Features of Ankylosing Spondylitis in Egyptian females

 INTRODUCTION

Spondyloarthritis (SpA) is a group of rheumatic illnesses with comparable hereditary and clinical features. On the basis of the afflicted body regions, these disorders are classified as either axial (axSpA) or peripheral (pSpA). AS is an autoimmune disorder that affects the spine's joints, sacroiliac joints, and surrounding tendons and ligaments. In extreme situations, this inflammation may lead to the development of fibrosis and calcification, resulting in the loss of spinal fusion, spinal flexibility, and a "bamboo" posture. Back discomfort, growing spinal stiffness, and inflammation of the hips, shoulders, peripheral joints, and fingers/toes are the most prominent clinical signs. Inflammatory bowel disease and acute anterior uveitis may also develop together extra-articular symptoms. These extra-articular symptoms vary across East Asian and Caucasian populations. ¹

It was suggested over some years ago through evidence that AS affects women and men differently; the onset of the disorder is often more rapid in males, whereas in women, the diagnosis is typically delayed. Men have lower disease activity as measured by the Assessment of Spondylarthritis international Society (ASAS)-endorsed Disease Activity Score (ASDAS) and the Bath Ankylosing Spondylitis Disease Activity

Index (BASDAI) and a better quality of life by Ankylosing Spondylitis Quality of Life Questionnaire (ASQol), but poorer spinal mobility (Bath Ankylosing Spondylitis Metrology Index, or BASMI) and a more severe by Bath Ankylosing Spondylitis Radiology Index (BASRI). ² Compared to males, women experienced a greater frequency of arthritis, peripheral arthritis, enthesitis, and dactylitis, a poorer response to anti-TNF drugs and a lower quality of life. ³    

On average, women sustain less sacroiliac joint and spinal injuries than males. ⁴

Several extra-articular manifestations (EAM) were shown to be favorably correlated with female gender. ⁵

The aim of this research is to draw attention to the underdiagnosis of AS patients who are female by merging available data on gender variations in AS.

PATIENTS AND METHODS

This is a comparative study which included 60 adult ankylosing spondylitis patients divided into 30 males and 30 females diagnosed according to New York Revised Criteria (2016) for too early AS diagnosis.

Patients were enrolled from Outpatient clinic and the inpatients of Internal Medicine and Rheumatology Departments at:

 Agouza Rheumatology and Rehabilitation center of armed forces.

 Nasser Institute Hospital.

Patients were subjected to the following:

Full History taking as age, gender, disease duration, drug and family history.

Full general and local musculoskeletal examination with special emphasis on axial spine (cervical, thoracic and lumbosacral regions) and examination of sacroiliac joints.

On examination, patients may display evidence of spinal deformity, such as loss of normal lumbar lordosis and kyphosis. Touching the sacroiliac joints may be uncomfortable, and the normal movement of the lumbar and cervical spines, as well as chest expansion, may be impaired. AS is a common cause of a decrease in the range of motion (flexion) of the lumbar spine, as measured by the Schober test.⁶

Schober's test technique:

While the patient is standing, the examiner marks the L5 spinous process by drawing a horizontal line across the patient's back. The height of the second line was 10 cm more than that of the first. The patient is then instructed to reach for his or her toes, and the distance between two lines is measured with the patient fully flexed. The difference between measurements recorded in the upright and flexed positions indicates lumbar flexion. ⁶

Positive Schober’s Test: Less than 5cm increase in length with forward flexion: Decreased lumbar spine range of motion, ankylosing spondylitis.

Modified Schober :Mark with a pen the midpoint between the posterior superior iliac spines (PSIS). Mark two spots with your measuring tape: (1) one that is 10 cm above the PSIS, and (2) one that is 5 cm below it.  As the client bends their spine as much as possible, the distance between the superior and inferior markers is measured and recorded. Less than a 5cm length gain during forward flexion: Ankylosing spondylitis is characterized by a decreased lumbar spine range of motion. 

The best test for identifying clinical sacroiliitis is a positive sacral push test or > 2+ pain on sacroiliac joints or the buttock generated by direct vertical pressure on the center of the sacrum in the prone position. 

 Laboratory investigations: Complete blood count (CBC), C-Reactive Protein (CRP), Erythrocyte Sedimentation rate (ESR) in first hour, liver enzymes and serum creatinine.

Imaging investigations:Plain X-Ray on sacro-iliac joint and spine and MRI on sacro-iliac joint and spine.

Assessment of disease activity using :

The Ankylosing Spondylitis Disease Activity Score (ASDAS)-CRP

Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) .

Statistical analysis:

SPSS version 21 was utilized for analytical purposes. Quantitative data were presented with Mean Standard Deviation, median, range, and Interquartile range and analyzed with the t test (for parametric data) or the Mann Whitney U test (in case of non-parametric data). When categorical data were presented as numbers and percentages, the chi-square test was substituted for the Monte Carlo Exact or Fischer Exact test when deemed unsuitable. P value < 0.05 was considered statically significant.

RESULTS

Table 1: Sociodemographic characteristics in both sexes.

t: Student t test

As regard Sociodemographic characteristics in both sexes, the age was insignificantly different between both studied groups (P value 0.806).

Table 2: Onset of complaints, diagnosis in both sexes

U: Mann Whitney U test IQR: Interquartile range *p≤0.05 (Statistically significant), Regarding the age onset, it was significantly higher in males’ group than females’ group (P value 0.023).

The disease duration in the male group was 7 years while in female group was 7.5 years with no difference between both groups while the onset of diagnosis was statistically difference between both groups as the median was 5 years in males and less in females (median was 2 years).

As regard the delay in diagnosis which is statistically significant between the two groups (P value <0.001) with a median difference in male group was 1.5 years and in the female group was 5.5 years.

Fig. 1: Box and Whisker plot for age of onset in both sexes

Fig. 2: Box and Whisker plot for onset of diagnosis in both sexes

Fig. 3: Box and Whisker plot for delay in diagnosis in both sexes

Table 3: 2016 new york revised criteria for too early diagnosis of AS in both sexes

FE: Fischer Exact test MC: Monte Carlo Exact test

χ 2: Chi square test

*p≤0.05 (Statistically significant),

Regarding New york revised criteria for too early diagnosis of AS in both sexes (2016) there was significant difference between the two arms in lumbar limitations (93.3 % in male group) , SI (30 % in female group is Unilateral SI ≥ GII while in male group 93.4 % is Bilateral SI ≥ G II) , and Score ( median score in male was 9 and in female was 7) while the difference between the two groups in the other items which are inflammatory LBP, Family history, Clinical SCI , HLA B27, Enthesitis and/or arthritis found to be insignificant.

Fig. 4: Lumber limitation in both sexes

Fig. 5: SI in both sexes

Table 4: Extra-articular manifestation in both sexes

FE: Fischer Exact test χ 2: Chi square test

As regard the extra-articular manifestation which are eye involvement, lung, heart and GIT there were no significant different in both sexes as P value was 0.592,0.353,1.000,1.000 respectively).

Table 5: Assesement of disease activity in both sexes

t: Student t test

In assessment of disease activity in both groups there was no significant difference as P value was 0.704 in ASDAS CRP and 0.469 in BASDAI.