Rheumatology International

, Volume 32, Issue 2, pp 357–360

Relationship between diagnosis delay and disease features in Moroccan patients with ankylosing spondylitis

Authors

    • Department of Rheumatology (Pr N. Hajjaj-Hassouni), El Ayachi HospitalUniversity Hospital of Rabat-Sale
  • Bouchra Amine
    • Department of Rheumatology (Pr N. Hajjaj-Hassouni), El Ayachi HospitalUniversity Hospital of Rabat-Sale
  • Assia Laatiris
    • Department of Rheumatology (Pr N. Hajjaj-Hassouni), El Ayachi HospitalUniversity Hospital of Rabat-Sale
  • Rachida Bensabbah
    • Department of Rheumatology (Pr N. Hajjaj-Hassouni), El Ayachi HospitalUniversity Hospital of Rabat-Sale
  • Najia Hajjaj-Hassouni
    • Department of Rheumatology (Pr N. Hajjaj-Hassouni), El Ayachi HospitalUniversity Hospital of Rabat-Sale
Original Article

DOI: 10.1007/s00296-010-1635-7

Cite this article as:
Ibn Yacoub, Y., Amine, B., Laatiris, A. et al. Rheumatol Int (2012) 32: 357. doi:10.1007/s00296-010-1635-7

Abstract

We aimed to evaluate diagnosis delay and its impact on disease in terms of activity, functional disability, and radiographic damage in Moroccan patients with ankylosing spondylitis (AS). We recruited 100 Moroccan patients who fulfilled New York Classification criteria for AS. Diagnosis delay was defined as the interval between the first symptom of AS and the moment of a correct diagnosis. Disease activity was evaluated by the bath ankylosing spondylitis disease activity index (BASDAI), functional status by the bath ankylosing spondylitis functional index (BASFI), and radiographic damage by the bath ankylosing spondylitis radiologic index (BASRI). Measurements of spinal mobility were assessed. The average age at disease onset was 28.56 ± 10.9 years. Of the patients, 16% had juvenile-onset AS. Disease duration was 9.5 ± 6.8 years, and the average of diagnosis delay was 4.12 ± 3.99 years. There were no differences in diagnosis delay according to the age at onset, educational level, or the presence of extra-articular involvement. Our patients had altered functional ability. Patients with late diagnosis (>5 years) had statistically significant higher structural damage (BASRI) and severe limited spinal mobility. There was no correlation between diagnosis delay and the activity of disease. Few studies focused on diagnostic delay and its impact in patients with AS. It is necessary in our context to establish an early diagnosis taking into account the high frequency of severe functional disability in Moroccan AS.

Keywords

Diagnosis delayAnkylosing spondylitisFunctionActivityMobilityRadiographic damage

Introduction

Ankylosing spondylitis (AS) is a chronic inflammatory progressive disease that has the longest diagnostic delay among rheumatic diseases [1]. The presence of inflammatory back pain during the clinically unrecognized “pre-spondylitic” phase, which on average could take 5–10 years or more, is accompanied by progressive structural damage that may take place quietly [2]. Early diagnosis and intervention in patients with AS are important because it may reduce destructions of the disease [1]. Taking into account the advent of new and effective treatments, such as anti tumor necrosis agents, it is possible to say that early diagnosis is now even more judicious [3, 4]. Recent studies show a high response to anti-TNF agents in patients with shorter disease duration [5]. Despite this, the diagnosis of AS is often missed and markedly delayed. To our knowledge, no Maghrebean or Arabic studies have focused on diagnostic delay and its impact in patients with AS [1, 6]. Anterior studies suggest a severe pattern of AS in the Maghreb and North Africa explained by low socio-economic status and delayed therapeutic interventions [7].

In this cross-sectional study, we aimed to evaluate diagnosis delay and its impact on disease outcome in terms of activity, functional disability, and radiographic damage in Moroccan patients with ankylosing spondylitis.

Patients and methods

Patients

This cross-sectional study was carried out at the Department of Rheumatology of El Ayachi Hospital in the university hospital of Rabat-Sale in Morocco between December 2008 and July 2009. Patients came to our center from all over the country (urban and rural areas). One hundred consecutively diagnosed patients with AS according to modified New York Classification criteria were included [8]. Our study was approved by local medical ethics committee. Informed consent was obtained from all patients.

Following data were collected: age, gender, educational level (subdivided into three groups: illiterate, primary education, and secondary education or more), disease duration (years), morning stiffness, night pain, and peripheral and axial pain (on visual analog scale (VAS) from 0 (very well) to 10 (very bad)). All parameters were collected at the same time of the day and by a single investigator.

Age at onset of symptoms and age at first diagnosis of AS were assessed. Age at the onset was defined as the time when axial, peripheral, or enthesitis symptoms have appeared for the first time (subdivided into two groups: juvenile-onset ankylosing spondylitis (≤16 years old) and adult-onset ankylosing spondylitis (>16 years old)). Diagnosis delay was defined as the interval between the first symptom of AS and the moment of a correct diagnosis.

