Table 1.

Risk Factors for RSV Rehospitalization Among Infants Discharged From the NICU Before the RSV Season, Kaiser Permanente Medical Care Program (Northern California), 1992–1996

Risk Factor	Total n	Hospitalized for RSV (%)
Gestation, wk
23–32	438	7.3^*,^†
23–28	99	11.1^‡
29–32	339	6.2
33–36^§	1283	1.8
Birth weight, g
<1500	264	8.7^*
≥1500	1457	2.2
Oxygen therapy, d
<28	1597	2.3
≥28	124	14.5^*
Assisted ventilation, d
<14 days	1608	2.4
≥14 days	113	14.2^*
Date of NICU discharge
December–August^‖	1238	2.2
September–November	483	5.8^*
Maternal race
White	1065	3.2
Asian	220	2.3
Black	142	2.1
Latino	231	4.3
Sex
Female	762	3.3
Male	959	3.1
Multiple gestation
No	1334	2.9
Yes	387	4.1

↵* P ≤ .001.
↵† Versus 33 to 36 weeks.
↵‡ P = .1 versus 29 to 32 weeks.
↵§ No difference in hospitalization risk was seen when only infants born at 33 to 35 weeks were included in this group.
↵‖ Within the group of infants discharged between December and August, risk of RSV hospitalization during the subsequent RSV season was uniform.