Abstract
Objective:
The study aimed to assess the construct validity of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire in Algerian patients with systemic sclerosis.
Methods:
Consecutive Algerian patients who fulfilled the American College of Rheumatology/European League Against Rheumatism criteria for systemic sclerosis were included. In addition to disease characteristics, global disability and hand disability were assessed using the Arabic Health Assessment Questionnaire and the Arab Hand Function Index, respectively. Construct validity was assessed by convergent and divergent validity (Spearman’s rank correlation coefficient) and factor analysis. The scale reliability was assessed using the Cronbach’s alpha.
Results:
We evaluated 100 systemic sclerosis patients (83 females) of mean ± standard deviation age 46.7 ± 12.3 years, including 59 limited cutaneous systemic sclerosis and 41 diffuse cutaneous systemic sclerosis. Raynaud’s phenomenon was detected in 99 patients and digital ulcers in 25. Gastrointestinal tract involvement and interstitial lung disease were detected in 86/100 (86%) and 46/72 (63.9%) patients, respectively. Anti-topoisomerase I and anti-centromere antibodies were detected in 33/76 (43.4%) and 23/76 (30.3%) patients, respectively. The Arab Hand Function Index had a good construct validity with a total score explaining 61% of the variance of the Arabic Health Assessment Questionnaire which also had a good construct validity. Factor analysis of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire items extracted two factors explaining 64% of the variance for the Arab Hand Function Index and one factor explaining 55% of the variance for the Arabic Health Assessment Questionnaire. The Arab Hand Function Index and the Arabic Health Assessment Questionnaire were reliable questionnaires with a Cronbach’s alpha >0.8.
Conclusion:
In Algerian patients with systemic sclerosis, Arab Hand Function Index and Arabic Health Assessment Questionnaire have a good construct validity and reliability.
Keywords: Systemic sclerosis, hand, outcome measures, Arab Hand Function Index, construct validity, health assessment, disability
Introduction
Systemic sclerosis (SSc) is a rare systemic autoimmune disease characterized by vasculopathy, immune dysregulation, and an accumulation of extracellular matrix leading to generalized fibrosis.1,2 Historically, two forms of SSc were described according to the extent of skin fibrosis. In patients with limited cutaneous SSc (lcSSc), skin fibrosis is restricted to distal extremities (distal to elbows and knees) and face. 3 Conversely, the trunk and proximal extremities are affected in patients with diffuse cutaneous SSc (dcSSc). These skin phenotypes are associated with different visceral complications and autoantibodies. Rapid disease progression, renal crisis, and interstitial lung disease (ILD) are associated with dcSSc, more often in association with topoisomerase I- or RNA polymerase III-specific antibodies. Visceral involvement is less frequent in patients with lcSSc who more often have detectable anti-centromere antibodies (ACA).1,3
SSc is associated with reduced life expectancy and an altered health-related quality of life.4,5 A limited number of scales were developed and applied to SSc to assess disability, including the Health Assessment Questionnaire (HAQ). 6 Hand disability is very frequent in SSc and alters daily living. The Cochin Hand Function Scale (CHFS), originally developed in rheumatoid arthritis (RA), was adapted to SSc and recently modified to capture the impact of digital ulcers (DU) on hand function.7–9 Other scales are available to assess hand and wrist disability and hand mobility.10 –13 These index were mainly developed in Occidental populations and are not well suited for Oriental patients. It led to adapt these scales to evaluate proper disability in these patients. For instance, the HAQ was translated into Arabic Health Assessment Questionnaire (HAQa) and some items were modified. 14 Similarly, modifications were made on the CHFS and led to the Arab Hand Function Index (AHFI).7,15 However, HAQa and AHFI were not validated in a cohort of Arabic SSc patients. Psychiatric symptoms, including anxiety and depression, have been reported as a consequence of disease chronicity in SSc patients and can be assessed by the Hospital Anxiety and Depression scale (HAD). 16
The aim of the study was to assess the relevance of AHFI and HAQa, and to evaluate disability in Arabic SSc patients. To this end, the construct validity of these scales was assessed using their convergent and divergent validity and factor analyses.
