THE INFLAMMATORY BOWEL DISEASE-FATIGUE PATIENT SELF-ASSESSMENT SCALE: TRANSLATION, CROSS-CULTURAL ADAPTATION AND PSYCHOMETRIC PROPERTIES OF THE BRAZILIAN VERSION (IBD-F BRAZIL)

Escala de autoavaliação Inflammatory Bowel Disease-Fatigue: tradução, adaptação cultural e propriedades psicométricas da versão Brasileira (IBD-F Brasil)

ABSTRACT

BACKGROUND:

Fatigue is a common symptom in patients with inflammatory bowel diseases (IBD). A translated and culturally adapted, instrument with robust psychometric for measuring fatigue in Brazilian patients with IBD is needed.

OBJECTIVE:

To translate and cross-culturally adapt the inflammatory Bowel Disease Fatigue Scale (IBD-F) into Brazilian-Portuguese and to test its measurement properties in Brazilian patients with IBD.

METHODS:

Data from 123 patients with IBD were collected. In addition to IBD-F, the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) was used. The measurement properties tested were: internal consistency, reproducibility (reliability and agreement), construct validity, internal and external responsiveness, and ceiling and floor effects.

RESULTS:

The Brazilian-Portuguese version of the IBD-F showed excellent internal consistency (Cronbach’s alpha of 0.95), excellent reproducibility (ICC=0.97) and a minimal detectable change of 6.0 points. The construct validity was demonstrated with a good correlation between the IBD-F and FACIT-F (r=- 0.46). Effect sizes used for measuring internal responsiveness were moderate among those with Crohn’s (0.66) disease and low in patients with ulcerative colitis (0.24). The Brazilian-Portuguese version of the IBD-F presented with high external responsiveness for Crohn’s disease (0.84) and with low external responsiveness for ulcerative colitis (0.33). The area under the curve considered for responsiveness was 0.84. Twenty-five percent of floor effects and no ceiling effect were recorded.

CONCLUSION:

The Brazilian-Portuguese version of IBD-F has adequate measurement properties and its use can be recommended in clinical practice and research.

HEADINGS:
Inflammatory bowel diseases; Reproducibility of results; Fatigue

RESUMO

CONTEXTO:

A fadiga é um sintoma comum em pacientes com doenças inflamatórias intestinais (DII). Um instrumento de avaliação de fadiga traduzido, culturalmente adaptado e com psicometria robusta para medir a fadiga em pacientes brasileiros com DII é necessário.

OBJETIVO:

Traduzir e adaptar culturalmente a Inflammatory Bowel Disease Fatigue Scale (IBD-F) para o português do Brasil e testar suas propriedades de medida em pacientes brasileiros com DII.

MÉTODOS:

Foram coletados dados de 123 pacientes com DII. Além do IBD-F, foi utilizada a Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F). As propriedades de medida testadas foram: consistência interna, reprodutibilidade (confiabilidade e concordância), validade de construto, responsividade interna e externa e efeitos teto e chão.

RESULTADOS:

A versão em português do IBD-F mostrou excelente consistência interna (alfa de Cronbach de 0,95), excelente reprodutibilidade (ICC=0,97) e uma diferença mínima detectável de 6,0 pontos. A validade do construto foi demonstrada por meio de uma boa correlação entre o IBD-F Brasil e o FACIT-F (r= -0,46). Na análise de responsividade interna, os tamanhos de efeito obtidos foram moderado entre aqueles com doença de Crohn (0,66) e baixo em pacientes com colite ulcerativa (0,24). O IBD-F Brasil apresentou alta responsividade externa entre aqueles com doença de Crohn (0,84) e baixa responsividade externa em pacientes colite ulcerativa (0,33). A área sob a curva considerada para responsividade foi de 0,84. Foram registrados 25% de efeito chão e nenhum efeito teto nas avaliações realizadas.

