Marinho et al developed an equation for predicting the 6-minute walking distance (6MWD) for a Brazilian adult with sickle cell disease. The authors are from the State University of Rio de Janeiro and Augusto Motto University Center in Brazil.

Patient selection: Brazilian adult with sickle cell anemia



(1) hemoglobin in g/dL

(2) FVC (forced vital capacity) as percent of predicted (from 0 to 100)

(3) tricuspid regurgitant velocity (TRV) in meters per second (m/s)

(4) acute chest syndrome (ACS, with 0 if absent and 1 if present)


6MWD as percent of predicted =

= (7.46 * (hemoglobin)) + (0.296 * (percent of predicted FVC)) - (6.102 * (TRV)) - (2.148 * (points for ACS)) + 8.11


The equation reflects factors that negatively affect the six-minute walking distance:

(1) anemia

(2) reduced pulmonary function

(3) elevated TRV (>= 2.5 m/s)

(4) acute chest syndrome (ACS)

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