Patients and methods
Study design
We performed a cross-sectional study in patients with SSc. Patients were prospectively included between January 2015 and December 2016 during hospitalization or follow-up evaluation in Internal medicine (Setif, Batna, and Constantine), Rheumatology (Batna, Constantine), and Dermatology (Constantine) departments of Algerian University hospitals. After an interview with a physician (N.B.), physical examination was performed and patients were asked to complete self-assessment questionnaires (AHFI, HAQa, and HAD) alone or, if necessary, with the help of their families.
Patients
To be eligible for the study, patients had to fulfill the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 17 criteria for SSc.
Parameters recorded were sex, age at the time of study inclusion, age at first symptoms, disease duration, smoking status, professional exposure (silica, solvents), disease subset (lcSSc or dcSSc), 18 skin sclerosis (assessed by the modified Rodnan skin score), 19 mouth opening (interincisor distance measured in millimeters), Raynaud’s phenomenon (RP), DU, pitting scars, digital necrosis, surgical digital amputation, telangiectasia, systolic pulmonary artery pressure (sPAP) > 35 mm Hg as measured by echocardiography, scleroderma renal crisis (SRC), esophagus and gastrointestinal tract involvement, dyspnea, ILD, arthralgia, arthritis, myalgia, myositis (as assessed by muscle biopsy), calcinosis, immunological characteristics, treatments (calcium channel blockers, bosentan, sildenafil), and history or current physiotherapy.
Global hand and wrist mobility assessment
Global hand and wrist mobility were evaluated using the hand function index (HFI; first nine questions of the Keitel functional index) 13 and Kapandji index.10–12 The HFI score ranges from 4 (best mobility) to 42 (worst mobility), and the Kapandji score varies from 0 (worst mobility) to 100 (best mobility).
Global disability
Global disability was assessed by the HAQa (Supplemental Table 1) that includes 20 items evaluating eight domains: dressing/grooming, arising, eating, walking, hygiene, reach, grip, and common daily activities. For each item, the score is quantified from 0 (no disability) to 3 (maximal disability). 20 We have used the Arabic version of the HAQ (HAQa) that was used to evaluate 184 RA patients from Middle East and Morroco. 14 To adapt it to the Arabic culture, two questions of the HAQ were changed: “Are you able to cut meat with a knife” was changed to “Are you able to cut meat, vegetables and fruit using a knife?” and “Are you able to vacuum or work in the garden?” was changed for “Are you able to pray from the standing position/do chores such as home cleaning?.” 14
Hand disability
Hand disability was assessed using the AHFI (Supplemental Table 2), a self-assessment questionnaire of 10 items concerning three domains (kitchen, dressing, and various daily activities). The total score was obtained by adding the scores from all items (range 0–30). 15 The AHFI is an Arabic version of the CHFS. 7 Significant modifications were made to better suit to Arabic population. The AHFI contains only 10 of the 18 original questions of the CHFS. Eight questions and two domains were deleted, and three questions were replaced by two different ones. For the kitchen domain, the question “Can you hold a bowl?” was deleted; the question “Can you take a plat full of food?” was changed to “Can you take a plat full of food and carry it?”; “Can you cut meat with a knife?,” “Can you prick effectively with a fork?,” and “Can you peel fruit?” were replaced by “Can you cut bread with hands?” and “Can you eat with your hand?.” Toilet domain which included two questions “Can you squeeze a full toothpaste tube?” and “Can you hold your toothbrush effectively?” was deleted. The two questions of desk domain “Can you write a short sentence with a pencil?” and “Can you write a letter with a regular pencil or pen?” were deleted. Each question is scored on a scale from 0 to 3 (0: performed without any difficulty; 1: performed with a little difficulty; 2: performed with a great difficulty; 3: impossible to do) instead of a scale of six choices in the CHFS (0: performed without difficulties; 1: performed with very few difficulties; 2: performed with some difficulties; 3: performed with a lot of difficulties; 4: almost impossible to do; 5: impossible to do). The AHFI has already been validated in a Tunisian RA population, 15 we used it for the first time in patients with SSc.
Anxiety and depression assessments
Anxiety and depression significant symptoms were assessed with the Arabic version of HAD anxiety (HADa) and HAD depression (HADd). 21 This scale has seven questions for anxiety and seven for depression. Each item is scored from 0 to 3 and the total score for each dimension ranges from 0 (no depression, no anxiety) to 21 (maximal depression, maximal anxiety). Scores of 0–7 in subscales are considered normal, 8–10 borderline, and 11–21 clinical caseness. 22 We used it for the first time in patients with SSc.