CONCLUSÃO:

O IBD-F Brasil possui propriedades de medida adequadas e seu uso pode ser recomendado na prática clínica e na pesquisa em pacientes com DII.

DESCRITORES:
Doenças inflamatórias intestinais; Reprodutibilidade dos testes; Fadiga

INTRODUCTION

Inflammatory bowel diseases (IBD) are idiopathic multisystemic disorders that present with periods of active and quiescent disease throughout its clinical course^1,2. While ulcerative colitis is characterized by inflammation limited to the colonic mucosa, in Crohn’s disease transmural inflammation can affect any part of the gastrointestinal tract³. In addition to intestinal symptoms, systemic manifestations are common among patients with IBD. General fatigue is a prevalent symptom affecting about 40% of patients in remission and also in about 86% in the active phase of the disease⁴. Fatigue is defined as a feeling of exhaustion, lack of energy, debilitating and of prolonged duration, affecting functional capacity and performance in activities of daily living^5,6. In the IBD diseases, fatigue has been show to be associated with significant impairment in physical function and health-related quality of life^7,8.

In patients with IBD, fatigue has been measured using several scales mostly adapted from those used in chronic diseases trying to determine the patient’s perception and the severity of this symptom⁹. A recent systematic review identified nine different symptom assessment scales used in patients with IBD. The Multidimensional Fatigue Inventory and the Fatigue Impact Scale were the most frequently used instruments⁹, however, the Functional Assessment of Chronic Illness Therapy-Fatigue subscale (FACIT-F) is the only measure validated for use in patients with IBD¹⁰. In addition, the FACIT-F was initially developed to assess the functional consequences of fatigue in cancer patients, not specific for those with IBD.

The Inflammatory Bowel Disease Fatigue (IBD-F) scale was recently developed to evaluate the experience and effects of fatigue in patients with IBD¹¹. The IBD-F measures fatigue symptom considering its most relevant aspects, severity and physical consequences and has robust psychometric properties^12,13,14,15. The prevalence of IBD among Brazilians has been about 0.6 to 6.75 cases/100,000 inhabitants with Crohn’s disease and 2.42 to 21 cases/100,000 inhabitants with ulcerative colitis¹⁶, and an appropriate evaluation of fatigue is crucial to guide better management and intervention for these patients. The IBD-F questionnaire may contribute to the systematic evaluation of fatigue and help to understand its impact on the daily activities of patients with IBD¹¹. The aims of this study were (1) to translate and cross-culturally adapt the IBD-F scale in to Brazilian-Portuguese and (2) to test its measurement properties including internal consistency, reproducibility, construct validity, internal and external responsiveness and ceiling and floor effects in Brazilian patients with IBD.

METHODS

This study was performed in two phases. In Phase I the translation and cross-cultural adaptation of the IBD-F into Brazilian-Portuguese were conducted (IBD-F Brazil). In Phase II the measurement properties of the IBD-F Brazil were explored. Phase I was conducted according to published guidelines for translation and cross-cultural adaptation of health-related questionnaires¹⁷. Phase II applied the quality criteria used for measurement properties of questionnaires¹⁸. The Consensus-based Standards for selection of health status Measurement Instruments (COSMIN) was used as guidance to inform about each measurement property reported¹⁹. An authorization from the author of the IBD-F scale original version was obtained in advance. This study was approved by Human Ethic Committee at Federal University of Juiz de Fora, Minas Gerais, Brazil with the number 2.372.106 (CAAE 68473417.0.0000.5133).

This study was performed at Department of Cardiorespiratory and Musculoskeletal Physiotherapy, Faculty of Physiotherapy, UFJF and at Department of Medicine - Inflammatory Bowel Diseases Center, University Hospital, UFJF.

