Although several studies have supported the theory that spondyloarthritis was rare in sub-Saharan Africa, partly due to the rarity of the HLA B 27 antigen [13–15]. However, recent studies suggest that the relationship between HLA-B27 and SpA in sub-Saharan Africa may be more complex [17]. Over time, SpAs have emerged in black African literature, particularly in Senegal [12], the Democratic Republic of Congo [11], Burkina Faso [18] and Togo [9]. We report a series of 275 cases with a male predominance and the HLA B 27 antigen was present in 49.6% of cases. The average age of our patients was 47.28 ± 15.49 at the time of diagnosis with extremes of 14 and 92 years.
The average age during spondyloarthritis is variously appreciated, we report in our study an average age of 39.7 ± 11 years with extremes of 10 and 80 years both say that in Senegal, Abba et al reported an average age of 47.28 ± 15.49 at diagnosis with extremes of 14 and 92 years [12]. In a study carried out among rheumatologists in the Auvergne region, 10% of inflammatory rheumatism diagnosed after the age of 60 is spondyloarthritis compared to 38% before this age [19]. Nevertheless,our results agree with those of the literature which stipulate that spondyloarthropathies are aa group of conditions that affects young adults, with onset of symptoms between 20 and 40 years of age in the majority of cases [20], moreover the ASAS criteria for axial spondyloarthritis require an onset before 45 years of age [21].
During our study, we observed a male predominance of 54.8%. This result is different from that obtained by Condé et al; Abba et al in Senegal [12, 22]. But the male predominance is classic in spondyloarthropathies as noted in several African and Western studies [18, 23, 24]. Despite the fact that SpA affects men more frequently and more severely than women, it is increasingly believed that the proportion of female patients is higher than initially thought, with women having less severe clinical manifestations [25 ]. Our results are comparable to those of Awada [26] and Jabbouri [27] who found lumbar involvement in respectively 82.65% and 83.2%82% of cases. As for peripheral damage, it was present in 40.7% of patients in our study. In effect, Alaya et al [24] reported 46.8%. However, Abba et al in Senegal reported 33.23 peripheral involvement [12].
The extra-articular manifestations present in our series were uveitis in 9.6% and aortic insufficiency in 7%. In Burkina Fasso, Ouédraogo et al did not find any extra-articular manifestationsin their study [18]. However, several other African studies have shown a relative absence of extra-articular manifestations[21.28]. In our study,HLA-B27 phenotyping was performed in 125 patients, 62 patients were HLA-B27 positive (49.6%). Few studies have focused on HLA B27 in the African black series. Its prevalence varies according to ethnicity, 7.8% among the Fulani in Gambia [29] and 9.7% in Mali [30]. In populations of southern and central Africa,HLA B27 is particularly rare. Its frequency is estimated at less than 1%[14].On the other hand, the prevalence in Western Europe is 6.9 to 16% [2]. Possible explanations for these differences could be unidentified protective genetics or environmental factors.
Treatment was based on nonsteroidal anti-inflammatory drugs 225 (81.8%). SpA treatment is largely limited to nonsteroidal anti-inflammatory drugs and physical therapy. The use of biological treatments (anti-TNF) is limited due to the high cost of these biomedicines. Only two patients received biological treatment in our study [20].