Hemophagocytic Lymphohistiocytosis Hospitalizations in Adults and Its Association With Rheumatologic Diseases: Data From Nationwide Inpatient Sample

Epidemiology, characteristics, and outcomes of adult haemophagocytic lymphohistiocytosis in the USA, 2006-19: a national, retrospective cohort study

Background

Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening syndrome characterized by an excessive inflammatory response. Limited data exist on adult HLH.

Methods

In this national, retrospective cohort study, we analysed data from the US National Inpatient Sample database collected between October 1, 2006 and December 31, 2019. Using the International Classification of Diseases (ICD) codes, we identified all adult patients who were admitted non-electively with the diagnosis of HLH. We described demographic characteristics, triggers, and associated conditions. Trends of diagnosis, treatment, and in-hospital mortality were analysed using joinpoint models. In-hospital mortality rates were compared using multivariable logistic regression models that adjusted for demographic characteristics and associated conditions. Finally, we described resource utilization outcomes including cost of hospitalization and length of stay.

Findings

We identified 16,136 non-elective adult HLH admissions. The population pyramid showed a bimodal distribution, with peaks in young adults (16-30 years) and older adults (56-70 years). Joinpoint regression analysis revealed a significant increase in HLH incidence per 100,000 admissions over the study period (Average Annual Percent Change [APC] = 25.3%, p < 0.0001), and no significant change in rates of in-hospital mortality (slope = -0.01; p = 0.95) or administration of in-hospital HLH treatment (slope = 0.46, p = 0.20). The most common associated conditions were malignancy (4953 admissions [30.7%]), infections (3913 admissions [24.3%]), autoimmune conditions (3362 admissions [20.8%]), organ transplant status (639 admissions [4%]), and congenital immunodeficiency syndromes (399 admissions [2.5%]). In-hospital mortality was higher in older adults and males. Furthermore, Congenital immunodeficiency syndromes had the worst in-hospital mortality rate (mortality rate 31.1%, adjusted OR 2.36 [1.56-3.59]), followed by malignancies (mortality rate 28.4%, adjusted OR 1.80 [1.46-2.22]), infections (mortality rate 21.4%, adjusted OR 1.33 [1.10-1.62]), other/no trigger (mortality rate 13.6%, adjusted OR 0.73 [0.58-0.92]), autoimmune (mortality rate 13%, adjusted OR 0.72 [0.57-0.92]), and post-organ transplant status (mortality rate 14.1%, adjusted OR 0.64 [0.43-0.97]). The overall mean length of stay was 14.3 ± 13.9 days, and the mean cost of hospitalization was $54,900 ± 59,800.

Interpretation

We provide insight into the burden of adult HLH in the USA. The incidence has been increasing and the outcomes remain dismal. This signifies the growing need for the development of updated diagnosis and treatment protocols that are specific to adult HLH.

Funding

None.

Nationwide analysis of adult hospitalizations with hemophagocytic lymphohistiocytosis and systemic lupus erythematosus

INTRODUCTION

Hemophagocytic lymphohistiocytosis (HLH) is a well-recognized complication of systemic lupus erythematosus (SLE). This study aims to characterize HLH with and without SLE in the US adult inpatient population.

METHODS

We performed a retrospective study of HLH with and without SLE from the 2016-2019 National Inpatient Sample (NIS) database. We described the demographic characteristics of HLH with and without SLE. Multivariable analysis was performed to calculate odds ratios (OR) for in-hospital death.

RESULTS

A total of 8690 hospitalizations had HLH. Of those 605 (7%) had SLE, and 8085 (93%) did not have SLE. Relative to the non-SLE group, the SLE group was younger, had more females, less whites, more African Americans, more Hispanics, and more Asian/Pacific Islanders. Over 60% of HLH with or without SLE had a concurrent infection. Sixty (9.9%) of HLH hospitalizations with SLE died compared to 1735 (21.5%) of those without SLE. Among HLH hospitalizations, multivariable analysis showed that age (OR 1.02; 95% C.I. 1.016-1.031), Charlson Comorbidity Index (OR 1.15; 95% C.I. 1.091-1.213), infections (OR 3.35; 95% C.I. 2.467-4.557), and leukemia/lymphoma (OR 1.46; 95% C.I. 1.112-1.905) had higher odds of in-hospital death. SLE did not increase the odds of death.

CONCLUSIONS

Inpatients with both HLH and SLE were younger, had a higher proportion of racial/ethnic minorities, and were predominately female. One out of every 10 hospitalizations for HLH ended in death but SLE itself was not an independent risk factor for death. Concurrent infection was the variable most associated with HLH death. Key Points • HLH and SLE group were younger and had higher proportions of female and racial/ethnic minorities. • SLE was not an independent risk factor for death in HLH patients.

Unusual presentation of systemic lupus erythematosus as hemophagocytic lymphohistiocytosis in a female patient: A case report

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disorder, often resulting in the immune-mediated injury of multiple organ systems, including primary HLH and secondary HLH (sHLH). Among them, sHLH results from infections, malignant, or autoimmune conditions, which have quite poor outcomes even with aggressive management and are more common in adults.

CASE SUMMARY

We report a rare case of a 36-year-old female manifested with sHLH on background with systemic lupus erythematosus (SLE). During hospitalization, the patient was characterized by recurrent high-grade fever, petechiae and ecchymoses of abdominal skin, and pulmonary infection. Whole exon gene sequencing revealed decreased activity of natural killer cells. She received systematic treatment with Methylprednisolone, Etoposide, and anti-infective drugs. Intravenous immunoglobulin and plasmapheresis were applied when the condition was extremely acute and progressive. The patient recovered and did not present any relapse of the HLH for one year of follow-up.

CONCLUSION

The case showed sHLH, thrombotic microvascular, and infection in the whole course of the disease, which was rarely reported by now. The treatment of the patient emphasizes that early recognition and treatment of sHLH in SLE patients was of utmost importance to improve the prognosis and survival rate of patients.

Epstein-Barr virus-associated haemophagocytic lymphohistiocytosis complicated by neurological involvement in a patient with dermatomyositis: A case report and literature review

Haemophagocytic lymphohistiocytosis (HLH) is an extremely high mortality condition that can occur at any age and lacks specific diagnostic characteristics. Despite its rarity, HLH is increasingly alarming because of the high mortality rate. It is a systemic hyperinflammatory immune response syndrome associated with abnormal activation of T cells and macrophages, which may be caused by genetic mutations or acquired factors, such as infection, autoimmune condition, and malignancy. Here, we present a fatal case of Epstein-Barr virus-associated HLH complicated by neurological involvement in a patient with dermatomyositis. We describe and discuss the pathological features, classification, and effective treatment options of HLH and discuss separately the special characteristics of Epstein-Barr virus-associated HLH and dermatomyositis-associated HLH.