Phase I - translation and cross-cultural adaptation

The translation and cross-cultural adaptation of the IBD-F were performed in five steps: forward translation, synthesis, backward translation, expert committee review, and pretesting. The forward translation was conducted with the intent to retain the meaning of the original scale. The English version of the IBD-F was translated into Brazilian-Portuguese by two independent native Brazilian Portuguese bilingual and bicultural translators, without previous contact with the instrument. One translator had previous knowledge on health sciences. Both translators emphasized the conceptual rather than the literary translation, and produced two independent versions. Whenever a concept had no equivalent description in the Brazilian culture, the appropriate terms were resolved by consensus between the two translators. None of the original items was omitted. In the synthesis step the independent versions were evaluated and compared for the final consensual Portuguese version. The consensual version in Portuguese was back translated into English by two bilingual professional translators neither aware nor informed of the scale concepts being explored. Both translators did not have medical backgrounds to avoid information bias. The two generated English versions were compared with the original text in English by a Brazilian researcher and a university lecturer, who produced a consensual pre-final version for use in the pretesting step.

During the expert committee review, both forward and backward translations were provided to a committee comprised of five bilingual gastroenterologists. Each Committee member independently analyzed the semantic, idiomatic, experiential, and conceptual equivalence of each item in the IBD-F. None of the items were omitted. In this step, an evaluation was made on the readability of the instrument using the legibility scale of Fernandez-Huerta¹⁸. This scale assesses the reading level which is calculated for each 100-word block of text using the equation: 206.84 - (0.60 x P) - (1.02 x F), where P is the number of syllables and F is the number of sentences per 100 words. This first culturally adapted translation was finalized in three months. In the pretesting step the Brazilian-Portuguese version of the IBD-F was administered to 40 patients with IBD.

Phase II - measurement property assessment

• Participants

Participants were recruited from the Gastroenterology Outpatient Clinic of the Federal University of Juiz de Fora University Hospital (HU/UFJF), Dom Bosco Unit. Participants were included if diagnosed with IBD, aged between 18 and 60 years-old, had clinical, endoscopic and histopathological diagnosis of IBD confirmed by the criteria of Ministry of Health for Crohn’s disease²⁰ and ulcerative colitis²¹. Patients were excluded if have had any alteration of medication or surgical procedure 30 days prior to participation, were unable to understand the study procedures and assessment instruments or were diagnosed with fibromyalgia or any autoimmune, severe cardiorespiratory, neurological or musculoskeletal diseases. All participants provided written informed consent prior to study participation.

• Assessments

The participants’ demographic and clinical characteristics were collected in the first interview. The Harvey-Bradshaw Index²² was used as the clinical index of the disease activity in Crohn’s disease and the Truelove and Witts²³ was used for ulcerative colitis. For Crohn’s disease activity a score of 4 or below was considered as clinical remission while a score of 5 or above considered as the active phase of the disease²⁴. For ulcerative colitis, clinical remission was defined as ≤2 or 3 stools/day, without the presence of blood and/or pus in the stools and no systemic symptoms; mild activity as up to 4 stools/day, with or without blood, no systemic involvement, and increased inflammatory markers; moderate activity as >4 stools per day with minimal systemic symptoms and increased inflammatory markers; and severe activity as >6 stools per day with blood and evidence of systemic involvement, such as fever, tachycardia, anemia, and erythrocyte sedimentation above thirty²³. These disease expression indexes were assessed at baseline, 8 and 12-week follow-up assessments.

Fatigue perception was assessed by FACIT-F, a self-reported scale that comprises of 13 items. The total score ranges from 0 to 52, with higher scores indicating lower fatigue. The FACIT-F scale has been used in clinical populations and is valid for use in the Portuguese language²⁵. Depression and anxiety were assessed by the Hospital Anxiety and Depression Scale (HADS)²⁶. The HADS has 14 anxiety and depression-related questions, seven in each domain. The responses are rated on a 4-point likertscale, ranging from 0 (no impairment) to 3 (highest impairment). The total score ranges from 0 to 21 and a score of 8 or higher is suggestive of anxiety or depression. In addition, participants were asked to filled out the Brazilian Portuguese-language version of the IBD-F scale at three different time-points. The choice of the intervals between testing sessions (48 to 72 hours for reproducibility and 8 to 12 weeks for responsiveness) was based on clinical experts’ opinion, who indicated considerable clinical changes in 8 to 12-week time in patients with IBD.

