantly better cognitive functioning and daily life, while elderly patients had significantly less cosmetic complaints. The factors that significantly correlated with improvement of QoL in different domains were lower education level, duration of disease, and microcarcinoma at final histology. Conclusion QoL in patients with benign thyroid diseases improves significantly after operative treatment, independent of the extent of the operation. Keywords Benign goiter . Thyroidectomy . Hemithyroidectomy . Quality of life
Introduction Thyroid diseases are common and the most common are benign thyroid diseases. They occur at all ages in both sexes, but are 5 to 10 times more likely to occur in females than in males [1–3]. Benign thyroid diseases are almost never lifethreatening but they may impact patients’ quality of life (QoL). The treatment for thyroid diseases should lead to preservation, at the very least and, if possible, improvement of the patient’s QoL. There are more than one treatment options for patients with benign thyroid diseases. One of the treatment options is surgery. The measurement of QoL is an important outcome assessment in trials dealing with the health of individuals after surgical treatment [4–6]. There are two types of questionnaires that are used for evaluating QoL: generic QoL questionnaires and diseasespecific QoL questionnaires. A generic questionnaire can be applied across a wide range of populations and interventions. The disease-specific questionnaires are designed to measure the impact of a particular disease on patients’ QoL, and they are more sensitive to smaller changes over time than generic
756
questionnaires. Both questionnaires are important in clinical trials because they provide complementary information. Questions from generic questionnaires are most often incorporated in disease-specific questionnaires [7]. Thyroid patient-reported outcome (ThyPRO) is a recently developed, disease-specific QoL questionnaire that is validated and standardized to measure the QoL of patients with every kind of benign thyroid disease. This is the only QoL questionnaire that is applicable to patients with different benign thyroid diseases. It was developed by Watt et al. in Denmark. It has been translated into several languages and validated [6, 8–11]. In collaboration with the developer, we translated and validated the questionnaire in Serbian. There are many published data on impaired QoL of patients with thyroid dysfunction and patients with thyroid carcinoma [12–16]. The impact of Graves’ disease and Hashimoto thyroiditis (as a group of autoimmune diseases) on QoL has also been studied [17–21]. However, the impact of goiters on patients without overt thyroid dysfunction and the impact of thyroidectomy on all aspects of a patient’s life, including physical, mental, social, and cognitive functioning, have not been adequately studied. Most of the published studies that investigated postoperative QoL in patients with benign goiter used generic QoL questionnaires, which are less sensitive than specific ones [22, 23]. This might have been due to a lack of validated disease-specific QoL measurements until recently [6]. Published data indicate that surgery, as a treatment option, leads to QoL improvement in patients with benign goiters [22–24]. We have found just three published studies dealing with this issue, of which two used generic QoL measures [22, 23], and one, the last published, used ThyPRO [23]. None of the previously published studies excluded patients with Graves’ disease, which may have a greater influence on patients’ QoL than other benign goiters [22–24]. Also, in one of the studies, patients with differentiated thyroid carcinoma were not excluded from the study [22]. The aims of the present study were to evaluate the impact of surgical treatment on QoL in patients with nonautoimmune benign goiters and to analyze possible important correlating factors.