Functional status was assessed by bath ankylosing spondylitis functional index (BASFI) from 0 to 10 (0 = performed without difficulty and 100 = impossible to perform). The activity of disease was assessed by the bath ankylosing spondylitis disease activity index (BASDAI score: from 0 = no activity to 10 = maximum activity). These indexes were translated into Moroccan dialect and validated [9]. Occiput-wall distance, chest expansion was measured and Schober’s test was used to measure spinal mobility [10].

Radiographs of sacroiliac joints, lumbar spine, and cervical spine were assessed by using the bath ankylosing spondylitis radiologic index (BASRI) with a possible range of 0–12 [11]. Fatigue was evaluated using the first item of the BASDAI questionnaire “how could you describe the overall level of fatigue/tiredness you have?”. The answer was recorded using a 0–100 VAS scale (0 = no fatigue and 100 = worst fatigue imaginable) [12].

Biologic assessment included erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP).

Statistical analysis

All statistical analyses were performed using Statistical Package for the Social Sciences for Windows, version 13.0 (SPSS, Inc., Chicago; IL, USA). P < 0.05 was considered significant. Data are presented, for continuous variables, as means and standard deviation and for categorical variables, as frequencies and percentages. Differences between the three groups of educational level were examined by analysis of variance (ANOVA). Differences according to the age of onset, professional status, and the presence or not of extra-articular manifestations of disease were assessed by t test for continuous variables. Correlations were performed with Pearson correlation coefficient.

Results

One hundred patients with AS were recruited. There were 67 mens (67%), age (mean ± SD) 38 ± 13 years, disease duration 9.5 ± 6.8 years. Patient’s characteristics and disease-related variables are summarized in Table 1. Average age of the patients at disease onset was 28.56 ± 10.9 years, average age at diagnosis was 32.68 ± 11.56, and the average of diagnosis delay was 4.12 ± 3.99 years. Before consulting our medical center, all patients had visited one or more physicians and 90% had a wrong alternative diagnosis (mechanical back pain, herniated disk; non specific arthralgia or fibromyalgia). Only 10% of our patients had a correct diagnosis before coming to our unit. When a correct diagnosis was established, it was by a rheumatologist (91%) or internist (9%). Mean value of BASDAI score was 47 ± 16 (range 10–80), indicating moderate disease activity. Mean BASFI value was 54 ± 19 (range 12–90), indicating important functional impairment. Mean value of BASRI score was 7 ± 3.0 (2–15). Of our patients, 17% had extra-articular manifestations with most of the patients having uveitis (40%) and pulmonary involvement (10%). Of our patients, 6% received anti-TNF agents, 89% were treated with DMARD’s (disease modifying anti rheumatic drugs), and 5% were treated with only non-steroidal anti-inflammatory drugs. There was no difference in diagnosis delay between patients with and without extra-articular involvement (P = 0.295). There was no statistically significant difference in diagnosis delay between patients with juvenile-onset and those with adult-onset disease (P = 0.709). Also, educational level and professional status had no impact on diagnosis delay (P > 0.2). According to diagnosis delay, our patients were divided into two groups: diagnosis delay less than 5 years (63%) (Early diagnosis) and diagnosis delay more than 5 years (37%) (Late diagnosis). There were statistically significant differences between the two groups according to average mobility measurements, BASFI, and BASRI. Figure 1 summarizes those results.
Table 1

Characteristics of patients with ankylosing spondylitis (n = 100)

 

Mean ± SD or n (%)

Range

Male sex

67 (67%)

 

Age at onset

 Juvenile onset

16%

 

 Adult onset

84%

 

Age (years)

38 ± 13

18–72

Age at diagnosis (years)

32.68 ± 11.56

12–64.5

Diagnosis delay (years)

4.12 ± 3.99

0.5–21

Disease duration (years)

9.2 ± 6.8

1–32

VAS axial (0–10)

47.4 ± 18.3

10–90

VAS peripheral (0–10)

35 ± 28.1

0–90

Morning stiffness (minutes)

50.6 ± 43.7

0–240

BASDAI

47 ± 16

10–80

BASFI

53.4 ± 18.6

12–90

Occiput-wall (cm)

4 ± 6.2

0–32

Chest expansion (cm)

3.4 ± 1.2

0.5–6

Schober index (cm)

2.7 ± 1.2

0.5–5

BASRI

6.7 ± 3.1

2–15

ESR (mm)

33.3 ± 20

2–120

CRP (mg/l)

16.4 ± 15.9

1–83

BASDAI fatigue

39.8 ± 16.26

10–80

NSAI non-steroidal anti-inflammatory drugs, VAS visual analog scale, BASDAI bath ankylosing spondylitis disease activity index, BASFI bath ankylosing spondylitis functional index, BASRI bath ankylosing spondylitis radiologic index, ESR erythrocyte sedimentation rate, CRP C-reactive protein

https://static-content.springer.com/image/art%3A10.1007%2Fs00296-010-1635-7/MediaObjects/296_2010_1635_Fig1_HTML.gif
Fig. 1