Statistical analysis
Statistical data analysis involved the use of Systat 22 software (SPSS Inc., Chicago, IL, USA). Qualitative variables were described with numbers and percentages and quantitative variables with mean ± standard deviation (SD) (range). For bivariable analysis, comparisons involved Pearson’s chi-square test for qualitative variables, Student’s t-test for quantitative parametric variables, and Mann–Whitney U test for non-parametric quantitative variables.
For each questionnaire (AHFI, HAQa), construct validity was explored using three different ways. First, convergent validity was assessed by correlating the global scale scores with scores on variables supposedly have converging relationship (assessing similar dimensions or concepts). For this, we hypothesized that HFI and Kapandji have converging relationship with HAQa and AHFI. Second, divergent validity was assessed by correlating the scores of both questionnaires with scores on variables known to assess dimensions or concepts differing from those assessed by the questionnaire tested. For that we hypothesized that HAQa and AHFI scores would correlate less with HADa, HADd, age, and disease duration. The non-parametric Spearman’s rank correlation coefficient (r) was used to evaluate correlation between two quantitative variables. Spearman’s coefficient values were interpreted as excellent relationship (>0.91), good (0.90–0.71), moderate (0.70–0.51), fair (0.50–0.31), and little or none (<0.30). 23 Third, factor analysis was performed using the principal analysis to extract factors for the items of the AHFI and HAQa. Retained factors had eigenvalues > 1. Independent factors were obtained using the varimax algebra rotation method. A p-value less than 0.05 was considered significant.
The reliability or internal consistency for AHFI and HAQa was assessed using Cronbach’s alpha coefficient. A coefficient greater than 0.7 means satisfactory consistency.24–26
Ethical considerations
This study was carried out after the approval of the local ethics committee in compliance with the Helsinki Declaration. Patients gave their verbal consent to participate after being verbally informed of the study protocol.
Results
Demographic and clinical data
Overall, 100 patients with SSc (including 17 males) followed in Algerian East University hospitals were included either during their hospitalization or during follow-up evaluation. All of them are White. Mean ± SD age at the time of evaluation was 46.7 ± 12.3 years, while the mean ± SD age at the onset of the disease was 39.29 ± 12.8 years. Disease duration was 6.5 ± 6.2 years. Notably, 13 patients (13.0%) were professionally exposed to silica and 5 (5.0%) were exposed to solvents. A total of 58 patients had lcSSc (59.0%) and 41 had dcSSc (41.0%). Regarding clinical manifestations, almost all patients had RP (99.0%) with pitting scars in 67.0% of cases and telangiectasia in 51.0% of patients. Gastrointestinal tract involvement and arthralgia were the second and the third most frequent clinical involvement (86.0% and 74.0% respectively). The mean modified Rodnan skin score was 10.1 ± 9.6. Other data regarding clinical manifestations, immunological characteristics, and treatments are summarized in Table 1.
Table 1.
Clinical and immunogical characteristics and treatments in 100 Algerian patients with SSc with or without DU.