• Data analysis

The sample size required for Phase II was estimated based on correlation coefficients to explore the association between IBD-F and the FACIT-F. To achieve an alpha value = 0.05 and power of 90% for moderate to recommended correlation coefficients (>0.30), a sample size of 85 subjects was needed. The sample size was increased to 123 subjects allowing for possible loss during follow-up. Data distribution was evaluated using the Kolmogorov-Smirnov test. Normal and non-normal distributed data was expressed as mean and standard deviation (SD) or median and range, respectively. The categorical and dichotomous variables were described in frequency and proportion. The measurement properties tested in this study for the Brazilian-Portuguese version of the IBD-F were: internal consistency, reproducibility (ie. reliability and agreement), content validity, internal and external responsiveness and ceiling and floor effects. The receiver operating characteristic (ROC) curve was used to determine the cut-off point with the most appropriate values for specificity and sensitivity in the IBD-F section I, able to discriminate patients with and without fatigue based on the FACIT-F scores. The data point closest to the curve upper left corner indicated the highest sensitivity and specificity. The Friedman test was used to compare IBD-F score assessed at different timepoints. All analyses were performed using SPSS for Windows version 20.0 (IBM Corporation, Somers, New York, USA).

In addition, each measurement property was tested as recommended¹⁹. The internal consistency (homogeneity) of the IBD-F Brazil was assessed using the Cronbach alpha index and “alpha if item deleted” statistics. The internal consistency analyses the extent to which the items in a given instrument measures different aspects of the same general construct. Estimates greater than 0.70 were considered as adequate²⁷. The reliability and agreement was used as reproducibility assessment. A two-way intraclass correlation coefficient (ICC) using 95% confidence intervals was used for reliability. The ICC was considered low if ≤0.40, moderate if 0.40>ICC<0.75, substantial if 0.75≥ICC<0.90, and excellent if ICC≥0.90²⁸. Agreement between the baseline and the assessment following 48 to 72 hours was evaluated by the standard error of the measurement (SEM). Agreement was obtained by the standard deviation of the difference between test and retest divided by √2. A SEM ≤5% was considered as very good, 5% to 10% as good, 11% to 20% doubtful and >20% as bad agreement²⁷. The minimum detectable change (MDC) was also evaluated to describe the variability associated with participants’ individual scores in the IBD-F and the magnitude of change that a measurement must demonstrate to exceed its anticipated variability. MDC with 95% confidence was calculated using the formula MDC= 1.96/√2 ×SEM)²⁸.

The content validity was analysed by calculating the level of association for scores obtained at baseline between the IBD-F Brazil, the FACIT-F and HADS using the Spearman rho correlation coefficients. The correlation coefficients equal to or greater than 0.60 are recommended; correlations ranging from 0.60 to 0.30 are considered as moderate, and lower than 0.30 as weak associations¹⁸. The internal responsiveness of the IBD-F Brazil was measured using the effect-size. Effect size was obtained using the mean differences between the IBD-F Brazil scores at baseline and at 8 to 12 week follow-up assessment divided by the standard deviation obtained at baseline. Effect sizes indicate the questionnaire’s sensitivity to measure clinical changes, with a score of <0.20 indicate slight, of ≥0.20 to 0.50 as moderate, and of ≥0.80 as a large change²⁷. The effect-size was estimated for all participants and for the Crohn’s disease and ulcerative colitis subgroups separately. To analyse the external responsiveness of the IBD-F Brazil, the correlation between the change score on the Harvey-Bradshaw Index at 8-12 weeks and the baseline assessment was used for the subgroup of patients with Crohn’s disease and the correlation between the change score on the Truelove at 8 to 12 weeks with the change score at 8 to 12 weeks of the IBD-F Brazil for the subgroup of patients with ulcerative colitis. In addition, a receiver-operating-characteristic curve analysis using the FACIT-F was explored. The presence of fatigue was confirmed whenever the IBD-F Brazil cutoff score of 11 points or greater was met. This analysis was based on the area under the curve (AUC), and values ≥0.70 were considered as responsive¹⁸.

