Epidemiology and Management of Immune Thrombocytopenia in Adult Patients in Algeria: A Non-Interventional, Longitudinal, Nationwide Estimation Study

Background: Immune thrombocytopenia (ITP), is an acquired immune mediated disease characterized by a platelet count of <50×10³/mm³, accelerated destruction of platelets from peripheral circulation, and impaired platelet production. Diagnosis is based on exclusion of other causes of thrombocytopenia. Treatment goal is to ensure sufficient platelet count to prevent bleeding. ITP occurs mainly in women, either at the onset of puberty, or in their 3^rd/4^th decade, with higher mortality in older patients. To date, no accurate epidemiological data on ITP is available for Algeria. This study assessed the incidence (by age, sex, diagnosis stage, and province), prevalence, characteristics, and treatment regimens received by ITP patients (pts) in Algeria.

Methods: This non-interventional, longitudinal, nationwide estimation study investigated the epidemiology and care of ITP pts treated in public hospitals in Algeria from September 2017─August 2018. Data were collected at inclusion visit on a case report form. Data on bleeding score and platelet count were also collected after study termination. Pts ≥16 years (y) of age, either previously (before 1^st September 2017) or newly (September 2017─August 2018) diagnosed with ITP, having given written consent, were included. The incidence and prevalence of ITP were estimated with Poisson distribution (95% confidence interval [CI]).

Results: Overall 1,746 pts were listed, of whom 587 without consent. Of the 1,164 enrolled pts, 1,159 were included (male: 264 [22.8%]); 5 pts (0.4%) were excluded for major protocol deviations. Among eligible pts, 173 (14.9%) were newly and 986 (85.1%) had been previously diagnosed with ITP. No comorbidities conferring bleeding risk were found in 966 pts (83.3%). At diagnosis, median age was 36y (quartiles: 25y, 50y) and platelet count (10³/mm³) was 0-30 in 124 (71.7%), 30-50 in 20 (11.6%), and 50-100 in 28 (16.2%) pts. Khellaf score was ≤8 for 45 (26.0%) and >8 for 8 (4.6%) pts; 120 pts (69.4%) had missing Khellaf score. Bleeding risk (as per WHO bleeding score) was low (grade 0) in 50 (28.9%), grade I in 24 (13.9%), grade II in 34 (19.7%), grade III in 52 (30.1%), and grade IV in 13 (7.5%) pts. 55 (31.8%) pts were asymptomatic, 58 (33.5%) were ecchymotic, and 60 (34.7%) were severely hemorrhagic. Steroids comprised the major treatment for both new (n [%]: 136 [78.6]) and previously (795 [80.7]) diagnosed ITP pts. First line ITP treatments included corticosteroids (937 [80.8]), immunoglobulins (39 [3.4]), antineoplastic agents (15 [1.3]), rituximab (14 [1.2]) and antibacterials (2 [0.2]). Last/ongoing treatments at inclusion comprised corticosteroids (712 [72.2]), rituximab (56 [5.7]), immunoglobulins (30 [3.0]), romiplostim (19 [1.9]), and antibacterials (4 [0.4]). Among previously diagnosed ITP pts, 172 (17.4%) had a splenectomy with a median time from ITP diagnosis of 19 months.

Incidence of ITP in pts ≥16y was 0.85 cases (95% CI: 0.75, 0.96) per 100,000 inhabitants. Incidence increased with age from 0.5 (95% CI: 0.43, 0.68) in pts aged 15-35y to 2.4 (95% CI: 1.60, 3.51) in pts ≥75y old. Female pts had a higher incidence of ITP (1.2 [95% CI: 1.02, 1.37]) vs male pts (0.5 [95% CI: 0.43, 0.67]; male:female ratio 0.3). Incidence of ITP varied with diagnosis stage (asymptomatic: 0.4 [95% CI: 0.31, 0.45]; ecchymosis: 0.1 [95% CI: 0.10, 0.19]; severe hemorrhage: 0.1 [95% CI: 0.06, 0.13]), and province (lowest: 0.1 [95% CI: 0.02, 0.92] in a public site in Tebessa; highest: 1.6 [95% CI: 0.93, 2.89] in a public site in Sidi Bel Abbès).

Prevalence of ITP was 5.7 (95% CI: 5.39, 5.93) per 100,000 inhabitants. Prevalence increased with age from 3.2 (95% CI: 2.78, 3.67) in pts aged 15-25y to 11.9 (95% CI: 9.68, 13.08) in pts aged 65-75y, then decreased in pts ≥85y old (7.6 [95% CI: 4.79, 12.06]). Female pts had a higher prevalence of ITP (8.8 [95% CI: 8.33, 9.29]) vs male pts (2.6 [95% CI: 2.34, 2.85]).

Conclusion: The incidence and prevalence of ITP in Algeria were higher in females and increased with age conforming to global trends, but lower than occidental data thus requiring further investigations. Corticosteroids were the most commonly used agents in different lines of treatment; splenectomy was the second option in cases of corticosteroid failure. Rituximab and romiplostim were the last/ongoing treatment before inclusion for a small number of pts. The study highlighted the need for more data on the use of romiplostim prior to splenectomy for adult ITP pts in Algeria.

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