Predictive model for diagnostic yield of bone marrow examination in patients with HIV infection having fever of unknown origin

Objective: Bone marrow examination is valuable for identifying the cause of fever of unknown origin (FUO) in HIV-infected patients. Based on the outcomes of bone marrow examination of patients with FUO, we aimed to develop a predictive model for identifying the factors that can increase the diagnostic yield of bone marrow examination. Design: For this retrospective cohort study, we enrolled HIV-infected patients, aged more than 15 years and diagnosed with FUO, at Songklanakarind Hospital in Southern Thailand, between January 2009 and December 2019. Methods: Evaluations were based on bone marrow aspiration, biopsy, and culture; any missing data were imputed with regression imputation. Results: Among the final 108 included patients, 44 (40.74%) showed positive bone marrow results. The diagnoses mainly comprised histoplasmosis, penicilliosis, and tuberculosis. Bone marrow examination led to treatment modifications in approximately 33% patients. Platelet count less than 150 000 cells/mu l, alkaline phosphatase (ALP) level at least 200 U/l, and no previous antibiotic treatment were significantly associated with higher diagnostic yields. The HIV bone marrow (HIVBM) model, comprising of spleen size, hematocrit (Hct), platelet count before bone marrow examination, ALP level at admission, and previous antibiotic treatment, was generated as a nomogram to predict the diagnostic yield of bone marrow examination in HIV-infected patients with FUO. Conclusion: The results of this study indicate that the HIVBM model can be used to predict the diagnostic yield of bone marrow examination, and therefore assist in clinical decision-making regarding bone marrow procedures, to be performed for identifying the origin of fever in HIV-infected patients.