Patients and methods Patient population We conducted a prospective longitudinal case-control study with patients with benign goiters. The study was conducted at the Center for Endocrine Surgery, Clinical Center of Serbia, in Belgrade. The Center for Endocrine Surgery is a tertiary care referral center for endocrine diseases where four endocrine surgeons and three residents perform about 720 thyroid surgeries per year. All patients in the study underwent thyroid surgery at the Center for Endocrine Surgery over two time
Langenbecks Arch Surg (2014) 399:755–764
periods: April 2012 to August 2012 and January 2013 to July 2013. Patients were asked to participate in the study if they met the inclusion/exclusion criteria. Inclusion criteria were as follows: – –
Age between 18 and 75 years Benign nonautoimmune or suspicious goiter Exclusion criteria were as follows:
– – – – –
–
History of brain injuries (traumatic or organic) Malignancy at other location History of psychiatric conditions Graves’ disease (hyperthyroidism with diffuse goiter and increased thyroid-stimulating hormone receptor antibodies (TRAb), with or without exophthalmos) Hashimoto thyroiditis (hypothyroidism, or less often hyperthyroid and euthyroid goiter, with elevated thyroid peroxidase antibody levels (anti-TPO) and/or Hashimoto thyroiditis on final histology) Thyroid carcinoma on final histology (except incidental thyroid microcarcinoma)
Initially, 201 patients who completed the baseline assessment agreed to participate in the study and were enrolled. Sixty-seven patients were excluded from the study: 8 patients had inoperable thyroid disease (7 had anaplastic thyroid carcinoma and 1 had a lymphoma), 40 patients were found to have malignant disease on histological examination, and 19 patients, who were not diagnosed preoperatively to have Hashimoto thyroiditis, were found to have Hashimoto thyroiditis after histological examination. One patient died and one patient did not wish to continue to participate in the study. Ultimately, the study group consisted of 132 subjects. Surgical treatment The assessment and the management plan for the patients were carried out according to the department’s standard protocol. Patients were admitted to the hospital 1 day prior to the planned surgery; drains were removed on the first postoperative day, and if no complications (postoperative bleeding, severe hypocalcemia, or a bilateral recurrent laryngeal nerve (RLN) paralysis) occurred, patients were discharged on the third postoperative day. Patients brought their laboratory findings with them on their day of admission to the hospital. The findings could not be older than 1 month and were obligatory, including total serum thyroxine (T4) or free thyroxine (fT4), total serum triiodothyronine (T3) or free triiodothyronine (fT3), thyroid-stimulating hormone (TSH), and serum calcitonin levels. If the basal calcitonin level was elevated, a calcium loading test was performed. When required, patients brought findings of their serum antithyroid antibodies. All
Langenbecks Arch Surg (2014) 399:755–764
patients brought ultrasonographic (US) examination findings of the neck and an indirect laryngoscopy assessment of vocal cord function. All patients brought an X-ray of their trachea. If fine needle aspiration (FNA) was performed preoperatively, patients brought their cytology findings. FNA was not obligatory in patients with a nonsuspicious ultrasound appearance of the thyroid gland, nonsuspicious iodine-131 scintigraphy findings, and nonsuspicious clinical findings. According to local standard protocols, patients with euthyroid multinodular goiter (euthyroid patients with ultrasonography findings of nodules in the thyroid gland and benign FNA cytology findings, if performed), toxic multinodular goiter (patients with US findings of nodules in the thyroid gland, with iodine-131 scintigraphy findings of warm thyroid nodules and who were receiving antithyroid drugs or had suppressed TSH levels), and suspicious goiter (suspicious FNA cytology findings or elevated calcitonin level) underwent a total thyroidectomy. In patients with suspicious goiter, where intraoperative findings were also suspicious, a sentinel lymph node biopsy was performed (a biopsy of the first lymph node draining a thyroid gland lobe in which the suspicious nodule was found). Patients with toxic adenoma (autonomously functioning toxic nodule with iodine-131 scintigraphy finding of a warm thyroid nodule) and nodular goiter (euthyroid patients with ultrasonography findings of one thyroid nodule, unsuspicious FNA finding, calcitonin level within normal range) underwent a hemithyroidectomy. According to local standard protocols, calcium and phosphate levels were measured in all patients on the first, second, and third postoperative days. In patients with low calcium and high phosphate levels, calcium replacement therapy was administered for 1 month. After that period of time, we controlled calcium and phosphate levels and evaluated clinical signs of hypocalcemia (Chvostek’s and Trousseau’s sign) periodically, and calcium therapy was gradually discontinued. According to local standard protocol, if patients still required calcium supplementation therapy 3 months after surgery, the parathyroid hormone level was measured. In patients who were hoarse after surgery, vocal cord function was assessed by indirect laryngoscopy, 1 and 6 months after surgery. Thyroid supplementation therapy was initiated 3 days after surgery in all patients, except those who underwent a hemithyroidectomy for toxic adenoma, according to local standards of care. Thyroid supplementation therapy was prescribed to patients who were hemithyroidectomized for nontoxic nodular goiter aiming to protect the other thyroid lobe from enlargement and hyperfunctioning. Thyroid supplementation therapy was not prescribed to patients hemithyroidectomized for toxic adenoma in order to check whether the other thyroid lobe was normally functioning.
