Table 2.

Changes in attendance rate (primary outcome) after the introduction of referral management in each group: linear regression and ARIMA regression with autocorrelation correction

Group	Referral-management approach	Mean attendance rate before start of referral management per 1000 persons per month	Mean attendance rate after start of referral management per 1000 persons per month	Change in attendance rate (95% CI) associated with start of referral management per 1000 persons per montha	Change in attendance rate (95% CI) associated with start of referral management (ARIMA) per 1000 persons per montha
1	Internal peer review	14.9	15.6	0.76c (0.12 to 1.40)	0.72 (–0.18 to 1.61)
2	Internal peer review	14.0	15.2	1.20c (0.60 to 1.80)	0.80 (–0.11 to 1.71)
3	Referral-management centre	15.1	16.1	1.10c (0.67 to 1.53)	1.05c (0.46 to 1.64)
4b	Referral-management centre	14.3	14.6	0.41c (0.02 to 0.79)
5	Referral-management centre	17.0	17.3	0.27 (–0.36 to 0.90)	0.27 (–0.37 to 0.90)

^aMay not equal the difference between mean attendance rate before and after start of referral management because of the effect of the incremental introduction of referral management.

^bAutocorrelation was not significant in group 4; therefore, an ARIMA model was not used in this group.

^cStatistically significant at 5% level.