Background There is a worldwide variation in the incidence of childhood manifestation of systemic lupus erythematosus (SLE), which may be related to geographical and ethnic factors. In Oman,there are different ethnic groups which include Arab descent and non- Arab descent. More than half of Oman’s population is Arab. However, large numbers of ethnic Baloch—who migrated to Oman from Iran and Pakistan over the past several centuries—live near the coast in Batina region and Muscat urban area.The inhabitants of the Dhofar mountains are ethnically distinct from the coastal Arabs and are thought to be descendants of people from the Yemen highlands. There are no data available on geographical differences in ethnicity among different regions in Oman, however, the majority (if not all) of the Omani’s from Sharqiya region are of Arab descent. Anecdotal reports suggest that most of SLE cases in Oman are from Sharqiya region.
Objectives The objective of this study is to study identify regional variations in the manifestations of SLE including disease frequency, serological changes, organ involvement and overall prognosis in Oman.To determine if clustering of disease does occur in the Sharqiya region as suggested anecdotally.
Methods We retrospectively reviewed the hospital charts of 104 consecutive children with childhood onset SLE who were seen in all the pediatric rheumatology centers in the Sultanate of Oman over a 15-year period between 1995 and 2010. A data collection format was designed which included demographic, clinical and laboratory data. Disease activity score (SLEDAI) was also collected.
Results Among the 104 children with SLE studied,(41%) were from the Sharqiya region, Batina (18%), Muscat (17%), and Dakhiliya (10%).There were significantly more males in the Sharqiya region compared to the rest of the country (42% versus 15%; p=0.002). Children from the Sharqiya region tended to be younger (10.3 versus 16.5 years; p=0.001), diagnosed much earlier (6.4 versus 9.4 years; p<0.001), and had more familial cases of SLE (58% versus 33%; p=0.010) than those children from the rest of the Sultanate.
With regards to clinical parameters, the Sharqiya children also had increased incidence of mucocutanous changes (81% versus 62%; p=0.036) and decreased hematological abnormalities (30% versus 51%; p=0.036). With regards to serological parameters of the study cohort, Sharqiya region tended to have low incidence of children with Ro/SSA (7% versus 18%; power=26%), La/SSB (7% versus 15%; power=13%), Anti-RNP (7% versus 18%; power=26%), and Anti-Sm (9% versus 20%; power=20%). However, these results should be interpreted with caution due to low power. However, there were no significant differences in disease severity (SLEDAI) between Sharqiya and the rest of the Sultanate (14 versus 14; p=0.950) and overall prognosis.
Conclusions Geographical clustering of childhood onset SLE was demonstrated in the Sharqiya region of Oman. Unique features were also demonstrated in this cohort of patients notably more boys presenting at a younger age at onset with increased incidence of familial cases SLE than rest of Oman. Although, this study is not without limitation, future genetic studies will now be undertaken in the Sultanate of Oman targeting families in Sharqiya region with familial SLE to detect new gene mutations.
Disclosure of Interest None Declared