The ceiling and floor effects were analysed using the proportion of participants who obtained the maximum and minimum scores of IBD-F Brazil, respectively. Ceiling and floor effects were considered if 15% or more of the respondents achieved the maximum or minimum scores²⁷.

RESULTS

Phase I - translation and cross cultural adaptationof IBD-F

The IBD-F scale was forward and back translated by a professional and a lay translator, any discrepancies were resolved by the expert committee. The expert committee decided to replace item 11 in the Section II, “I had difficulty continuing with my hobbies/interests because of fatigue” to “I had difficulty continuing my leisure activities because of fatigue” and item 12 in the Section II, “My emotional relationship with my partner was affected by fatigue” to “My affective relationship with my partner was affected by fatigue”. These changes were made based on colloquial Brazilian-Portuguese while keeping the same meaning of the sentence. All questions and options answered by 40 patients assessed in Phase I were understandable and applicable to clinical context. The demographic and clinical characteristics of participants included in Phase I and II are summarized in Table 1. The Brazilian-Portuguese versions of the IBD-F did not require additional changes and the number of items and scoring process from the original English versions were maintained, with higher scores indicating higher level of fatigue. The readability in the legibility scale of Fernandez-Huerta was 83.6, which indicate good text readability, appropriate to the target population. The full cross-cultural adaptation process used is described in Figure 1 and the version of the cross-culturally adapted IBD-F Brazil scale is available in Figure 2.

FIGURE 1
IBD-F Brazil.

TABLE 1
Demographic and clinical characteristics of the participants.

	PHASE I (n=40)			PHASE II (n=118)
	CD	UC	Total	CD	UC	Total
Sex (F/M), n	23/11	06/02	29/13	54/27	20/17	74/44
Age (years)	38.1±12	43.1±14.3	39.1±12.0	43.1±11.0	48.9±11.7	44.9±11.8
Disease duration (months)	84±63	100±92	87±69	108±82	132±99	116±88
Disease activity, n (%)
Active	14	-	14 (35)	34	-	34 (29)
Remission	18	-	18 (45)	47	-	47 (39)
Mild	-	4	4 (10)	-	26	26 (22)
Moderate	-	3	3 (7)	-	10	10 (8)
Severe	-	0	0	-	1	1 (1)
Injury extension, n (%)
Colonic	2	-	2 (5)	17	-	17 (14)
Ileocolonic	20	-	20 (50)	33	-	33 (28)
Ileal	9	-	9 (22)	31	-	31 (26)
Mixed	1	-	1 (2)	0	-	0
Distal colitis	-	0	0	-	9	9 (8)
Extensive UC	-	3	3 (7)	-	18	18 (15)
Leftsided UC	-	4	4 (10)	-	10	10 (8)
Phenotype, n (%)
Stricturing	8	-	8 (20)	27	-	27 (22)
Penetrating	6	-	6 (15)	11	-	11 (9)
Inflamatory	8	-	8 (20)	28	-	28 (24)
Mixed	10	-	10 (25)	15	-	15 (13)
FACIT-F	-	-	-	37 (7-52)	46 (11-52)	40 (7-52)
HADS	-	-	-	3 (1-4)	3 (1-4)	3 (1-4)

• Data presented in n (%), mean ±SD and median (range). CD: Crohn’s disease; F: female; FACIT-F: Functional Assessment of Chronic Illness Therapy-Fatigue; HADS: Hospital Anxiety and Depression Scale; M: male; UC: ulcerative colitis.

