Table 1.

Multivariable Model of Prospective Rates of ACS and Pain in 70 Children with SCA

Covariate	IRR	95% CI	P Value
Multivariable model of prospective rates of ACS
Male sex	0.53	0.30–0.93	0.027
History of an ACS episode prior to 4 yr of age	2.88	1.66–4.99	<0.001
History of wheezing leading to shortness of breath	1.50	0.76–2.96	0.24
Log methacholine dose–response slope	1.11	0.98–1.27	0.108
Multivariable model of prospective rates of vasoocclusive pain episodes
Age	1.12	1.04–1.20	0.004
White blood cell count	1.00	0.93–1.08	0.991
Log methacholine dose–response slope	0.97	0.85–1.11	0.654

Definition of abbreviations: ACS = acute chest syndrome; CI = confidence interval; IRR = incidence rate ratio; SCA = sickle cell anemia.

Negative binomial regression models with adjustment for overdispersion, using robust SEs. Two-tailed significance values are shown.