Clinical prediction model for differentiation of disseminated Histoplasma capsulatum and Mycobacterium avium complex infections in febrile patients with AIDS.
BACKGROUND
Disseminated infection with Histoplasma capsulatum and Mycobacterium avium complex (MAC) in patients with AIDS are frequently difficult to distinguish clinically.


METHODS
We retrospectively compared demographic information, other opportunistic infections, medications, symptoms, physical examination findings and laboratory parameters at the time of hospital presentation for 32 patients with culture documented disseminated histoplasmosis and 58 patients with disseminated MAC infection.


RESULTS
Positive predictors of histoplasma infection by univariate analysis included lactate dehydrogenase level, white blood cell (WBC) count, platelet count, alkaline phosphatase level, and CD4 cell count. By multivariate logistic regression analysis, those characteristics that remained significant included a lactate dehydrogenase value > or =500 U/L (risk ratio [RR], 42; 95% confidence interval [CI], 18.53-97.5; p < .001), alkaline phosphatase < or =300 U/L (RR, 9.35; 95% CI, 2.61-33.48; p = .008), WBC < or =4.5 x 10(6)/L (RR, 21.29; 95% CI, 6.79-66.75; p = .008), and CD4 cell count (RR, 0.958; 95% CI, 0.946-0.971; p = .001).


CONCLUSIONS
A predictive model for distinguishing disseminated histoplasmosis from MAC infection was developed using lactate dehydrogenase and alkaline phosphatase levels as well as WBC count. This model had a sensitivity of 83%, a specificity of 91%, and a misclassification rate of 13%.
Graviss
E A
EA
Section of Infectious Diseases, Veterans Affairs Medical Center, Houston, Texas 77030-4211, USA.
Vanden Heuvel
E A
EA
Lacke
C E
CE
Spindel
S A
SA
White
A C
AC
Hamill
R J
RJ
D017088:AIDS-Related Opportunistic Infections / Q000503:physiopathology*; D000328:Adult; D000469:Alkaline Phosphatase; D018791:CD4 Lymphocyte Count; D005260:Female; D005334:Fever / Q000503:physiopathology*; D006658:Histoplasma; D006660:Histoplasmosis / Q000503:physiopathology*; D006801:Humans; D007770:L-Lactate Dehydrogenase; D007958:Leukocyte Count; D008297:Male; D008954:Models, Biological; D015269:Mycobacterium avium Complex; D015270:Mycobacterium avium-intracellulare Infection / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies
D007770:L-Lactate Dehydrogenase; D000469:Alkaline Phosphatase