| Parameters | All patients (n = 100) |
DU (n = 25) |
No DU (n = 75) |
p |
|---|---|---|---|---|
| Epidemiological characteristics | ||||
| Female sex | 83 (83) | 21 (84) | 62 (82.7) | 0.88 |
| Age at evaluation (years), M ± SD | 46.67 ± 12.30 | 48.56 ± 12.30 | 46.04 ± 12.32 | 0.97 |
| Age at the onset of SSc (years), M ± SD | 39.39 ± 12.80 | 41.04 ± 11.59 | 38.84 ± 13.21 | 0.42 |
| SSc disease duration (years), M ± SD | 6.54 ± 6.23 | 7.82 ± 5.55 | 6.29 ± 6.46 | 0.17 |
| Exposure | ||||
| Current smoker | 2 (2) | 0 (0) | 2 (2.7) | 0.61 |
| Professional silica exposure | 13 (13) | 4 (16) | 9 (12) | |
| Professional solvent exposure | 5 (5) | 1 (4) | 4 (5) | |
| Disease form | ||||
| Limited cutaneous SSc | 59 (59) | 6 (24.0) | 53 (70.7) | <0.0001 |
| Diffuse cutaneous SSc | 41 (41) | 19 (76) | 22 (29.3) | |
| Clinical manifestations | ||||
| Modified Rodnan skin score, M ± SD | 10.06 ± 9.60 (0–40) | 16.72 ± 11.23 | 7.69 ± 7.73 | <0.0001 |
| Interincisor distance (mm), M ± SD | 33.70 ± 8.68 | 28.80 ± 9.47 | 35.18 ± 7.91 | 0.97 |
| Raynaud’s phenomenon | 99 (99) | 25 (100) | 74/ (99) | 0.56 |
| Pitting scars | 67 (67) | 22 (88) | 45 (60) | 0.01 |
| Digital necrosis | 8 (8) | 7 (28) | 1 (1.33) | <0.001 |
| Surgical digital amputation | 4 (4) | 2 (8) | 2 (2.66) | 0.42 |
| Telangiectasia | 51 (51) | 19 (76) | 32 (42.7) | <0.01 |
| sPAP > 35 mmHg | 26/74 (39.39) | 12/20 (60) | 14/46 (30.43) | 0.01 |
| Scleroderma renal crisis | 1 (1) | 0 (0) | 1 (1.8) | |
| Gastrointestinal tract involvement | 86 (86) | 24 (96) | 62 (82.7) | 0.10 |
| Esophagus involvement | 80 (80) | 23 (92) | 57 (76) | 0.83 |
| Dyspnea | 55 (55) | 16 (64) | 39 (52) | 0.357 |
| Interstitial lung disease | 46/72 (63.88) | 11/18 (61.11) | 35/54 (64.81) | 0.96 |
| Arthralgia | 74 (74) | 20 (80) | 54 (72) | 0.43 |
| Arthritis | 7 (7) | 2 (8) | 5 (6.7) | 0.82 |
| Myalgia | 32 (32) | 8 (32) | 24 (32) | |
| Myositis | 6 (6) | 0 (0) | 6 (8) | 0.14 |
| Calcinosis | 14 (14) | 9 (36) | 5 (6.7) | <0.0001 |
| Immunological characteristics | ||||
| Anti-centromere abs | 23/76 (30.26) | 5/18 (27.78) | 18/58 (31.03) | 0.51 |
| Anti-topoisomerase 1 abs | 33/76 (43.42) | 10/18 (55.55) | 23/58 (39.66) | |
| Treatments | ||||
| Calcium-channel blockers | 86 (86) | 20 (80) | 66(88) | 0.32 |
| Bosentan | 10 (10) | 7 (28) | 3 (4) | 0.001 |
| Sildenafil | 8 (8) | 4 (16) | 4 (5.3) | 0.09 |
| History of physiotherapy | 15 (15) | 5 (20) | 10 (13.3) | 0.42 |
| Current physiotherapy | 8 (8) | 2 (8) | 6 (8) | 1.00 |
Abs: antibodies; DU: digital ulcer; n: number; sPAP: systolic pulmonary artery pressure; SD: standard deviation; SSc: systemic sclerosis.
Values are the number (percentage) unless otherwise indicated. Pearson’s chi-square test was used for qualitative variables; unpaired t-tests and Mann–Whitney U test were performed for quantitative variables.
Comparison between patients according to the occurrence of DU
Patients were then divided into two groups according to the presence or not of DU, which concerned 25 patients (25.0%) of the cohort. There were significant differences between the two groups regarding the form of the disease (59 lcSSc vs 41 dcSSc, p < 0.0001), the modified Rodnan skin score (16.7 ± 11.2 vs 7.7 ± 7.7, p < 0.0001), the occurrence of pitting scars (88.0% vs 60.0%, p = 0.010), digital necrosis (7.0 vs 1.0% p < 0.001), telangiectasia (76.0% vs 42.7%, p = 0.004), and calcinosis (36.0% vs 6.7%, p < 0.0001) (Table 1). A sPAP > 35 mmHg was more frequent in patients with DU than those without DU (p < 0.05, Table 1). Finally, bosentan was used more in DU group than in non-DU one (28.0% vs 4.0%, p = 0.001).