757
Questionnaires The survey consisted of two parts. The first part contained questions referring to patients’ sociodemographic characteristics such as sex, age, education, marital status and socioeconomic status, and health habits (smoking habits and alcohol consumption). The second part consisted of a disease-specific QoL measurement, the ThyPRO questionnaire. ThyPRO consists of 85 items covering physical and mental symptoms, well-being and function, as well as the impact of thyroid disease on participation (i.e., social and daily life) and overall QoL. Items were grouped in 13 scales (goiter symptoms, hyperthyroid symptoms, hypothyroid symptoms, eye symptoms, tiredness, cognitive impairment, anxiety, depression, emotional susceptibility, impaired social life, impaired daily life, impaired sex life, cosmetic complaints) and one single item, overall QoL. Each of the 13 ThyPRO scales was scored as a summary score and linearly transformed to range 0–100 with increasing scores indicating decreasing QoL (i.e., more symptoms or greater impact of disease) and lower scores indicating better QoL. In addition, ThyPRO contains one item not included in any multi-item scale that relates to overall QoL. According to the internationally accepted methodology for translation and cultural adaptation of a QoL questionnaire, we have followed the guidelines set up by the EORTC group for the production of the Serbian version of ThyPRO [25]. This translation involved the following steps: (1) two independent translations of the English version of the ThyPRO questionnaire into Serbian, performed by two independent professional translators with excellent English knowledge whose native language is Serbian. (2) The better translation was chosen as the “forward translation” by the coordinator. (3) In the “backward translation” step, the “forward translation” was translated back into English by a professional with excellent knowledge of Serbian whose native language is English. The developer of ThyPRO, a Serbian coordinator, two qualified translators, clinicians, and epidemiologist have discussed controversial items to generate a version of the ThyPRO which would be the most appropriate for the cultural environment of Serbia and acceptable for testing on thyroid patients. (4) In order to check the Serbian population’s understanding and interpretation of the translated items, the questionnaire was tested on five thyroid patients by an appropriate translation consultant recruit from Health Research Associates (HRA). The results of these tests have been discussed by the same group of experts. This stage led to the final Serbian version of ThyPROsr. All questionnaires were administrated by qualified physicians, who were dealing with endocrine surgery and the quality of life assessment, in person. The patients were asked to complete the questionnaire twice: first when they were admitted to the department for thyroid surgery and again 6 months later. The physician who assisted the patient with
758
completion of the postoperative ThyPROsr questionnaire did not have access to the preoperative questionnaire or scores. All other necessary data (hormonal levels, antithyroid antibody levels, histological findings, duration of disease, and complications after surgery) were collected from the medical charts. This study was conducted with the approval of the Ethics Committee of the Faculty of Medicine, University of Belgrade, and written informed consent was obtained from all patients prior to their inclusion in the study.
