ORIGINAL ARTICLE

Validation of a Persian version of the Fibromyalgia ImpactQuestionnaire (FIQ-P)

Ali Bidari • Morteza Hassanzadeh •

Mohamad-Farzam Mohabat • Elham Talachian •

Effat Merghati Khoei

Received: 18 July 2013 / Accepted: 11 October 2013 / Published online: 29 October 2013

� Springer-Verlag Berlin Heidelberg 2013

Abstract The aim of this study is to translate, adapt, and

validate a Persian version of the Fibromyalgia (FM) Impact

Questionnaire (FIQ-P). The FIQ-P was adapted following the

translation and back-translation approach; then, it was

administered to thirty females with FM. Participants also

completed two other validated questionnaires, the Medical

Outcome Survey Short Form-36 (SF-36) and the Beck

Depression Inventory (BDI). Internal consistency within the

FIQ-P items and its test–retest reliability were assessed with

Cronbach’s alpha and Spearman’s correlation coefficient,

respectively. Construct validity was analyzed by Spearman’s

r when correlating the FIQ-P to other questionnaires. The

translated version was concordant. Adaptation affected two

sub-items of physical function. Participants’ mean

age ± standard deviation was 40.4 ± 9.0 years. Internal

consistency proved good with a = 0.80. Test–retest coeffi-

cient ranged from 0.50 for the item ‘‘work days missed’’ to 0.79

for all FIQ-P items. Fair and statistically significant (P \ 0.01)

correlations were found between the FIQ-P items and two

other questionnaires, SF-36 (r = -0.57) and BDI (r = 0.53).

We concluded that the FIQ-P is a valid and reliable instrument

for measuring health status of Persian-speaking FM patients.

Keywords Fibromyalgia Impact Questionnaire �Validation studies � Persian � Iran

Introduction

Fibromyalgia (FM) is a common clinical entity that affects

2–3 % of population and is characterized by widespread

body pain as the pivot symptom, as well as other somatic

complaints including fatigue, anxiety, non-restorative

sleep, and cognitive problems [1–7].

The FM syndrome is of major interest for exerting sig-

nificant impact on general health status and activity of

daily living in affected patients [8]. Clinical tools to mea-

sure the consequences of FM in personal and social life of

patients are critical for clinical, epidemiological, and out-

come studies and are useful for following the response to

treatment interventions [9].

For FM syndrome, there are several outcome measure

questionnaires, validated in English language, which are

employed to assess different aspects of overall health and

function of the patients [10]. The Arthritis Impact Mea-

surement Scale (AIMS) [11], the Health Assessment

Questionnaire (HAQ) [12], the Medical Outcome Survey

Short Form-36 (SF-36) [13], and the Fibromyalgia Impact

Questionnaire (FIQ) [14] are among many widely accepted

instruments [15].

A. Bidari

Department of Rheumatology, Iran University of Medical

Sciences, Tehran, Iran

M. Hassanzadeh

Department of Internal Medicine, Iran University of Medical

Sciences, Tehran, Iran

M.-F. Mohabat

Medical Laser Research Center, Iranian Center for Medical

Laser (ICML), Academic Center for Education, Culture and

Research (ACECR), Tehran, Iran

E. Talachian

Division of Pediatric Gastroenterology, Iran University of

Medical Sciences, Tehran, Iran

E. M. Khoei (&)

Brain and Spinal Cord Injury Research Center (BASIR), Iranian

National Center of Addiction Studies (INCAS), Tehran

University of Medical Sciences, Buiding No. 486, Ghazvin

Square, South Karegar Street, Tehran, Iran

e-mail: effat_mer@tums.ac.ir

123

Rheumatol Int (2014) 34:181–189

DOI 10.1007/s00296-013-2883-0

As a protean clinical condition, FM is modulated by

many environmental, genetic, and epidemiological factors

[16], mandating field research in different geographical and

cultural settings. Correspondingly, translation and valida-

tion of standardized questionnaires is essential for the best

evidence-based practice in various societies.

The FIQ, as the most widely used outcome measure tool

for FM, was first developed by Burckhardt et al. [14]. It has

been translated into many languages, and the Arabic [17],

Dutch [18], French [19], German [20], Italian [21], Japa-

nese [22], Spanish [23], Swedish [24], Korean [25], and

Turkish [26] versions proved to have psychometric prop-

erties, validity, and reliability that are comparable to the

original version.

In order to join this international development, we

designed this study to make a Persian version of the FIQ

(FIQ-P) and to evaluate its validity and reliability for being

used in a Persian-speaking population.