FIGURE 2
The IBD-F original version, itens and translations, the Brazilian-Portuguese version following consensus, back-translations and the IBD-F Brazil final version.

Phase II of the study - measurement properties testing

A total of 123 participants were assessed on Phase II. The dropout rate was four percent at the third assessment due to loss of patient contact, 118 participants completed the survey (81 patients with Crohn’s disease and 37 with ulcerative colitis). At baseline, participants were asked to complete the IBD-F, the FACIT-F and the HADS instruments. The IBD-F Brazil was also applied following 48 to 72 hours and 8 to 12 weeks following initial assessment. Disease activity was assessed at baseline and at 8 to 12 weeks.

The results of the IBD-F Brazil measurement properties assessed are reported in Table 2. The internal consistency of the IBD-F Brazil was adequate for both Sections of the questionnaire. The Cronbach alpha indexes were 0.95 and 0.98 for Sections I and II, respectively. None of the scale items increased reliability when removed. The IBD-F Brazil indicated excellent reliability with ICC ranging from 0.92 in Section I, 0.97 in Section II and 0.97 in the total score. The SEM for the total score was 4.8 and a MDC of 6.05 points. A significant correlation between IBD-F Brazil scale and the FACIT-F were found -0.60 (rho=-0.67; P<0.001), which confirms the initial hypothesis for convergent validity (Table 2). However, no correlation was found between the IBD-F Brazil and the HADS (rho= 0.14; P=0.12).

TABLE 2
Data of measurement properties testing of the IBD-F Brazil.

Interpretability
IBD-F Brazil score, median (interquartile range)	13.55 (0-48.2)
Minimum score (floor effect), n (%)	29 (25)
Maximum score (ceiling effect), n (%)	0 (0)
Skweness (SE)	0.92 (0.22)
Kurtosis (SE)	-0.14 (0.44)
Internal consistency
Cronbach’s alpha section I	0.95
Cronbach’s alpha section II	0.98
Reproducibility
Reliability
ICC (95% CI) alpha section I	0.92 (0.88-0.97)*
ICC (95% CI) alpha section II	0.97 (0.96-0.98)*
ICC (95% CI) alpha total score	0.97 (0.96-0.98)*
Agreement
SEM	4.8
MDC	6.0
Construct validity
Spearman rho coefficient between IBD-F and FACIT-F	-0.67*
Spearman rho coefficient between IBD-F and HADS	0.14
Internal resposiveness
Effect size for all patients	0.44
Effect size for patients with CD	0.66
Effect size for patients with UC	0.24
External responsiviness
CD subgroup: score change Spearman rho correlation coefficient between IBD-F and HBI	0.84*
UC subgroup: Score change Spearman rho correlation coefficient between IBD-F and Truelove	0.33*
AUC	0.95*

• AUC: area under the curve; CD: Crohn’s disease; CI: confidence interval; FACIT-F: Functional Assessment of Chronic Illness Therapy-Fatigue; HADS: Hospital Anxiety and Depression Scale; HBI: Harvey-Bradshaw index; ICC: intraclass correlation coefficient; MDC: minimal detectable change; SE: standard error; SEM: standard error of the measurement; UC: ulcerative colitis. *P<0.05.

The internal responsiveness were analysed at baseline and following 8 to 12 weeks. The effect sizes for all patients in the IBD-F Brazil were lower (0.44). The effect sizes analyzed for subgroups were moderate for patients with Crohn’s disease (0.66) and low for patients with ulcerative colitis (0.24). The external responsiveness explored on the correlations between the IBD-F Brazil change scores at 8 to 12 weeks and the Harvey-Bradshaw Index change scores for patients with Crohn’s disease were high (r=0.84, P<0.001). The correlation between the IBD-F Brazil change scores at 8 to 12 weeks and the Truelove for patients with ulcerative colitis was low (r=0.24, P<0.001). The ROC curve indicated a cut-off of 11 points to discriminate between patients with presence of fatigue (>11 points) and absence of fatigue, with a sensiti­vity=79.5%, error=3.7%; specificity=77%; and an area under the ROC curve=0.84 [95% CI: 0.77-0.92, P<0.0001].

