Outcome of patients with primary and secondary hemophagocytic lymphohistiocytosis: A retrospective analysis from a tertiary care center

Hemophagocytic lymphohistiocytosis (HLH) is a progressive and potentially life-threatening disorder. It is classified into primary and secondary HLH. The objective of our study was to determine the outcome of primary and secondary HLH in pediatric and adult patients based on HScore and treatment modality. We conducted a retrospective analysis done from July 2010 to June 2020. Variables analyzed included age, gender and history of death in siblings. HScore was used for disease classification while clinical and laboratory findings which were required to fulfill the HScore diagnostic criteria were also recorded. Continuous variables were summarized as median and categorical variables as frequencies and percentages. Categorical variables were compared using chi-square test and Fisher Exact test. Significance of different variables between primary and secondary HLH was calculated using independent-samples t test. A P value of <.05 was taken as significant. A total of 51 patients were included in the analysis (41 in primary and 10 in secondary HLH group). In primary HLH, 36 patients were in the pediatric age group and 12.2% had a history of death in sibling. All 41 patients had increased ferritin and decreased fibrinogen levels. The overall survival in primary HLH was 44%. In the secondary HLH group, viral infections were the most common etiology and ferritin was increased as well. The overall survival in secondary HLH was 60%. The median survival was 15 ± 4.8 months. The overall survival of both groups combined was 53%. Primary HLH should be considered in pediatric patients who present with pancytopenia and hepatosplenomegaly. In centers where genetic testing is not available, HScore along with serum ferritin and fibrinogen is a good substitute for disease classification.