Characteristics and factors associated with remission in Moroccan patients with severe rheumatoid arthritis

¹Laboratory of Human Pathologies Biology, Department of Biology, Faculty of Sciences, and Genomic Center of Human Pathologies, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Morocco, ²Laboratory Autoimmunity, Department of Immunology, National Institute of Hygiene, Rabat, Morocco, ³Higher Institute of Nursing and Health Techniques, Dakhla, Morocco, ⁴Mohammed V University, Faculty of Medicine and Pharmacy, Military Hospital, Rheumatology Department, Rabat, Morocco, ⁵Laboratory of Microbiology and Molecular Biology, Faculty of Science, Mohammed V University, Rabat, Morocco, ⁶Scientific Institute, Mohammed V University Rabat, Morocco

^&Corresponding author
Hakima Missoum, Laboratory of Human Pathologies Biology, Department of Biology, Faculty of Sciences, and Genomic Center of Human Pathologies, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Morocco

Introduction    

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation and synovial hyperplasia, which gradually leads to cartilage and bone destruction and ultimately results in functional disability. It can also cause extra-articular systemic manifestations affecting the skin, eyes, heart, lungs, kidneys, nervous system, and gastrointestinal tract. The worldwide prevalence is between 0.5 to 1% [1] and in Morocco the number of estimated cases is around 350,000 [2]. The incidence is highest between 40 and 60 years of age, with women being three times more affected than men [3]. The incidence, severity, and outcome of the disease vary among different ethnic groups [4]. This variability is linked to the socio-economic level and development of countries, as well as genetic and/or environmental factors [4-6]. Rheumatoid arthritis is defined according to the ACR/EULAR 2010 criteria, which integrate clinical, biological, and radiological parameters [7].

Risk factors for RA include genetic susceptibility, gender, age, smoking, infectious agents, hormonal influences, and ethnic factors [8]. Two important autoantibodies have been described in RA: rheumatoid factors (RF) and autoantibodies to citrullinated peptides/proteins (ACPA or CCP2). These autoantibodies are widely used in clinical practice [9-12]. Concerning information on demographic and clinical characteristics, therapy, and co-morbidities in RA patients, these factors have been less explored in developing countries. These characteristics not only lead to the worsening of the disease but also to an increase in mortality and healthcare costs [13]. In Morocco, the exact incidence of RA has not been established yet. However, the disease has a significant impact on socio-professional activity and the economic situation of affected patients [14,15].

The management and prognosis of rheumatoid arthritis (RA) have significantly improved in recent years, leading some authors to consider it a relatively benign condition. Emerging treatments, such as biologics and Janus kinase (JAK) inhibitors, have revolutionized RA management, making remission a realistic goal and a primary therapeutic target in clinical practice [16,17]. In developing countries like Morocco, the utilization of biologic therapies is constrained by their high cost and limited healthcare coverage [11,18,19]. For patients with unfavorable prognostic indicators, the utilization of biologic disease-modifying anti-rheumatic drugs (bDMARDs) is recommended following the inadequacy of methotrexate therapy [20]. Clinical remission based on the Disease Activity Score 28 (DAS28) is the most frequently employed definition both in clinical practice and in clinical trials [21,22]. This study aimed to delineate the sociodemographic and clinical profiles of rheumatoid arthritis (RA) patients receiving treatment at the Rheumatology department of the Military Hospital in Rabat, Morocco. Additionally, the study aimed to assess their ongoing therapeutic regimens and to identify factors correlated with achieving remission. Furthermore, it sought to ascertain any potential associations between specific factors and the attainment of remission in these patients.