Langenbecks Arch Surg (2014) 399:755–764 Table 1 Sociodemographic characteristics of the sample Age (years), mean ± SD (median) Gender Marital status
Level of education
Statistics Tobacco smoker
A statistical analysis was conducted using SPSS 16.0. We used descriptive statistics for sociodemographic and clinical characteristics. Mean preoperative and postoperative scores of each domain of ThyPRO and overall QoL were calculated as previously described. QoL improvement after surgery was calculated as the difference between preoperative and postoperative scores of each domain and overall QoL, with higher results presenting greater improvement and lower results presenting less improvement. Continuous data were described by mean, standard deviation, and median values. Categorical data were described by frequencies. Since the distribution of tested continuous variables was not normal, nonparametric tests were used in the statistical analysis. The Wilcoxon signed ranks test was used to compare two related variables: preoperative versus postoperative ThyPRO scores. The MannWhitney U test was used to compare two independent variables (ThyPRO scores between different subgroups of the sample). The Kruskal-Wallis test was used to compare more independent variables (ThyPRO scores among different subgroups of the sample). A nonparametric correlation test (Spearman’s ρ correlation test) was used to analyze factors that correlate with different domains of QoL. The difference was considered as highly significant if p
ORIGINAL ARTICLE
Improvement of quality of life in patients with benign goiter after surgical treatment Branka R. Bukvic & Vladan R. Zivaljevic & Sandra B. Sipetic & Aleksandar D. Diklic & Katarina M. Tausanovic & Ivan R. Paunovic
Received: 15 March 2014 / Accepted: 18 June 2014 / Published online: 8 July 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose A quality of life (QoL) assessment is considered an important outcome measure in the treatment of benign thyroid diseases. The aims of this study were to analyze the impact of different surgical treatments on QoL in patients with benign thyroid diseases and to evaluate factors correlating with the QoL outcomes. Methods A prospective longitudinal study was conducted. One hundred thirty-two patients met the inclusion/exclusion criteria and completed the disease-specific questionnaire, thyroid patient-reported outcome (ThyPRO), before surgery and after 6 months. Preoperative and postoperative QoL outcomes were compared and correlating factors were analyzed. Results Indication for surgery was euthyroid goiter, toxic goiter, and suspicious malignant thyroid disease in 58.3, 29.5, and 12.1 % of the patients, respectively. None of the patients had overtly toxic goiter. There were 65.2 % of the patients who underwent total thyroidectomy, while 34.8 % underwent hemithyroidectomy. The total postoperative complication rate was 5.3 %. QoL improved significantly after surgical treatment, independent of the extent of performed surgery. The most affected domain, pre- and postoperative, was for tiredness. QoL improvement was significant for women in all domains, while for men, it was significant in only B. R. Bukvic : S. B. Sipetic Institute for Epidemiology, Faculty of Medicine, University of Belgrade, Visegradska 26, Belgrade 11000, Serbia B. R. Bukvic (*) General Hospital Uzice, Health Center Uzice, Milosa Obrenovica 17, Uzice 31000, Serbia e-mail: [email protected] V. R. Zivaljevic : A. D. Diklic : K. M. Tausanovic : I. R. Paunovic Faculty of Medicine, Center for Endocrine Surgery, Clinical Center of Serbia, University of Belgrade, Koste Todorovica 8, Belgrade 11000, Serbia
three domains (goiter symptoms, emotional susceptibility, and cosmetic complaints) and in overall QoL. Younger patients had significantly better cognitive functioning and daily life, while elderly patients had significantly less cosmetic complaints. The factors that significantly correlated with improvement of QoL in different domains were lower education level, duration of disease, and microcarcinoma at final histology. Conclusion QoL in patients with benign thyroid diseases improves significantly after operative treatment, independent of the extent of the operation. Keywords Benign goiter . Thyroidectomy . Hemithyroidectomy . Quality of life