The ceiling and floor effects recorded were 25% and 0%, respectively. The IBD-F Brazil scores were slightly skewed (Skewness= 0.92 and Kurtosis = -0.14).

The clinical phase of the disease (activity or remission), for both group of patients with Crohn’s disease and ulcerative colitis and the fatigue scores reported in the IBD-F Brazil at different time-points are presented in Table 3. The fatigue scores were higher in patients with active disease compared to those in the remission phase for Crohn’s disease and ulcerative colitis, although patients with Crohn’s also disease reported fatigue symptoms during the remission phase.

TABLE 3
Clinical phase for Crohn’s disease ulcerative colitis and IBD-F Brazil scores at different time-points.

Patient group	Clinical	Baseline	48 to 42 h	8 to 12 w
	phase	n=118	n=118	n=118
IBD-F score - Section I
CD	Remission (n=47)	3.0 (0-17)	1.0 (0-18)	4.0 (0-15)
	Activity (n=34)	13.0 (4-18)	13.0 (6-18)	4.0 (0-12)*
UC	Remission (n=26)	2.5 (0-16)	0.0 (0-12)	0.0 (0-17)
	Activity (n=11)	10.5 (0-17)	11.5 (4-17)	3.0 (0-17)*
IBD-F score - Section II
CD	Remission (n=47)	2.0 (0-81)	0.0 (0-94)	14 (0-81)*
	Activity (n=34)	54.5 (5-100)	50.0 (4-100)	10.5 (0-52)*
UC	Remission (n=26)	0.0 (0-82)	0.0 (0-76)	0.0 (0-93)
	Activity (n=11)	26.5 (0-53)	33.0 (4-59)	5.0 (0-36)*
IBD-F total score
CD	Remission (n=47)	2.0 (0-84)	0.0 (0-97)	15.0 (0-84)*
	Activity (n=34)	51.0 (4-111)	57.3 (6-108)	11.0 (0-58)*
UC	Remission (n=26)	0.0 (0-53)	0.0 (0-81)	0.0 (0-100)
	Activity (n=11)	29.0 (0-55)	34.5 (4-61)	5.0 (0-36)*

• Data are presented as median (min.-max.). CD: Crohn’s disease; IBD-F: inflammatory bowel disease- fatigue; UC: ulcerative colitis. *P<0.01.

DISCUSSION

The main findings of this study were 1) the translational and cross-cultural adaptation Brazilian-Portuguese version of the IBD-F scale and 2) the adequate measurement properties of the IBD-F Brazil to assess fatigue in Brazilian-Portuguese speaking patients. During the translation and cross-cultural adaptation process, only two items from the original version were modified and replaced according to the judgment of the experts committee. The scale was appropriate for and easy to understand by the target population according to legibility scale of Fernandez-Huerta²⁰. Our study demonstrated that the IBD-F Brazil scale has adequate measurement properties to assess fatigue and its effects on daily living activities in patients with IBD.

The IBD-F Brazil achieved a Cronbach’s alpha coefficient of 0.95 and 0.98 for its Section I and for Section II, respectively. These findings were similar to the study of Czuber-Dochan et al.¹¹ of the original English version of the questionnaire. The high internal consistency indicates that all items from IBD-F adequately measure the fatigue construct. The reproducibility of the IBD-F Brazil questionnaire was excellent (ICC: 0.92 for Section I and 0.97 for Section II)¹⁸, and higher than the one reported by Czuber-Dochan et al (ICC: 0.74 for Section I and 0.83 for Section II). This diverging finding on reability observed between the studies may be explained by the different time points established for test-retest in this study, which may have influenced changes in the perception of fatigue. The measurement error of the instrument of 4.8 points in the IBD-F Brazil was very good²⁷. The SEM allows identifying how much variation in the score indicates a real change and provides the MDC, which represents the minimum change in score needed to certify that it was not liable to the instrument error. Our results showed that the magnitude of the change required to exceed the variability of the IBD-F Brazil questionnaire is 6.05 points.

