Table 2.

Bivariate analysis of binary variables and association with AVN

Variable	OR	95% CI
SS genotype	1.43	0.72–2.83
High utilizer (≥4 visits/y)	4.28***	1.88–9.76
Cholecystectomy	1.86	0.97–3.56
ACS	3.12***	1.41–6.93
Pneumonia	3.20*	1.17–8.73
CVA	0.80	0.32–2.03
Pulmonary embolism	1.00	0.35–2.85
Leg ulcer	1.86	0.74–4.65
DVT	2.11	0.96–4.67
Retinopathy	1.47	0.79–2.72
Chronic kidney disease	0.59	0.27–1.28
Ever used hydroxyurea	2.23*	1.16–4.29
Ever received long-term transfusion	2.33*	1.19–4.60
Psychiatric illness	1.43	0.72–2.83
Substance use	0.94	0.49–1.83

ACS, acute chest syndrome; AVN, avascular necrosis; CI, confidence interval; CVA, cerebrovascular accident; DVT, deep vein thrombosis; OR, odds ratio; SS, Sβ⁰ thalassemia.

^*P ≤ 0.05;

^**P ≤ 0.01;

^***P ≤ 0.005.