Introduction Thyroid diseases are common and the most common are benign thyroid diseases. They occur at all ages in both sexes, but are 5 to 10 times more likely to occur in females than in males [1–3]. Benign thyroid diseases are almost never lifethreatening but they may impact patients’ quality of life (QoL). The treatment for thyroid diseases should lead to preservation, at the very least and, if possible, improvement of the patient’s QoL. There are more than one treatment options for patients with benign thyroid diseases. One of the treatment options is surgery. The measurement of QoL is an important outcome assessment in trials dealing with the health of individuals after surgical treatment [4–6]. There are two types of questionnaires that are used for evaluating QoL: generic QoL questionnaires and diseasespecific QoL questionnaires. A generic questionnaire can be applied across a wide range of populations and interventions. The disease-specific questionnaires are designed to measure the impact of a particular disease on patients’ QoL, and they are more sensitive to smaller changes over time than generic
756
questionnaires. Both questionnaires are important in clinical trials because they provide complementary information. Questions from generic questionnaires are most often incorporated in disease-specific questionnaires [7]. Thyroid patient-reported outcome (ThyPRO) is a recently developed, disease-specific QoL questionnaire that is validated and standardized to measure the QoL of patients with every kind of benign thyroid disease. This is the only QoL questionnaire that is applicable to patients with different benign thyroid diseases. It was developed by Watt et al. in Denmark. It has been translated into several languages and validated [6, 8–11]. In collaboration with the developer, we translated and validated the questionnaire in Serbian. There are many published data on impaired QoL of patients with thyroid dysfunction and patients with thyroid carcinoma [12–16]. The impact of Graves’ disease and Hashimoto thyroiditis (as a group of autoimmune diseases) on QoL has also been studied [17–21]. However, the impact of goiters on patients without overt thyroid dysfunction and the impact of thyroidectomy on all aspects of a patient’s life, including physical, mental, social, and cognitive functioning, have not been adequately studied. Most of the published studies that investigated postoperative QoL in patients with benign goiter used generic QoL questionnaires, which are less sensitive than specific ones [22, 23]. This might have been due to a lack of validated disease-specific QoL measurements until recently [6]. Published data indicate that surgery, as a treatment option, leads to QoL improvement in patients with benign goiters [22–24]. We have found just three published studies dealing with this issue, of which two used generic QoL measures [22, 23], and one, the last published, used ThyPRO [23]. None of the previously published studies excluded patients with Graves’ disease, which may have a greater influence on patients’ QoL than other benign goiters [22–24]. Also, in one of the studies, patients with differentiated thyroid carcinoma were not excluded from the study [22]. The aims of the present study were to evaluate the impact of surgical treatment on QoL in patients with nonautoimmune benign goiters and to analyze possible important correlating factors.
Patients and methods Patient population We conducted a prospective longitudinal case-control study with patients with benign goiters. The study was conducted at the Center for Endocrine Surgery, Clinical Center of Serbia, in Belgrade. The Center for Endocrine Surgery is a tertiary care referral center for endocrine diseases where four endocrine surgeons and three residents perform about 720 thyroid surgeries per year. All patients in the study underwent thyroid surgery at the Center for Endocrine Surgery over two time
Langenbecks Arch Surg (2014) 399:755–764
periods: April 2012 to August 2012 and January 2013 to July 2013. Patients were asked to participate in the study if they met the inclusion/exclusion criteria. Inclusion criteria were as follows: – –
Age between 18 and 75 years Benign nonautoimmune or suspicious goiter Exclusion criteria were as follows:
– – – – –
–
History of brain injuries (traumatic or organic) Malignancy at other location History of psychiatric conditions Graves’ disease (hyperthyroidism with diffuse goiter and increased thyroid-stimulating hormone receptor antibodies (TRAb), with or without exophthalmos) Hashimoto thyroiditis (hypothyroidism, or less often hyperthyroid and euthyroid goiter, with elevated thyroid peroxidase antibody levels (anti-TPO) and/or Hashimoto thyroiditis on final histology) Thyroid carcinoma on final histology (except incidental thyroid microcarcinoma)
