Risk adjustment models for interhospital comparison of CS rates using Robson’s ten group classification system and other socio-demographic and clinical variables

Table 1 Crude and adjusted c-section RRs of hospitals

Hospital	n	Crude RR	p–value	Adj* RR	p–value	% variation†	Adj‡ RR	p–value	% variation†
A	2,377	1.39	<0.001	1.19	<0.001	−14.4	1.18	<0.001	−15.1
B	1,306	1.36	<0.001	1.25	<0.001	−8.1	1.26	<0.001	−7.4
C	935	1.05	0.428	1.00	0.908	−4.8	1.01	0.877	−3.8
D	344	1.27	0.006	1.35	<0.001	6.3	1.37	<0.001	7.9
E	1,468	1.34	<0.001	1.12	0.001	−16.4	1.14	<0.001	−14.9
F	1,677	1.41	<0.001	1.12	0.001	−20.6	1.09	0.006	−22.7
G	1,615	1.22	<0.001	1.08	0.026	−11.5	1.11	0.003	−9.0
H	459	1.71	<0.001	1.34	<0.001	−21.6	1.31	<0.001	−23.4
I	1,430	1.51	<0.001	1.26	<0.001	−16.6	1.21	<0.001	−19.9
J	2,096	1.39	<0.001	1.18	<0.001	−15.1	1.17	<0.001	−15.8
K	1,854	1.28	<0.001	1.25	<0.001	−2.3	1.24	<0.001	−3.1
L	4,389	1.02	0.550	0.90	<0.001	−11.8	0.90	<0.001	−11.8
M	603	1.82	<0.001	1.77	<0.001	−2.7	1.62	<0.001	−11.0
N	547	1.38	<0.001	1.13	0.044	−18.1	1.13	0.038	−18.1
O	1,923	1.02	0.616	1.09	0.019	6.9	1.05	0.188	2.9
P	2,120	1.38	<0.001	1.28	<0.001	−7.2	1.28	<0.001	−7.2
Q	4,377	1.14	<0.001	1.02	0.431	−10.5	1.03	0.261	−9.6
R	4,488	1.45	<0.001	1.29	<0.001	−11.0	1.29	<0.001	−11.0
S	598	2.73	<0.001	1.75	<0.001	−35.9	1.68	<0.001	−38.5
T	304	2.45	<0.001	1.76	<0.001	−28.2	1.72	<0.001	−29.8
U	4,591	1.58	<0.001	1.32	<0.001	−16.5	1.26	<0.001	−20.3
V	4,430	1.26	<0.001	1.06	0.009	−15.9	1.03	0.159	−18.3
W	5,635	1.34	<0.001	1.13	<0.001	−15.7	1.11	<0.001	−17.2
X	6,374	1.44	<0.001	1.35	<0.001	−6.2	1.31	<0.001	−9.0
Y	1,770	1.33	<0.001	1.25	<0.001	−6.0	1.23	<0.001	−7.5

* Adjusted for Robson class.
† The % variation is computed as (crude RR-adj RR)*100/crude RR.
‡ Adjusted for: age, citizenship, severe co-morbid illness of the mother, HIV, diabetes, hypertension, lung diseases, ante-partum haemorrhage/abruption placentae/placenta praevia, eclampsia/pre-eclampsia, foetal-pelvic disproportion/excessive development of the infant, foetal anomalies, RH-isoimmunisation, polyhydramnios, oligohydramnios, premature rupture of the membranes, problem of the amnios, congenital malformation, intrauterine growth retardation, post-maturity and macrosomia, Robson group.

ISSN: 1471-2393