Methods     

Study population and disease characteristics: this cross-sectional study enrolled 111 patients diagnosed with severe rheumatoid arthritis (RA) who were admitted to the rheumatology department of the Military Hospital in Rabat, Morocco, between September 2017 and April 2018. The diagnostic criteria for RA were based on the guidelines outlined by the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) for the classification of RA in 2010 [21,22]. The calculated Disease Activity Index 28 C-Reactive Protein (DAS 28CRP) [23] and the Health Assessment Questionnaire (HAQ) [24] were applied to RA patients to measure the clinical activity and functional disability, respectively. Exclusion criteria for RA patients included other forms of inflammatory arthritis, such as psoriatic arthritis, reactive arthritis, spondylarthropathy, and inflammatory bowel disease. All participating patients provided written informed consent. Ethics Committee approved this study by “IORG Number: IORG0006594-Morocco, 70/17”. Demographic, clinical, laboratory, and treatment data were collected. Sociodemographic information included: age, gender, duration of RA evolution, body mass index (BMI), consanguinity, smoking, family history, alcohol consumption, occupation, depression, and erosion. Information on comorbidities and extra-articular manifestations included fracture, infection, vaccination history, type 2 diabetes, hypertension, hypercholesterolemia, hypertriglyceridemia, cardiovascular disease, cerebrovascular disease, cancer, lung disease, digestive disease, osteoporosis, and Sjogren's syndrome. Laboratory variables included erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) anti-cyclic citrullinated peptide (ACPA or anti-CCP2) and rheumatoid factor IgM (RF IgM), ANA. Radiographs (X-rays) of hands and feet were evaluated for the presence and location of joint erosion. The treatment for RA comprised oral corticosteroids, conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate, leflunomide, and sulfasalazine, and biologic therapies including synthetic biologic DMARDs (bDMARDs) like anti-TNF alpha agents, rituximab, and tocilizumab.

Immunological tests: the sera underwent testing via Indirect Immunofluorescence (IIF) for anti-DNAdb, ELISA for the detection of soluble anti-antigen antibodies ANA6 Profil, and immunodot for anti-ANA antibodies profile 3 plus DFS70. All assays were conducted at the Autoimmunity Laboratory of the National Institute of Hygiene (Rabat, Morocco) utilizing an automated system (Biorad system PhD™) and immunodot techniques.

Indirect immunofluorescence (IIF): the test for anti-DNA antibodies was performed by IF using Crithidia luciliae (Bio-Rad Laboratories, CA) as substrate and the clinically significant titer was 1:5.

Enzyme -Linked Immunosorbent Assay (ELISA): the ANA6 profile antigens (anti smith antibody (Sm), anti-ribo-nucleoprotein antibodies (RNP), anti-Ro antibody (anti SSA), anti-la antibody (anti-SSB), anti histidyl-tRNA synthetase antibodies (jo1), anti-topoisomerase I antibody (Scl-70)) were performed by ELISA (Bio-Rad Laboratories. Positive anti-ENA was defined as a serum concentration >25EU. Serum samples were processed in initial dilution of 1:101for the detection of anti- anti-ANA6 profile.

Immunodot: the immunodot technique was utilized to identify additional antigen specificities not detected by Elisa ANA 6 profile. The anti-ANA antibodies profile 3 plus DFS70 (Euroline/Euroimmun) was employed, targeting antigens such as SSA/Ro-52, Dense Fine Speckled (DFS70), PM/Scl (PM-100), centromere-protein (CENPB), Proliferating Cell Nuclear Antigen (PCNA), Nucleosome, Histone (HIS), ribosomal proteins (RIB), mitochondrial antibodies (AMA-M2), and parietal cell antibodies (PCA).

Statistique analyses: socio-demographic characteristics were presented as mean with standard deviation (SD) for continuous variables and as number and percentage for categorical variables. Statistical analyses were conducted using STATISTICA StatSoft 12.0 Software (Tulsa, Oklahoma, USA). The association between socio-demographic characteristics of RA patients and the control groups was assessed using the Chi-square test (?2). Prevalence ratio (PR) was calculated to evaluate risk factors. A significance level of p ≤ 0.05 was used for all tests based on descriptive statistics. Patients were stratified into four groups based on RF and ACPA status: RF+/ACPA+, RF+/ACPA-, RF-/ACPA+, and RF-/ACPA-. Comparisons of demographic and treatment characteristics among different RF and ACPA statuses were analyzed using the Chi-square test (Χ²) and Prevalence ratio (PR) for categorical data. A p-value of <0.05 was considered statistically significant.

Ethics: Ethics Committee approved this study for Biomedical Research of Faculty of Medicine and Pharmacy of Rabat (CERB), (IORG Number: IORG0006594), Morocco (Reference Number: 70/17).

