Bilardi et al. BMC Public Health 2010, 10:70 http://www.biomedcentral.com/1471-2458/10/70 Table 1 Demographic characteristics of GPs at trial entry (n = 43)# Characteristic Number of GPs (N) Sex Male Female Age <35 years 35-44 years 45-54 years 55+ years Sessions worked each week <6 sessions 6-10 sessions 11+ sessions Years in general practice 0-10 years 11-20 years 21+ years GPs practice location by ARIA§ Regional/rural Metropolitan Postgraduate qualifications No Yes Interest in STIs Not interested Interested Aware of RACGP ‘Red Book’^ No Yes Intervention N (%) (95%CI) 20 9 (45) (25,67) 11 (55) (33,75) 3 (15) (5,38) 0 (0) (0,17) 13 (65) (42,83) 4 (20) (8,43) 9 (45) (25,67) 10 (50) (29,71) 1 (5) (0,29) 4 (20) (8,43) 6 (30) (14,53) 10 (50) (29,71) 4 (20) (8,43) 16 (80) (57,92) 8 (40) (21,63) 12 (60) (37,79) 2 (10) (2,33) 18 (90) (67,98) 2 (10) (2,33) 5* (23) (10,45) Control N (%) (95%CI) 23 11 (48) (28,68) 12 (52) (32,72) 2 (9) (2,30) 9 (39) (21,60) 8 (35) (18,56) 4 (17) (7,39) 7 (30) (15,52) 16 (70) (48,85) 0 (0) (0,15) 6 (26) (12,48) 9 (39) (21,60) 8 (35) (18,56) 5 (22) (9,43) 18 (78) (57,91) 0 (0) (0,15) 23 (100.0) (85,100) 2 (9) (2,30) 21 (91) (70,98) 2 (9) (2,30) 17 (77) (55,90) # Adjusted for clustering at GP level * One missing value ^RACGP ‘Guidelines for preventative activities in general practice 6th edition’ § Accessibility Remoteness Index of Australia - indexes of remoteness in Australia. chlamydia compared with 11.5% (95% CI: 4.6, 18.5) in the intervention group (Table 2). The median number of women tested in the control group in the pre-trial period was 6 (range: 0-29) and in the intervention group 8.5 (range 0-133). At this time, GPs in the intervention group were more than twice as likely to be testing women for chlamydia (OR: 2.2; 95% CI: 1.1, 4.4; p = 0.03). During the trial period, there was a non signifi- cant increase in testing in both the control group, 6.2% (95% CI: 4.2, 8.4) to 8.8% (95% CI: 4.8, 13.0) (p= 0.1), and in the intervention group, 11.5% (95% CI: 4.6, 18.5) to 13.4% (95% CI: 9.5, 17.5) (p = 0.4) (Table 2). The median number of women tested by GPs in the control group in the trial period was 5 (range: 0-32) and in the intervention group 8 (range: 0-49). The proportion of Page 5 of 9 women who tested positive for chlamydia did not change in the control group but decreased in the inter- vention group (p = 0.01) during the two time periods (Table 2). The interaction between the estimated effect of time period and intervention group showed that there was no difference in the proportion of women tested between the intervention and control group during the trial (OR = 0.9; 95% CI: 0.6,1.2) (Table 3). Barriers and facilitators to testing The most common barriers to increased chlamydia test- ing identified in GPs’ post trial questionnaire were: lack of time (29/43, 69%), difficulty remembering to suggest testing to patients (9/43, 21.4%) and patients’ lack of education and awareness about chlamydia testing (9/43, 21.4%). Anecdotally, many GPs noted that while they initially increased chlamydia testing at the beginning of the trial, as time progressed, they no longer remembered to offer testing, and/or forgot about the $5 incentive payment. The three main facilitators to increased testing identified by GPs were: financial incentives for GPs (17/ 42, 41%), patient education or awareness about testing (13/42, 31%) and computer prompts or reminders to test (11/42, 26%). Discussion In this study we found that offering GPs a $AUD5 test- ing payment did not increase testing for chlamydia. This was the first RCT to test incentive payments for chlamy- dia testing. Systematic reviews of RCT’s assessing the effectiveness of financial incentives to improve health care quality are limited, and often show mixed results [17,18,28]. Observational studies have found large incen- tive payments of £10-25 (approximately $AUD20-50) increased chlamydia testing significantly [19]. Our data suggest that a small incentive will not substantially improve chlamydia testing rates. Strengths and Limitations The major strength of this study was that it was the first RCT to our knowledge to examine the effect of provid- ing GPs with an incentive payment to increase chlamy- dia testing in general practice. Previous Australian studies aimed at increasing testing in general practice have examined the effectiveness of a variety of multi- faceted and singular method interventions, including the use of computer alerts [10], concurrent testing with pap smears [11] and online sexual health assessment tool referral [12]. Retention rates in the trial were very high, with a 96% response rate for testing data and question- naire data. The study provided a good representative sample of GPs across regional/rural and metropolitan Victoria.