There was a negative correlation between the IBD-F Brazil and the FACIT-F indicating good content validity. Similar findings were observed between the original English version of IBD-F and instruments used to assess fatigue in a general context¹¹. The absence of correlation between the IBD-F Brazil and the HADS scale can be explained by the absence of items assessing physical function in the latter, which can considerably contribute to the increase of anxiety and depression among patients with IBD²⁹. This finding also brings attention to the combined use of the IBD-F and HADS in clinical practice to assure clinicians of a more thorough assessment of physical and mental health in patients with IBD. The effect size was small in Phase II for the whole group, and moderate among patients with Crohn’s disease, which provides evidence of good internal responsiveness of the IBD-F Brazil²⁸. This difference can be explained by the more severe IBD observed in patients with Crohn’s disease who tend o present with more severe symptoms of fatigue due to the varying clinical course of the disease.

The ceiling effect was not detected in the IBD-F Brazil, however, the floor effect was found in 25% of participants. The majority of the investigated patients were in the remission phase of the disease at the baseline, which may have contributed to the lower prevalence of fatigue reported by these participants, particularly in those with ulcerative colitis. The high prevalence of fatigue observed during the active phase of the disease can be explained by higher levels of blood proinflammatory cytokines such as TNF-α³⁰, iron deficiency and anemia, a common symptom reported by patients with IBD due to difficulty of iron absorption. In addition, during the active phase of the disease patients with IBD are prone to fatigue induced by drug therapy such as thiopurines and corticotherapy³¹.

The cut-off point of 11 in the IBD-F Brazil section I had high sensitivity (79.5%) and specificity (77%) in detecting fatigue. This cutoff had adequate discriminatory ability, since patients in the active phase of the disease presented with higher scores than those recorded during the remission phase. The identification of a cut-off for the IBD-F Brazil is clinically relevant as it may help to identify patients with IBD who may benefit from an early intervention to reduce fatigue symptom. Fatigue also reduced from baseline to 8 to 12-week follow-up in patients with active Crohn’s disease and ulcerative colitis by 69.23% and 71.43%, respectively. However, fatigue total score increased from baseline to to 8 to 12-week follow-up in patients with Crohn’s disease in those at the remission phase and did not change in patients with ulcerative colitis. The diverging patterns of fatigue over time confirm the varying clinical course between the two IBD diseases. Although the ongoing systemic inflammation plays a central role in the pathogenesis of fatigue in IBD, the prevalence of fatigue among patients with IBD during clinical remission was 40%³².

This study has limitations. First, the recruitment of participants with IBD was conducted from single center, however, the participant’s characteristics were similar in age and disease duration reported in previous studies also carried out in the general IBD population^4,6,7. Second, the IBD-F was originally self-administered by the study participants. In this study the IBD-F Brazil was evaluated by interview, further studies are required to explore the feasibility of a self-administered version. Finally, an objective measure of muscle fatigue was not used. The associations between the IBD-F Brazil and objective measures of fatigue warrant investigation in future studies.

CONCLUSION

The Brazilian-Portuguese versions of the IBD-F has adequate measurement properties to assess fatigue and its effects on activities of daily living of patients with IBD, particularly in Crohn’s disease. The IBD-F Brazil should be included as part of the clinical assessment of patients with IBD. These findings suggest that the IBD-F Brazil can be used in clinical practice and research.

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• Disclosure of funding: this study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.

Publication Dates

• Publication in this collection
  27 Feb 2020
• Date of issue
  Jan-Mar 2020

History

• Received
  18 Sept 2019
• Accepted
  21 Nov 2019