Results     

Sociodemographic and clinical characteristics

The analysis included 111 patients, with a mean age of 57.1 years. The majority of patients (84.7%) were female, resulting in a female-to-male ratio of 5.5:1 (94 women and 17 men). Additionally, 94% of the patients were over 45 years old. The mean BMI was 27.5. Approximately 35.1% of patients reported a family history of RA. Among the total number of patients, 12.5% were active smokers, 11.7% reported alcohol consumption, and 6.31% were experiencing depression. The majority of patients were married, with 20.7% reporting consanguineous marriages, and 30% experiencing menopause. In terms of occupational status, 69% were housewives, 13% were retired, 12% were housekeepers, and 6% were civil servants. In terms of disease progression from the time of diagnosis, we observed an average duration of 12.14 ± 8.26 years, ranging from a minimum of 1 year (diagnosed on admission) to a maximum of 35 years. About 6.3% of patients had less than 24 months of disease progression upon admission. However, a significant portion, totaling 57.6% of patients, had experienced more than 9 years of disease progression, highlighting the chronic nature of this condition. Serum rheumatoid factor levels were positive in 95.5% (106/111) of patients, while anti-citrullinated peptide antibodies were present in 80% (n = 84/111) of patients. Based on RF and ACPA status, 80% of patients were RF+/ACPA+, 14.4% were RF+/ACPA-, none were RF-/ACPA+, and 2.4% were RF-/ACPA-. The mean ESR and CRP levels were 34.04 ± 25.01 and 23.19 ± 28.62, respectively. Erosions on X-rays were observed in 62.2% of patients. The characteristics of the study RA patients are summarized in Table 1.

Risk factors and comorbidities

Of the total number of patients, 12.5% reported active smoking. Comorbidities associated with the diagnosis of RA were observed in 77.5% of patients, with osteoporosis being the most common (47%), followed by Sjögren's syndrome (34.2%), infection (33.3%), and hypertension (27%). Table 1 provides a detailed overview of the frequency of comorbidities in RA patients.

Level of activity and functional status of the disease

The level of activity (DAS-28 CRP) of the patients at inclusion was calculated for 105 patients with complete information (Table 1). The mean disease-related activity was moderate (3.67 ± 1.73). Patients were then categorized into four groups based on their DAS-28 CRP scores: 32.4% were in remission, defined as a score = 2.6; 15.2% had low disease activity (DAS-28 CRP = 3); 23.28% had moderate disease activity (DAS-28 CRP = 5.1); and 28.6% had high disease activity (DAS28 > 5.1). According to the Health Assessment Questionnaire (HAQ), patients exhibited varying degrees of functional disability in performing daily activities (mean HAQ-DI = 1.58 ± 0.64). Specifically, 22.5% of patients had mild HAQ scores, 49.6% had moderate HAQ scores, and 27.9% had severe HAQ scores.

Immunological status

The prevalence of autoantibodies detected in all sera is presented in Table 2. At diagnosis, ANA were positive in 84.68% (94/111) of the total number of patients. The most frequently observed fluorescence patterns of ANA by IFI technique were speckled (53.2%) and homogeneous (23.4%), followed by nucleolar (11.7%), homogeneous and speckled (4.3%), speckled and nucleolar (3.2%), cytoplasmic fluorescence (2.1%), and PCNA (1.1%) patterns. At the time of inclusion, among the ANA-positive patients, 5.4% (50/94) tested positive for anti-dsDNA, and 45% (50/94) tested positive for anti-ENA. Among the anti-ENA autoantibodies, anti-SSA 64kD showed the highest specificity in RA patients (30%), followed by anti-SSB in 12% of cases, anti-Scl-70 in 10%, anti-SSA/Ro52 KD and anti-DFS70 each present in 8% of cases, anti-Sm/RNP in 6% of cases, and anti-Jo-1, histone, nucleosome, PM-SCL100 (PM100), and AMA-M2 each at low frequency in 4% of patients. Anti-centromere B (CB), ribosomal protein (RIB), and anti-Sm antibody were present in only 2% of cases, respectively.

Medications

As shown in Table 1, among all RA patients, 97 (87.4%) were receiving oral corticosteroid therapy, and 110 (99.1%) were receiving one or more disease-modifying anti-rheumatic drugs (DMARDs) or biologic DMARDs (bDMARDs). In DMARD therapy, 91.9% were on methotrexate (MTX), 22.5% were on Salazopyrine, and 4.5% were on leflunomide. Additionally, 63% were on bDMARD therapy. Among bDMARD therapies, 17 patients (84.3%) were on Rituximab (RTX), 17 patients (24.3%) were on anti-TNFalpha agents (Etanercept, Infliximab, Adalimumab), and 10 patients (14.3%) were on Tocilizumab (TCZ).

