Table 1: Case and control description and bivariate and multivariate analysis*.

VariablesCases (%)Controls (%) Bivariate analysis Multivariate analysis
Crude OR (95% CI) Adjusted OR (95% CI)

Age (years)
 0–42 (8)25 (33)1
 5–914 (59)21 (27)0.12 (0.02, 0.59) 0.009
 10–146 (25)15 (20)0.2 (0.04, 1.12)0.07
 15–192 (8)15 (20)0.6 (0.08, 4.72)0.63
Sex
 M13 (54)43 (57)1
 F11 (46)33 (43)1.1 (0.44, 2.77)0.84
Type of haemoglobin
 SS20 (83)45 (59)1
 S thal or SC 4 (17)31 (41)0.29 (0.09, 0.93)0.038
History of treatment by hydroxyurea
 Yes4 (17)11 (14)1
 No20 (83)65 (86)0.85 (0.24, 2.95)0.79
Duration of hospitalization (days)
 >7 14 (58)12 (16) 4.23 (2.64, 6.3) <0.013.69 (2.30–5.56)<0.01
 0–710 (42)64 (84)1
Age during the first symptoms
 1 year5 (21)34 (45)1
 Before 1 year19 (79)42 (55)3.08 (1.04, 9.09)0.04
History of >3 annual hospitalisations
 Yes19 (79)26 (34)7.31 (2.45, 21.8)<0.015.44 (3.59–8.21) 0.003
 No5 (21)50 (66)1
Basic haemoglobin level
 >8 g/dL3 (12)31 (41)1
 0–8 g/dL21 (88)45 (59)4.82 (1.32, 17.58)0.154.96 ( 1.29–27.34)0.04
Basic S haemoglobin level
 ≥80% 20 (83)39 (51)1
 <80%4 (17)37 (49)0.21 (0.07, 0.68) 0.009
Transthoracic echocardiography
 Normal15 (63)70 (95)1
 Abnormal9 (37)4 (5)10.5 (2.85, 38.65) <0.00113.77 (2.07–91.46)0.003
Transcranial echo-Doppler
 Normal19 (79)72 (97)1
 Abnormal5 (21)2 (3)9.47 (1.7, 52.69)0.01

Obtained using conditional logistic regression with indicator variables for nonbinary variables.
Bold fonts: OR (95% CI) of multivariate analysis.
Italic fonts: P-value of multivariate analysis.