Initially, 201 patients who completed the baseline assessment agreed to participate in the study and were enrolled. Sixty-seven patients were excluded from the study: 8 patients had inoperable thyroid disease (7 had anaplastic thyroid carcinoma and 1 had a lymphoma), 40 patients were found to have malignant disease on histological examination, and 19 patients, who were not diagnosed preoperatively to have Hashimoto thyroiditis, were found to have Hashimoto thyroiditis after histological examination. One patient died and one patient did not wish to continue to participate in the study. Ultimately, the study group consisted of 132 subjects. Surgical treatment The assessment and the management plan for the patients were carried out according to the department’s standard protocol. Patients were admitted to the hospital 1 day prior to the planned surgery; drains were removed on the first postoperative day, and if no complications (postoperative bleeding, severe hypocalcemia, or a bilateral recurrent laryngeal nerve (RLN) paralysis) occurred, patients were discharged on the third postoperative day. Patients brought their laboratory findings with them on their day of admission to the hospital. The findings could not be older than 1 month and were obligatory, including total serum thyroxine (T4) or free thyroxine (fT4), total serum triiodothyronine (T3) or free triiodothyronine (fT3), thyroid-stimulating hormone (TSH), and serum calcitonin levels. If the basal calcitonin level was elevated, a calcium loading test was performed. When required, patients brought findings of their serum antithyroid antibodies. All
Langenbecks Arch Surg (2014) 399:755–764
patients brought ultrasonographic (US) examination findings of the neck and an indirect laryngoscopy assessment of vocal cord function. All patients brought an X-ray of their trachea. If fine needle aspiration (FNA) was performed preoperatively, patients brought their cytology findings. FNA was not obligatory in patients with a nonsuspicious ultrasound appearance of the thyroid gland, nonsuspicious iodine-131 scintigraphy findings, and nonsuspicious clinical findings. According to local standard protocols, patients with euthyroid multinodular goiter (euthyroid patients with ultrasonography findings of nodules in the thyroid gland and benign FNA cytology findings, if performed), toxic multinodular goiter (patients with US findings of nodules in the thyroid gland, with iodine-131 scintigraphy findings of warm thyroid nodules and who were receiving antithyroid drugs or had suppressed TSH levels), and suspicious goiter (suspicious FNA cytology findings or elevated calcitonin level) underwent a total thyroidectomy. In patients with suspicious goiter, where intraoperative findings were also suspicious, a sentinel lymph node biopsy was performed (a biopsy of the first lymph node draining a thyroid gland lobe in which the suspicious nodule was found). Patients with toxic adenoma (autonomously functioning toxic nodule with iodine-131 scintigraphy finding of a warm thyroid nodule) and nodular goiter (euthyroid patients with ultrasonography findings of one thyroid nodule, unsuspicious FNA finding, calcitonin level within normal range) underwent a hemithyroidectomy. According to local standard protocols, calcium and phosphate levels were measured in all patients on the first, second, and third postoperative days. In patients with low calcium and high phosphate levels, calcium replacement therapy was administered for 1 month. After that period of time, we controlled calcium and phosphate levels and evaluated clinical signs of hypocalcemia (Chvostek’s and Trousseau’s sign) periodically, and calcium therapy was gradually discontinued. According to local standard protocol, if patients still required calcium supplementation therapy 3 months after surgery, the parathyroid hormone level was measured. In patients who were hoarse after surgery, vocal cord function was assessed by indirect laryngoscopy, 1 and 6 months after surgery. Thyroid supplementation therapy was initiated 3 days after surgery in all patients, except those who underwent a hemithyroidectomy for toxic adenoma, according to local standards of care. Thyroid supplementation therapy was prescribed to patients who were hemithyroidectomized for nontoxic nodular goiter aiming to protect the other thyroid lobe from enlargement and hyperfunctioning. Thyroid supplementation therapy was not prescribed to patients hemithyroidectomized for toxic adenoma in order to check whether the other thyroid lobe was normally functioning.