Materials and methods

Patient selection

Study subjects were recruited from FM cases attending the

pain clinic at Medical Laser Research center, Iranian

Center for Medical Laser (ICML), Academic Center for

Education, Culture and Research (ACECR), Tehran, Iran.

All enrolled patients were females, aged between 18 and

65 years, who fulfilled the American Colleague of Rheu-

matology (ACR) 1990 classification criteria for FM [27].

Patients were excluded if they were pregnant or physically

handicapped or if there was any associated medical prob-

lem (e.g., inflammatory rheumatic diseases, other painful

conditions, or known malignancy).

Making FIQ-P

Translation

The original FIQ [14] was translated from English into

Persian by a bilingual linguist. Then, a panel composed of

two rheumatologists, two general practitioners, and an

experienced specialist in designing questionnaires, reached

a consensus about the terms used in the translated text; so

the initial Persian draft of the FIQ was generated. After

that, we had our initial Persian version back-translated into

English by another bilingual linguist who had no previous

knowledge about the questionnaire.

Adaptation

We administered the initial Persian version to a pilot group

of patients with FM to evaluate the areas of potential

comprehension difficulty and assess the need for cultural

adaptation. After making some modifications according to

the results of the pilot study, we obtained a definitive

Persian version of FIQ (FIQ-P) (see ‘‘Appendix’’). This

version again back-translated into English by another

blinded bilingual linguist, and then, it was evaluated in

term of concordance with the original FIQ.

Study questionnaires and measures

FIQ [14]

The FIQ is composed of 10 items. The first item contains

questions related to daily activities, each are rated in a 4-point

Likert type scale from 0 (always able to do) to 3 (never able to

do). The scores are summed and divided by the number of

rated items to yield a score between 0 and 3 for physical

functioning. Items 2 and 3 are about the number of days the

patient felt well (0–7) or was unable to work (including

housework) because of FM symptoms over the last week

(0–7), respectively. Item 2 is scored inversely, so that a higher

score means greater impairment (i.e., 0 days = 7, 1 day = 6,

2 days = 5, etc.); but item 3 is scored directly (i.e.,

0 days = 0, 1 day = 1, 2 days = 2, etc.). Item 4 through 10

contain 100 mm visual analogue scales on which the patients

rate their pain, fatigue, stiffness, morning tiredness, difficulty

to do job, anxiety, and depression. After initial scoring is

obtained, each of the resulting scores is standardized on a

0–10 scale, with higher scores indicating more impairment.

SF-36 questionnaire [13]

As a health-related quality of life questionnaire, the SF-36

consists of 36 questions categorized in 8 domains: general

health, mental health, role physical, role emotional, phys-

ical function, social function, bodily pain, and vitality.

Each domain may reach a standardized score between 0

and 100, with higher scores indicating better status. It also

contains one more question about change in health during

the past year, rated in a Likert format scale. In this study,

we used the validated Persian version of the SF-36 [28].

We hypothesized that individuals with higher SF-36 score

would have lower levels of fibromyalgia impairment and

lower FIQ scores.

Beck Depression Inventory (BDI) [29]

This is a self-reported questionnaire that measures patient’s

level of depression. The obtained score ranges from 0 to

63. We used the Persian version of the BDI validated

elsewhere [30]. Individuals with higher BDI score were

hypothesized to take higher FIQ score owing to more

impairment by fibromyalgia.

182 Rheumatol Int (2014) 34:181–189

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Tender point examination

An expert rheumatologist (AB) performed a dolorimetry

examination on each patient. Any of the 18 standard body

points, defined by the ACR 1990 criteria [27], were

examined by a dolorimeter with gradual increasing the

pressure at rate of about 1 kg/cm2/s. If pain was elicited

with pressures less than 4 kg/cm2, the point was considered

to be tender.

Study protocol

All eligible patients were received sufficient information

about objectives of the study, and those who completed a

written consent form were recruited.

At first visit, demographic data were obtained from all

enrolled subjects; they completed the FIQ-P as well as

other study questionnaires and underwent dolorimetry

examination. After 7 days, patients came back to the same

clinic for a second visit and completed another FIQ-P as

the retest measure. During the week, no new therapeutic

intervention was introduced.

Statistical analysis

Data were analyzed using the software SPSS version 20.0.

Descriptive statistics were calculated, and results were

expressed, where applicable, as proportions and mean with

standard deviation (SD). The internal consistency for items of

the FIQ-P was measured with Cronbach’s alpha coefficient.

The construct validity was computed by the Spearman’s

correlation coefficient (r) between the FIQ-P and the other

questionnaires. Test–retest reliability was calculated again by

using the Spearman’s coefficient. All statistical tests were

two tailed, and statistical significance was set at P \ 0.05.