Outcome measure scores
Patients’ hand global mobility was reduced in the presence of DU regarding HFI (30.92 vs 16.13, p < 0.0001), Kapandji (68.16 vs 85.72, p < 0.0001), and AHFI (9.96 vs 3.61, p < 0.0001) scores. Global disability was assessed by the HAQa score that was increased in the presence of DU (1.45 vs 0.72, p < 0.001). There was a higher depression score compared with anxiety score (9.30 vs 8.98), without significant difference according to the occurrence of DU (Table 2).
Table 2.
Outcome measure scores in 100 Algerian patients with SSc according to the presence or not of DU*.
| Scores | All patients (n = 100) |
DU (n = 25) |
No DU (n = 75) |
p |
|---|---|---|---|---|
| HFI (range 4–42) | 19.83 ± 13.59 (4–42) | 30.92 ± 11.10 (7–42) | 16.13 ± 12.32 (4–42) | <0.0001 |
| Kapandji (range 0–100) | 81.33 ± 18.37 (11–100) | 68.16 ± 22.34 (11–100) | 85.72 ± 14.55 (46–100) | <0.0001 |
| AHFI (range 0–30) | 5.20 ± 6.15 (0–29) | 9.96 ± 7.17 (0–29) | 3.61 ± 4.86 (0–27) | <0.0001 |
| HAQa (range 0–3) | 1.02 ± 0.78 (0–3) | 1.53 ± 0.76 (0.13–3) | 0.86 ± 0.71 (0–2.50) | <0.0001 |
| Anxiety (HADa) (range 0–21) | 8.98 ± 4.54 (0–19) | 10.80 ± 3.91 (3–19) | 8.37 ± 4.60 (0–19) | 0.12 |
| Depression (HADd) (range 0–21) | 9.30 ± 4.67 (0–20) | 10.48 ± 3.92 (4–19) | 8.91 ± 4.86 (0–20) | 0.11 |
AHFI: Arab Hand Function Index; DU: digital ulcers; HADa: Hospital Anxiety and Depression scale for anxiety; HADd: Hospital Anxiety and Depression scale for depression; HAQa: Arabic Health Assessment Questionnaire; HFI: Hand Function Index (first nine items of the Keitel index); n: number; SSc: systemic sclerosis.
Values are the mean ± standard deviation (range). Unpaired t-tests and Mann–Whitney U test were performed.
Then, a similar analysis was performed according to the disease form (Table 3). Patients’ hand global mobility and disability differed significantly between the two groups (dcSSc and lcSSc) based on HFI, Kapandji, and AHFI scores (p < 0.0001). The global disability, assessed by HAQa, was also significantly different according to the disease form (p < 0.0001). For each score studied, the dcSSc group had the most severe disability. There was no difference between groups regarding anxiety and depression (p = 0.07 and 0.31, respectively). Finally, disease duration was significantly different with the higher mean ± SD for dcSSc patients (8.4 years ± 7.7) while the age at evaluation was similar between groups (p = 0.51).
Table 3.
Outcome measure scores in 100 Algerian patients with SSc* according to the disease form.
| Scores | dcSSc group (n = 41) | lcSSc group (n = 59) | p |
|---|---|---|---|
| HFI (range 4–42) | 28.66 ± 11.53 (4–43) | 13.70 ± 11.41 (4–38) | <0.0001 |
| Kapandji (range 0–100) | 71.61 ± 19.72 (11–100) | 88.09 ± 13.96 (48–100) | <0.0001 |
| AHFI (range 0–30) | 8.12 ± 6.79 (0–29) | 3.17 ± 4.73 (0–27) | <0.0001 |
| HAQa (range 0–3) | 1.45 ± 0.76 (0–3) | 0.72 ± 0.64 (0–2.38) | <0.0001 |
| Anxiety (HADa) (range 0–21) | 9.95 ± 4.49 (1–19) | 8.31 ± 4.49 (0–19) | 0.07 |
| Depression (HADd) (range 0–21) | 9.88 ± 4.43 (0–19) | 8.90 ± 4.83 (0–20) | 0.31 |
| Disease duration | 8.36 ± 7.68 | 5.27 ± 4.65 | 0.04 |
| Age at evaluation | 47.66 ± 12.28 | 45.98 ± 12.37 | 0.51 |
AHFI: Arab Hand Function Index; dcSSc: diffuse cutaneous SSc; HADa: Hospital Anxiety and Depression scale for anxiety; HADd: Hospital Anxiety and Depression scale for depression; HAQa: Arabic Health Assessment Questionnaire; HFI: Hand Function Index (first nine items of the Keitel index); lcSSc: limited cutaneous SSc; n: number; SSc: systemic sclerosis.