Disease-related variables indices in early and late diagnosis (Student’s t test). †Statistically significant P < 0.05

Correlations between diagnosis delay and disease-related parameters of activity and severity showed that the increase in diagnosis delay had a good statistically significant correlations with severe mobility limitation of the three segments of the spine, severe functional disability (higher scores of BASFI), and an important radiologic damage (higher scores of BASRI). Results are shown in Table 2. There was no correlation between diagnosis delay and activity of disease (BASDAI) or biologic markers (P > 0.05).
Table 2

Correlations between diagnosis delay and disease-related parameters

 

Pearson’s Correlation coefficient

P value

BASDAI

0.157

0.120

ESR (mm)

0.040

0.696

CRP (mg/l)

0.046

0.653

Occiput-wall distance (cm)

0.317

0.001

Chest expansion (cm)

0.374

<0.001

Schober index (cm)

−0.368

<0.001

BASFI

0.289

0.004

BASRI

0.349

<0.001

BASDAI bath ankylosing spondylitis disease activity index, ESR erythrocyte sedimentation rate, CRP C-reactive protein, BASFI bath ankylosing spondylitis functional index, BASRI bath ankylosing spondylitis radiologic index

Statistically significant P < 0.05

Discussion

In the present study, we state an important diagnosis delay among Moroccan AS patients. The average diagnosis delay was 4.12 ± 3.99. Previous studies, in particular that of Dincer et al. [1], have found an important diagnosis delay in their population as the result of our study. In fact, AS has the longest diagnosis delay among Rheumatic diseases, with a period of 5–10 years [1, 5, 13, 14]. It is rather frustrating, especially now with the availability of effective treatment modalities for this disease in its early stages [6]. It should be noted that diagnostic criteria of AS rely on the presence of radiographic sacroiliitis, which frequently appears late in the course of the disease [15]. Thus, a long delay may exist between onset of symptoms and establishing diagnosis [1, 15]. To diagnose AS in early stages, the Berlin algorithm was proposed with a diagnosis probability of 90% [16]. In our population, the importance of diagnosis delay could be explained by the fact that most of our patients are referred from different cities to the Rheumatology Department of our hospital which is a national tertiary referral center. Also, this delay could be related to the low socio-economic status with precarious hygienic conditions in Moroccan AS patients and the lack of a health-care system [7]. In our study, the delay of diagnosis was consistent in juvenile-onset ankylosing spondylitis (JoAS) patients and adult-onset ankylosing spondylitis (AoAS). Contrary to our result, Stone et al. have found that JoAS patients experience a greater delay in diagnosis compared with AoAS patients [17]. Our result could be explained by the low proportion of JoAS patients in our population (16%) compared with AoAS patients. In their data, Dincer et al. noticed that the average of diagnosis delay was higher in patients with low educational level [1]. In our data, there was no impact of educational level on diagnosis delay. It is noteworthy that the majority of our population is represented by illiterate persons (45%) against only 15% in Dincer’s et al. data [1]. Also, there was no association between professional status and diagnosis delay. In fact, a large proportion of our patients (59%) were unemployed. On the other hand, diagnosis delay was not higher in patients with extra-articular involvement. In Aggarwal et al. data [6], patients with extra-articular manifestations had an important diagnosis delay. Such a result could be related to the high proportion of patients with extra-articular manifestations (34%) comparing to our data (10%). Delayed diagnosis in our AS population led to more severe functional disability and radiologic damage. Furthermore, diagnosis delay had no impact on disease activity. Our population of AS patients had severe disease but moderately active. In fact, in a previous study that evaluates characteristics of AS in Morocco, El Mansouri et al. [7] noticed that AS is most likely severe in Moroccan patients, with a young age onset and severe functional disability. Otherwise, it has been shown that anti-TNF agents have an impressive effect on active disease [18, 19] but also function, mobility, and other disease parameters [1, 4, 20]. This effect is mainly conditioned by early diagnosis [4]. So, an early treatment of AS is important for slowing down disease progression before the installation of severe structural damage. We have also explored relationship between diagnosis delay and radiographic damage. Rudwaleit et al. confirm that radiographic changes are considered to be an indicator of chronicity and severity and reflect structural damage that is altered the delay of diagnosis [19]. Radiologic changes and particularly sacroiliitis have low sensitivity, specificity and likelihood ratio than magnetic resonance imaging which can recognize pre-destructive changes [1, 20]. Taking into account the young age at onset and given the high frequency of severe functional disability in Moroccan AS, it is necessary to establish an early diagnosis based on new diagnostic criteria especially with the avenement of imaging modalities such as magnetic resonance imaging.

Conflicts of interest

None.

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© Springer-Verlag 2010