Results

Demographics

The study sample consisted of 30 patients fulfilling the

ACR 1990 criteria for FM. The mean age (±SD) of par-

ticipants was 40.4 (±9.0) years, all of them were females.

Of the total of 30 enrolled subjects, 21 (70 %) were mar-

ried, 20 (66 %) were housekeeper, and education level of

24 (80 %) was diploma or higher. Table 1 summarizes

demographic characteristics of the study patients.

Results of cultural adaptation

After administering the initial Persian version of FIQ to a

pilot group of FM patients, some issues were noted and we

changed two sub-items of physical functioning for cultural

adaptation:

1. The ninth item, ‘‘Do yard work?’’, was coded by only

34 % of pilot FM patients, because people in Tehran

usually live in apartments; so we changed it to a more

applicable question in the definitive FIQ-P (see ‘‘Appen-

dix’’) which was back-translated as ‘‘Undertake flower

pot arrangements or simple decorative activities?’’.

2. The tenth item, ‘‘Drive a car?’’, was left blank by 83 %,

since the number of Iranian women (especially house-

keepers) who drive cars is less than Western countries.

Instead, using public transportation or transporting

services by women are more common in Iran. Thus, we

replaced the tenth item with another relevant question in

the final FIQ-P (see ‘‘Appendix’’) that was back-

translated as ‘‘Ability to use public transportation?’’.

Analysis of translation of final FIQ-P indicated it is

satisfactory and concordant for most of the questions, and

the translators considered none of the back-translated

questions as vague or doubtful. When comparing the ori-

ginal FIQ and the back-translation of FIQ-P, only two

differences were found, both stem from the cultural adap-

tations in sub-items 9 and 10.

Reliability and internal consistency of the FIQ-P

The mean (±SD) of FIQ-P items at baseline and at the

second visit, as well as results of test–retest analysis is

presented in Table 2. Analysis of reliability indicated

correlation coefficients between the test and retest varying

from 0.50 for work days missed to 0.79 for Job ability and

total FIQ-P items (Table 2). Furthermore, an a coefficient

of 0.80 was obtained for internal consistency of the total

items of the FIQ-P.

Table 1 Demographic characteristics of 30 study females with

fibromyalgia

Age (years)* 40.4 ± 9.0

Marriage status**

Married 21 (70)

Single 3 (10)

Widow 6 (20)

Educations**

Under diploma 6 (20)

Diploma 16 (53.3)

Higher diploma 8 (26.6)

Work status**

Housekeeper 20 (66.6)

Working outdoor 10 (33.3)

* Value is the mean ± SD

** Values are the no. (%)

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Correlations of the FIQ-P items with two other

questionnaires

Correlation coefficients between the FIQ-P items and the

components of the SF-36 questionnaire are shown in

Table 3. In general, the FIQ-P indicated overall correlation

with the BDI and the SF-36 as 0.53 (P \ 0.01) and -0.57

(P \ 0.01), respectively.

The strongest correlation was found between item of

depression from the FIQ-P with item of mental health from

the SF-36 (-0.64, P \ 0.01). Taking the SF-36 into

account, when compared to its other components, items of

physical functioning, bodily pain and general health indi-

cated good correlation with several FIQ-P items.

Discussion

Based on this study, we found the FIQ-P is a valid and

reliable measure, having fair correlation with the BDI and

the SF-36.

The only significant modification to original FIQ was

that of cultural adaptation specific for female population.

Most validation studies for FIQ have been published from

developed countries [18–24]. In many developing coun-

tries, such as Iran, the mode of social responsibilities of

females is rather different. Many women are housewives,

and the outdoor responsibilities are less prominent. As FM

is significantly more frequent in females, any questionnaire

aimed to assess the disease impact is required to include

routine female roles and activities, an issue which high-

lights considering cultural differences of activity of daily

living in this specific gender. When we applied the initial

translated draft of FIQ to a pilot FM group, the items

‘‘Drive a car?’’ and ‘‘Do yard work?’’ were left blank in 83

and 64 % of circumstances, respectively. Similar obser-

vations have also been reported from Turkey; where the

former attributed to the less popularity of driving task

among the women, and the latter to the condition of living

in apartments and lack of private gardens [26]. In fact, the

FIQ had been previously criticized for underestimating

functional impairment through focusing on activities that

may not be routinely performed by patients [31]. Trying to

improve the FIQ-P sensitivity, we chose to substitute that

Table 2 Mean scores and standard deviations at two visits and test–

retest reliability of items of Persian version of Fibromyalgia Impact

Questionnaire (FIQ-P)