Correlation of the characteristics of RA patients with remission

The association of remission with demographics, clinical, laboratory, and treatment of RA patients was presented in Table 3. According to DAS 28 (CRP), 34.4% (43/105) of patients had DAS 28 (CRP) < 2.6 and were in remission. Patients in remission showed fewer erosions, less osteoporosis, and lower HAQ scores than those without remission, but the correlation was not statistically significant. However, statistically significant correlations were found for ACPA positivity (P < 0.001), ANA positivity (P = 0.001), and bDMARD treatment (P = 0.01). There was no significant difference according to age, BMI values, menopause, tobacco and alcohol use, consanguineous marriage, duration of disease course, RF, MEFV mutations, infection, hypertension, fracture, lung disease, digestive disease, Sjogren's syndrome, depression, cancer, corticoid, and DMARD treatment.

Discussion     

Rheumatoid arthritis (RA) is a heterogeneous disease, presenting with varying clinical features and characteristics. However, data on severe RA in Morocco is limited. This study aims to describe the characteristics and factors linked to remission among 111 patients diagnosed with severe RA, who were referred to a specialized Rheumatology unit and actively treated with disease-modifying drugs, including bDMARDs. The observed characteristics align with those reported in previous studies, reflecting a comparable disease burden characterized by a high prevalence of comorbidities, typical of a chronic degenerative disease. When examining gender distribution, we noted a significant predominance of females, accounting for 84.68% of the cases, with a sex ratio of 5.5:1. This finding aligns with previous cohorts from various regions, including the United Arab Emirates (4:1), Iran (7.1), Algeria (5.9:1), Latin American countries (5.2:1), and South Africa (6.9:1) [25-27], but it is higher than European countries and the USA where the ratio is 3:1 [28]. The female predominance in RA may be influenced by various factors, including clinical and demographic aspects, as well as hormonal influences, which exert complex effects on the immune system [29]. This gender discrepancy could potentially elucidate the higher susceptibility of women to RA compared to men. Nonetheless, the underlying reasons for the rarity of the disease in men still lack clarity and warrant further investigation in future studies. Differential patterns in seeking medical consultation and symptom perception have been noted, with men displaying a lower propensity to seek medical advice and potentially underestimating symptoms [30]. Female gender has been identified as a prognostic factor in RA, with disability progression occurring three times faster in women compared to men [31,32].

In our study of RA patients, we observed that 11% were smokers, a finding consistent with previous reports in the literature, where smoking rates ranged from 9.2% to 10.6% [25]. Indeed, smoking is widely acknowledged as a significant factor in both the development and severity of RA [25]. The low frequency of smoking in our series can be attributed to the high number of women included. The high prevalence of consanguineous marriage raises questions about potential genetic predisposition factors. Conversely, depression was found to have a low prevalence in our population, likely influenced by the management of RA.

We observed a high frequency of erosion, indicating significant joint damage. Additionally, the majority of RA patients in our study were housewives, followed by retired individuals and housekeepers in terms of professional status. Our study reveals that the majority of RA patients have comorbidities such as osteoporosis, Sjögren's syndrome, infection, and hypertension. These findings align with previous literature on the subject [25,28,31,33]. Comorbidity remains a major problem for patients with RA in all countries [34], it adds significant complexity to patient care, making diagnostic and treatment decisions more difficult [28].

The high frequency of extra-articular manifestations observed in RA patients, including osteoporosis (47%), Sjögren's syndrome, pulmonary, and cardiovascular manifestations, is consistent with findings in the literature [35-37]. Extra-articular manifestations in RA are prevalent and can affect multiple organs. In our study, approximately half of the patients developed systemic involvement. Several factors contribute to the occurrence of these manifestations, including the chronicity of the disease, as evidenced by our findings and other studies. Additionally, the advanced age of our population is noteworthy. However, the prevalence of cancer was notably low in our study, likely due to inadequate regular screening practices attributed to the socio-economic status of the patients. This study revealed that the majority of patients fell into the high or moderate disease activity categories (67.8%), with 32.4% achieving remission. Additionally, 27.9% of patients had HAQ scores greater than 1.5. When patients were stratified based on DAS 28 scores, those in the group with scores below 2.6 exhibited lower HAQ scores compared to the non-remission group, indicating less functional disability. Similar trends have been observed in previous studies [38].