757
Questionnaires The survey consisted of two parts. The first part contained questions referring to patients’ sociodemographic characteristics such as sex, age, education, marital status and socioeconomic status, and health habits (smoking habits and alcohol consumption). The second part consisted of a disease-specific QoL measurement, the ThyPRO questionnaire. ThyPRO consists of 85 items covering physical and mental symptoms, well-being and function, as well as the impact of thyroid disease on participation (i.e., social and daily life) and overall QoL. Items were grouped in 13 scales (goiter symptoms, hyperthyroid symptoms, hypothyroid symptoms, eye symptoms, tiredness, cognitive impairment, anxiety, depression, emotional susceptibility, impaired social life, impaired daily life, impaired sex life, cosmetic complaints) and one single item, overall QoL. Each of the 13 ThyPRO scales was scored as a summary score and linearly transformed to range 0–100 with increasing scores indicating decreasing QoL (i.e., more symptoms or greater impact of disease) and lower scores indicating better QoL. In addition, ThyPRO contains one item not included in any multi-item scale that relates to overall QoL. According to the internationally accepted methodology for translation and cultural adaptation of a QoL questionnaire, we have followed the guidelines set up by the EORTC group for the production of the Serbian version of ThyPRO [25]. This translation involved the following steps: (1) two independent translations of the English version of the ThyPRO questionnaire into Serbian, performed by two independent professional translators with excellent English knowledge whose native language is Serbian. (2) The better translation was chosen as the “forward translation” by the coordinator. (3) In the “backward translation” step, the “forward translation” was translated back into English by a professional with excellent knowledge of Serbian whose native language is English. The developer of ThyPRO, a Serbian coordinator, two qualified translators, clinicians, and epidemiologist have discussed controversial items to generate a version of the ThyPRO which would be the most appropriate for the cultural environment of Serbia and acceptable for testing on thyroid patients. (4) In order to check the Serbian population’s understanding and interpretation of the translated items, the questionnaire was tested on five thyroid patients by an appropriate translation consultant recruit from Health Research Associates (HRA). The results of these tests have been discussed by the same group of experts. This stage led to the final Serbian version of ThyPROsr. All questionnaires were administrated by qualified physicians, who were dealing with endocrine surgery and the quality of life assessment, in person. The patients were asked to complete the questionnaire twice: first when they were admitted to the department for thyroid surgery and again 6 months later. The physician who assisted the patient with
758
completion of the postoperative ThyPROsr questionnaire did not have access to the preoperative questionnaire or scores. All other necessary data (hormonal levels, antithyroid antibody levels, histological findings, duration of disease, and complications after surgery) were collected from the medical charts. This study was conducted with the approval of the Ethics Committee of the Faculty of Medicine, University of Belgrade, and written informed consent was obtained from all patients prior to their inclusion in the study.
Langenbecks Arch Surg (2014) 399:755–764 Table 1 Sociodemographic characteristics of the sample Age (years), mean ± SD (median) Gender Marital status
Level of education
Statistics Tobacco smoker
A statistical analysis was conducted using SPSS 16.0. We used descriptive statistics for sociodemographic and clinical characteristics. Mean preoperative and postoperative scores of each domain of ThyPRO and overall QoL were calculated as previously described. QoL improvement after surgery was calculated as the difference between preoperative and postoperative scores of each domain and overall QoL, with higher results presenting greater improvement and lower results presenting less improvement. Continuous data were described by mean, standard deviation, and median values. Categorical data were described by frequencies. Since the distribution of tested continuous variables was not normal, nonparametric tests were used in the statistical analysis. The Wilcoxon signed ranks test was used to compare two related variables: preoperative versus postoperative ThyPRO scores. The MannWhitney U test was used to compare two independent variables (ThyPRO scores between different subgroups of the sample). The Kruskal-Wallis test was used to compare more independent variables (ThyPRO scores among different subgroups of the sample). A nonparametric correlation test (Spearman’s ρ correlation test) was used to analyze factors that correlate with different domains of QoL. The difference was considered as highly significant if p