Values are the mean ± SD (range) unless otherwise indicated.
Construct validity of the AHFI
The AHFI had a moderate convergent validity with global disability assessed by the HAQa (r = 0.61, p < 0.001) and the HFI (r = 0.55, p < 0.001), fair correlation with the Kapandji index (r = −0.48: inverse correlation, p < 0.001), depression (HADd; r = 0.45, p < 0.001), and anxiety (HADa; r = 0.42, p < 0.001), and no correlation with the disease duration and age (Table 4). Factor analysis extracted two factors with eigenvalues > 1 that accounted for 64.45% of the total variance (Supplemental Table 3). The first factor represents activities requiring grip and pinch strength, and the second factor represents activities requiring force and pinch dexterity (Supplemental Table 4). The loading of each question after varimax rotation on the two factors is shown in Supplemental Table 4.
Table 4.
Convergent and divergent validities of the AHFI and HAQa for patients with SSc (correlation with other variables)*.
| Scales | Spearman’s correlation coefficient | p |
|---|---|---|
| AHFI | ||
| Convergent validity | ||
| HAQa | 0.61 | <0.001 |
| HFI | 0.55 | <0.001 |
| Kapandji | −0.48 | <0.001 |
| Divergent validity | ||
| Depression (HADd) | 0.45 | <0.001 |
| Anxiety (HADa) | 0.42 | <0.001 |
| Disease duration | 0.29 | 0.003 |
| Age | 0.19 | 0.06 |
| HAQa | ||
| Convergent validity | ||
| AHFI | 0.61 | <0.001 |
| HFI Kapandji |
0.50 −0.46 |
<0.001 <0.001 |
| Divergent validity | ||
| Anxiety (HADa) Depression (HADd) |
0.57 0.48 |
<0.001 <0.001 |
| Disease duration | 0.11 | 0.260 |
| Age | 0.28 | 0.005 |
AHFI: Arab Hand Function Index; HADa: Hospital Anxiety and Depression scale for anxiety, HADd: Hospital Anxiety and Depression scale for depression; HAQa: Arabic Health Assessment Questionnaire; HFI: Hand Function Index.
Construct validity of the HAQa
The HAQa had a moderate correlation with hand disability (r = 0.61), anxiety (r = 0.57), a fair correlation with the HFI (r = 0.50), depression (r = 0.48), and Kapandji index (r = −0.46), and a little correlation with the age and the disease duration (Table 4).
The factor analysis of the HAQa extracted one factor with eigenvalue > 1 that accounted for 54.95% of the total variance (Supplemental Table 3). The loading of each question after varimax rotation on the main factor is shown in Supplemental Table 4.
Reliability of the AHFI
We studied the reliability of the AHFI by calculating the Cronbach’s alpha coefficient of the 10 items of the scale. The result was 0.894 (Supplemental Table 5). This led to the conclusion that the AHFI is a reliable questionnaire to assess hand disability in Arabic patients.
Reliability of the HAQa
The reliability study of the HAQa calculated by the Cronbach’s alpha coefficient of the eight domains of the HAQa was 0.880 (Supplemental Table 5) and therefore, greater than 0.7, which yields good internal consistency to each of its components.
Discussion
Our study assessed for the first time the validity of self-questionnaires to capture hand and global in SSc Algerian patients. We took advantage of a cohort of 100 patients with SSc which was rather similar to another Algerian study of 144 subjects. Indeed, our patients had shorter disease duration (6 vs 12 years), were evaluated at the same age (46 years), had less DU (25% vs 63.2%), and ILD (63.88% vs 70.1%), higher frequency of arthralgia (75% vs 63.2%), lower frequency of arthritis (7.0% vs 40.3%), and almost the same proportion of telangiectasia (51% vs 57.6%), digital necrosis (8.0% vs 9.0%), and calcinosis (14% vs 18.1%) 27
Clinical characteristics of patients seem to have similarities with the East Asian patient group of the Canadian multiethnic SSc study that included mainly White descendants (74), Afro-Caribbean (58), South Asian (70), Hispanic (30), Arab (9), First Nations (7), and Persian (7). 28 In fact, the prevalence of diffuse subtype (41% vs 48%), calcinosis (14% vs 9%), DU (25% vs 26%), telangiectasia (51% vs 57%), and SRC (1% vs 1%) in our cohort were similar to the East Asian group. Nevertheless, in the Arabic group of the Canadian study, there were more calcinosis (33% vs 14%) and telangiectasia (67% vs 51%), less ILD (33% vs 63.88%) and relatively identical DU frequency (22% vs 25%) than reported with our patients.