FIQ-P item First visit* Second visit* Spearman’s

correlation

coefficient**

Physical function

(0–10 scale)

4.79 (1.90) 4.93 (0.94) 0.70

Days feeling good

(0–7 scale)

2.10 (2.28) 2.47 (2.25) 0.68

Work days missed

(0–7 scale)

4.37 (2.82) 3.87 (2.51) 0.50

Job ability (0–10

scale)

5.90 (2.66) 6.67 (2.29) 0.79

Pain (0–10 scale) 6.83 (2.20) 6.87 (2.37) 0.74

Fatigue (0–10 scale) 7.97 (2.09) 8.03 (1.79) 0.63

Morning tiredness

(0–10 scale)

8.17 (2.05) 7.80 (1.54) 0.72

Stiffness (0–10 scale) 7.20 (2.51) 7.53 (2.46) 0.70

Anxiety (0–10 scale) 6.63 (2.93) 6.33 (2.95) 0.67

Depression (0–10

scale)

5.40 (3.01) 5.60 (2.85) 0.67

Total FIQ-P (0–100

scale)

62.13 (13.82) 62.84 (12.53) 0.79

* Values are the mean (SD)

** All coefficients reached statistical significance for a P value\0.01

Table 3 Non-parametric Spearman’s correlation coefficient between items of Persian version of Fibromyalgia Impact Questionnaire (FIQ-P)

and the Medical Outcome Survey Short Form-36 (SF-36)

Physical

function

Days

feeling good

Work days

missed

Job

ability

Pain Fatigue Morning

tiredness

Stiffness Anxiety Depression

SF-36

Physical functioning -0.50** -0.48** -0.63** -0.53** -0.36** -0.20* -0.47** -0.16* -0.40** -0.41**

Role physical -0.22 0.27 0.31 -0.13 -0.21* -0.19 -0.17 -0.12 -0.31* -0.24

Bodily pain -0.63** -0.52** -0.50* -0.46** -0.53* -0.41** -0.45* -0.29* -0.46** -0.55*

General health -0.33* -0.43** -0.53** -0.36* -0.28* -0.24* -0.45** -0.46** -0.55** -0.43**

Vitality -0.31* -0.20 -0.18 -0.19 -0.57* -0.53 -0.19 -0.08 -0.60* -0.52*

Social functioning -0.12 -0.12 -0.31** -0.25* -0.32** -0.21* -0.45** -0.11 -0.23* -0.44*

Role emotional -0.35* -0.19** -0.10 -0.62** -0.13 -0.31** -0.50* -0.21** -0.03 -0.28*

Mental health -0.39* -0.38* -0.20* -0.29 -0.19** -0.46** -0.38** -0.20* -0.49** -0.64**

* P \ 0.05

** P \ 0.01

184 Rheumatol Int (2014) 34:181–189

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items with ‘‘Ability to use public transportation?’’ and

‘‘Undertake flower pot arrangements or simple decorative

activities?’’, more common social tasks among Iranian

women.

We found FIQ-P as a reliable tool over time, with

overall test–retest reliability of 0.79 when we administered

the questionnaire to sample cases 1 week apart (ranging

from 0.50 for ‘‘work days missed’’ to 0.79 for ‘‘job abil-

ity’’). The reliability of the original FIQ in English had

been ranged from 0.56 on the pain score to 0.95 for

physical function [32]. The internal consistency of the FIQ-

P also proved good with Cronbach a of 0.80 for all items.

Although higher alphas have been reported from developed

countries [18–24], studies from developing eastern coun-

tries found values of 0.80 or less [17, 25, 26]. In the ori-

ginal version of the FIQ, however, the internal consistency

had not been evaluated [32].

We did not recruit men with FM. No study has been

specifically analyzed the validity of FIQ in this sex group.

Taking this limitation into account, we are not able to

extrapolate the results of this validation study to the men.

The setting of our study was in an urban population. Fur-

ther studies are required to validate the questionnaire in

rural setting, where different social tasks are expected.

Finally, we used a minimum number of cases needed for a

validation study. Including more cases is recommended to

improve the power of future studies.

In summary, we introduced the first translated version of

FIQ into Persian language. The FIQ-P showed reliable and

valid performance in our selected FM Iranian patients and

could be of use for future follow-up and outcome studies in

Persian-speaking population.

Conflict of interest None.

Rheumatol Int (2014) 34:181–189 185

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Appendix: Persian version of Fibromyalgia Impact

Questionnaire (FIQ-P)

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