The risk for a child with sickle cell disease developing severe complications can be predicted based on 3 clinical parameters occurring by the age of 2 years. This can help identify children who may benefit from more intensive therapy and monitoring. The investigators were associated with the Cooperative Study of Sickle Cell Disease and represented several American medical centers.
Severe complications from sickle cell disease include:
(1) death
(2) stroke
(3) one or more episodes of acute chest syndrome
(4) two or more painful events in 1 year
Factors found before the age of 2 that were associated with severe complications:
(1) dactylitis (pain and tenderness in the hands and feet) by the age of 1
(2) anemia (with hemoglobin < 7 g/dL)
(3) leukocytosis in the absence of infection
|
Parameter |
Finding |
Relative Risk for Severe Complication |
|---|---|---|
|
dactylitis before 1 year of age |
no |
1.00 |
|
|
yes |
2.55 |
|
leukocyte count |
for each 10 unit increase |
1.80 |
|
hemoglobin |
>= 7 g/dL |
1.00 |
|
|
< 7 g/dL |
2.47 |
Table 3, page 86.
The risk for severe complication based on combinations of WBC count, anemia and/or dactylitis is given in Figure 1, page 86. This data was extracted into the following table.
|
|
Risk of Severe Complications |
|||
|
WBC in thousands |
no anemia |
no anemia |
anemia |
anemia |
|
5 |
0.057 |
0.138 |
0.162 |
0.333 |
|
7.5 |
0.067 |
0.160 |
0.186 |
0.381 |
|
10 |
0.079 |
0.186 |
0.215 |
0.426 |
|
12.5 |
0.095 |
0.22 |
0.254 |
0.477 |
|
15 |
0.113 |
0.255 |
0.290 |
0.523 |
|
17.5 |
0.135 |
0.295 |
0.334 |
0.576 |
|
20 |
0.156 |
0.333 |
0.373 |
0.619 |
|
22.5 |
0.183 |
0.378 |
0.421 |
0.670 |
|
25 |
0.215 |
0.421 |
0.466 |
0.707 |
|
27.5 |
0.250 |
0.470 |
0.517 |
0.750 |
|
30 |
0.285 |
0.52 |
0.568 |
0.790 |
data extrapolated from Figure 1, page 86
The following equations were used to approximate the data in JMP.
(1) no anemia and no dactylitis
risk of severe disease =
= (0.0002422 * ((WBC in thousands) ^2)) + (0.000609 * (WBC in thousands)) + 0.04865
(2) no anemia, dactylitis
risk of severe disease =
= (0.0002262 * ((WBC in thousands) ^2)) + (0.0075339 * (WBC in thousands)) + 0.0916545
(3) anemia, no dactylitis
risk of severe disease =
= (0.0002107 * ((WBC in thousands) ^2)) + (0.0090756 * (WBC in thousands)) + 0.10765
(4) anemia and dactylitis
risk of severe disease =
= (-0.000079 * ((WBC in thousands) ^2)) + (0.0212489 * (WBC in thousands)) + 0.225527
Purpose: To predict the risk of severe complications in a child with sickle cell disease using 3 clinical parameters.
Specialty: Hematology Oncology, Clinical Laboratory, Genetics
Objective: risk factors, laboratory tests, complications
ICD-10: D57,