When compared to the Spanish patients with SSc, lower prevalence of vascular involvement was noted in our patients regarding DU (25% vs 41%) and telangiectasia (51% vs 60%). 29 The Spanish study reported comparable results to ours considering the proportion of calcinosis (19% vs 14%) and SRC (4.2% vs 1%). Whereas, higher frequency of esophagus involvement (80% vs 61%) and ILD (63.88% vs 43%) was noticed in the current study than in the Spanish cohort. 29
The results point out that AHFI, an Arab and adapted version of the CHFS, had a good construct validity in patients with SSc. The AHFI global score contributes for 61% of the global disability assessed by the Arab version of the HAQ, highlighting one more time the need to specifically assess hand functional capacity when evaluating the disability caused by the disease. 8
The mean score of the AHFI of all group studied was similar to the one of the Tunisian RA population (5.20 vs 6.1) for whom it was developed and validated for the first time. The AHFI scores are significantly different depending on the SSc subtypes and the occurrence of the DU. Put differently, when the disease is severe or when the DU are present, the disability of the hand is even more important (Tables 2 and 3).
Taking into account the previous studies, the construct validity of convergent and divergent results has shown a significant correlation between CHFS, HAQ, and hand mobility scores in a group of 40 and 50 patients with SSc.8,30 It leads to the conclusion that CHFS and AHFI have a good construct validity in SSc and RA.8,15,30 Unexpectedly, HAQa and AHFI correlated with anxiety and depression in Algerian SSc patients which Rannou et al. could not find. 8
In addition, the factor analysis has easily highlighted two characterized factors as founded in Guermazi’s study for RA 15 except for Item 1 (Can you cut bread with your hands ?) and Item 3 (Can you pour liquid from a pitcher into a glass?), one requiring pinch strength and force, the other requiring dexterity. These differences are not surprising because the clinical involvement at baseline is different when we deal with different diseases, such as RA and SSc, because joint, tendons, and skin involvements are not similar. 8 In SSc, skin fibrosis, hand retraction, and vascular damage alter hand mobility and lead to hand disability. However, the correlation of Items 3, 4, 5, 9, and 10 to both factors extracted for CHFS used by Rannou with patients having SSc 8 was not the same as those extracted in our study. We supposed that it is due to the changes made to the scale to suit the Arabic culture (Items 1 and 3).
Factor analysis of the AHFI extracted two factors that accounted for 64% of the total variance in the current study, 73% on patients with RA, 15 and 72% when using CHFS with French SSc patients. 8
The HAQ has been largely used in SSc to assess the global disability,6,31,32 we used an Arab version. We did not use the aggregate score of the scleroderma HAQ (sHAQ) because there is no Arabic version and no data are suggesting a superiority of the aggregate sHAQ score over the HAQ score to assess disability.8,31,33
In the current work, the factor analysis supports a stronger factorial structure of the HAQa because the scale is a unique dimensional character. For HAQa, factor analysis extracted one factor that accounted for 55% of the total variance, less than when it was used with RA (72%), 15 highlighting the difference impact of both diseases on global disability. Other studies are needed to confirm these ascertainments.
We notice that outcome measure scores of hand mobility and depression observed in our study were higher than those reported in a previous study. 8
We recruited 100 patients for this study, which is the minimum necessary to perform principal component analysis.34,35 One limitation of our study may be the procedure applied to recruit patients. Because all patients are from the Algerian East, they may not be representative of the entire Algerian SSc population. It is necessary to note the difficulties of realizing some exams that are sometimes not available in Algerian University hospitals. This is the case for plethysmography, high-resolution computed tomography of the chest, cardiac ultrasound, and immunological tests, which are very expensive to perform in the private sector. In another limitation, we could not evaluate the quality of life in Algerian SSc patients because there is only a Tunisian Arabic dialectal version of the 36-item Short Form Health Survey (SF-36). 36 It will be interesting to suit it to Algerian dialectal or literary Arabic to use it within Arabic population.