In RA studies, remission rates vary from 3% to 68% [39] depending on the selection of remission criteria, patient selection, length of follow-up period, and therapy. Similarly, a high remission rate was reported in Finland (36%) and in the USA (36%) [40]. Regional data from the United Arab Emirates did not align with our findings; they reported a mean DAS 28 of 5.2, with only 12% of their patients falling into the low activity categories of disease or remission [38]. In another regional study by Lutf et al., findings differed from our study in a heterogeneous group of patients with RA. Their mean DAS 28 was 2.85, with 49% of patients in remission [41]. Our high remission rate, compared to Algeria's (14%), can be attributed to our patients receiving biotherapy. In Western populations, the mean DAS 28 did not align with our findings. In the ESPOIR cohort, the mean DAS 28 was 5.1, but the remission rate was similar (30%) to our present study [42]. This variation might be elucidated by improved access to care and the availability of a wider range of biological agents. Numerous studies have pinpointed various factors influencing the selection of the initial bDMARDs in RA patients. The correlation analysis between the characteristics of RA patients and their remission status revealed a positive association between remission and ACPA positivity (P<0.001). These findings align with those reported in previous studies [43,44]. The presence of ACPA positivity was associated with a more favorable therapeutic response, indicating that our patients received better management. RA was correlated with anti-CCP positivity, longer illness duration, and higher scores for all patient-reported outcome measures (PROMs). Existing literature indicates that remission can be attained equally in both antibody-positive and -negative patients, although the quality of remission may be less stringent in anti-CCP positive individuals, as they often experience more tender joints and residual swelling [22]. Moreover, the disappearance of clinical disease does not coincide with changes in the humoral response of ACPA in the serum [44].

Out of our total patients, 84.7% tested positive for ANA. Among those with a DAS 28 score below 2.6, 94.1% were ANA positive, whereas among those with a DAS 28 score above 2.6, 78.9% were ANA positive. This difference between the groups was highly significant (P=0.001). The presence of ANA is likely attributed to extra-articular autoimmune manifestations such as Sjogren's syndrome and lung disease observed in our population. These results were corroborated by the antigenic specificity of ANA found, with 30% positive for anti-SSA/Ro64 Kd, 12% for anti-SSB/La, 8% for anti-SSA/Ro52kd, and anti-DFS70. Anti-DFS70 is considered a positive predictor for the development of systemic rheumatic autoimmune disease [45]. These results are comparable to those in the literature [23,46,47]. It was observed that the disappearance of autoantibodies was rare, and patients who achieved the best possible outcome in RA did not become seronegative more frequently than patients with persistent disease [44]. RA is a chronic inflammatory disease, where the pathology induced by autoantibodies contributes to the inflammation and destruction of the joints [48]. In our study, 63% of our patients received bDMARDs. Comparatively, in other studies, the utilization of bDMARDs ranged between 72% and 89%. Given that the majority of our patients had severe RA, bDMARD usage was more prevalent among those with a DAS 28 score above 2.6. Despite the introduction of biotherapy, as indicated in the literature, approximately 30% of patients fail to achieve remission [49].

Conclusion     

The current study provides a contemporary analysis of the clinical features of severe RA, offering valuable insights into the actual clinical efficacy of treatments for patients. Among a cohort of RA patients under rheumatologist care, approximately 34% exhibited remission or low disease activity, while more than two-thirds had severe disease, contrasting with findings from RA patients in Western populations. This understanding of disease characteristics will enhance our comprehension of RA severity and activity within the rheumatoid population receiving treatment in Moroccan hospitals. Furthermore, it may facilitate the assessment of patients eligible for novel biological therapies. Additionally, this study adopts a real-life design in a developing African nation, offering insights into remission rates among patients with severe RA undergoing bDMARD treatment. Clinical remission stands as a crucial outcome in RA management, with broad implications for clinical practice and regulatory approval of novel therapies. Attaining clinical remission can foster improved disease management and is linked to significant economic advantages.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Conception and study design: Hakima Missoum and Youssef Bakri. Data collection: Hakima Missoum, Hamza Toufik and Abdellah El Maghraoui. Data analysis and interpretation: Hakima Missoum, Najlae Adadi, Mohammed Alami. Manuscript drafting: Hakima Missoum. Manuscript revision: Najlae Adadi, Mohammed Alami, Fatima Bachir and Youssef Bakri. Guarantor of the study: Hakima Missoum. All authors approved final version of the manuscript.

Tables     

Table 1: characteristics of the patients with RA

Table 2: profile of auto-antibodies of the patients with RA and control groups

Table 3: correlation of the characteristics of patients with RA and their remission threshold according to the DAS28 (CRP) value

References