Concerning our results, principal component analysis can be applied to HAQa (one factor, high loading of each item in this factor) and AHFI (for each item, high loading in one factor and low loading in the other factor).
The HAD scale has already been used in SSc 37 and has been recently validated on Swiss SSc patients. 16 The HAD scale Arabic version has been already validated in Saudi patients. In this study, we used it for the first time on Arabic patients with SSc.
In conclusion, the AHFI and the Arab HAQ are reliable and valid instruments that can be self-administered by patients with Arabian SSc to assess their hand and global disability, respectively. They suit Algerian people and should be used in other Arab populations. Hand functional disability is the major component of global disability and therefore should be systematically evaluated.
Supplemental Material
Supplemental material, sj-pdf-1-jso-10.1177_23971983241231082 for Assessing hand and global disability in a cohort of Algerian patients with systemic sclerosis: Construct validities of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire by Nouria Benmostefa, Rachid Malek, Marie Robert, Benjamin Chaigne, Samy Slimani, Samir Rouabhia, Daoud Roula, Mallem Djamel and Luc Mouthon in Journal of Scleroderma and Related Disorders
Acknowledgments
The authors thank patients from the departments of Internal Medicine (Setif, Batna and Constantine), Rheumatology (Batna and Constantine), and Dermatology (Constantine) for their participation in the study. They also thank Pr A Abdessemed, Pr S Ali-Guechi, Dr A Ammar, Dr I Bencharif, Dr D Bendjenna, Dr B Benlahcene, K Bouaiche, Dr L Bouakkaz, Dr M Bouchenak, Dr A Bouchiha, Dr A Boularouk, Dr FZ Boussekine, Pr R Chermat, Dr N Derdouba, Pr F Djabi, Dr C Djabri, Dr S Fahloul, Pr F Kaddour, Dr FZ Kahoul, Dr N Kerouaz, Dr W Keffi, Dr F Keskes, Dr H Khebbat, Dr H Khellaf, Pr S Laouamri, Pr S Lemai, Pr T Mansoul, Pr FZ Mekideche, Dr AM Nechadi, Pr C Nguyen, Pr S Poiraudeau, Dr A Sai, Dr N Tebbi, Dr F Tonto, Pr AR Touabti, Dr Y Zemouli, Dr N Zighmi, and every personnel who participated in the data collection.
Footnotes
Author contributions: N.B., R.M., S.R., S.S., and D.R. have full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. N.B., R.M., B.C., and L.M. contributed to the study design. N.B., R.M., S.R., S.S., M.D., and D.R. involved in acquisition of data. N.B., B.C., M.R., R.M., and L.M. participated in analysis and interpretation of data. N.B., M.R., B.C., R.M., and L.M. involved in article preparation. N.B., R.M., and L.M. performed statistical analysis.
Data availability statement: The datasets generated during or analyzed during the current study are available from the corresponding author on reasonable request.
Assessing hand and global disability in a cohort of Algerian patients with systemic sclerosis (SSc): construct validities of the Arab Hand Function Index (AHFI) and the Arabic Health Assessment Questionnaire (HAQa)
The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.B. received fees from El Kendi. L.M. has received grants and consultancy fees from Boehringer Ingelheim. R.M., M.R., B.C., S.S., S.R., M.D., and D.R. declare that there are no competing interests.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
ORCID iD: Nouria Benmostefa 
https://orcid.org/0000-0002-5787-4986
The statement: The Editor/ Editorial Board Member of JSRD is an author of this article; therefore, the peer review process was managed by alternative members of the Board and the submitting Editor/Board member had no involvement in the decision-making process.
Supplemental material: Supplemental material for this article is available online.
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Supplementary Materials
Supplemental material, sj-pdf-1-jso-10.1177_23971983241231082 for Assessing hand and global disability in a cohort of Algerian patients with systemic sclerosis: Construct validities of the Arab Hand Function Index and the Arabic Health Assessment Questionnaire by Nouria Benmostefa, Rachid Malek, Marie Robert, Benjamin Chaigne, Samy Slimani, Samir Rouabhia, Daoud Roula, Mallem Djamel and Luc Mouthon in Journal of Scleroderma and Related Disorders