Evaluation of the Better Access to Psychiatrists, Psychologists and GPs through the Medicare Benefits Schedule initiative: component B: an analysis of Medicare Benefits Schedule (MBS) and Pharmaceutical Benefits Scheme (PBS) administrative data

8.4 What is the relationship between Better Access uptake and demand for antidepressant and anxiolytic medications at a Divisional level?

Page last updated: August 2010

To examine the relationship between Better Access uptake and medications supplied, analyses were focused on the 2009 calendar year as these data are assumed to better represent established patterns of Better Access utilization than earlier years. Negative binomial regression analyses (see section 2.3.3 of this report for further information) were conducted separately for antidepressant and anxiolytic medications, to quantify the effect of Better Access uptake on medication supply within Divisions. The models used PBS–subsidised antidepressant or anxiolytic medication supply (persons using or scripts supplied, as appropriate), as the dependent variable, and adjusted for the size of the population in each Division by incorporating the logarithm of the population size as an offset term. The predictor was the rate of persons using Better Access services (per 1,000) in the Division.

Table 8.5 shows the summary statistics for PBS–subsidised antidepressant and anxiolytic medication supply and Better Access uptake for the 113 Divisions of General Practice in Australia in 2009.

Table 8.6 presents the results of the regression analyses for antidepressant medications. These show that the rate of persons supplied with antidepressant medications increased significantly as the percentage of the population in the Division using Better Access services increased. A similar effect was found for scripts supplied.

Table 8.7 presents the results of the regression analyses for anxiolytic medications. These show that the rate of persons supplied with anxiolytic medications increased significantly as the percentage of the population in the Division using Better Access services increased. A similar effect was found for scripts supplied. Interestingly, the effect was stronger for anxiolytic medications than for antidepressant medications.

These analyses were then repeated in order to examine persons using, and scripts supplied for, antidepressant and anxiolytic medications among concession card holders. Table 8.8 shows the summary statistics for PBS–subsidised antidepressant and anxiolytic medication supply and Better Access uptake for the 113 Divisions of General Practice in Australia in 2009.

Table 8.9 shows that the rate of persons supplied with antidepressant medications increased significantly as the percentage of the population in the Division using Better Access services increased. Results for concession card holders were the same as those for the total population.

Table 8.10 presents the results of the regression analyses for anxiolytic medications. These show that the rate of concession card holders supplied with anxiolytic medications increased significantly as the percentage of the population in the Division using Better Access services increased. A similar effect was found for scripts supplied. Again, the effect was stronger for anxiolytic medications than for antidepressant medications. Results for concession card holders were the same as those for the total population.Top of page

Table 8.5 Summary statistics for PBS–subsidised antidepressant and anxiolytic medication supply and Better Access uptake in 113 Divisions of General Practice in Australia, 2009

Division level measuresRangeMeanSD
Persons using antidepressant medications (per 1,000)
21.0-121.2
85.0
20.2
Antidepressant medication scripts supplied (per 1,000)
133.4-1,333.7
624.7
180.8
Persons using anxiolytic medications (per 1,000)
4.3-53.8
28.7
9.0
Anxiolytic medication scripts supplied (per 1,000)
17.1-285.5
147.8
52.8
Better Access users (per 1,000)
14.2-82.4
49.5
13.4

2009 PBS figures have regard to all claims processed up to and including June 2010. 2009 MBS figures have regard to all claims processed up to and including 30 April 2010.
SD, standard deviation.

Table 8.6 Negative binomial regression estimates of rate ratios with 95% CIs for PBS–subsidised antidepressant medication supply, 2009

RR95% CIP
Persons using antidepressant medications - Better Access users (per 1,000) in Division
1.005
1.002-1.009
0.004
Antidepressant medication scripts - Better Access users (per 1,000) in Division
1.005
1.001-1.010
0.029

2009 figures have regard to all claims processed up to and including June 2010.
RR, rate ratio; CI, confidence interval.

Table 8.7 Negative binomial regression estimates of rate ratios with 95% CIs for PBS–subsidised anxiolytic medication supply, 2009

RR95% CIP
Persons using anxiolytic medications - Better Access users (per 1,000) in Division
1.011
1.006-1.016
<0.001
Anxiolytic medication scripts - Better Access users (per 1,000) in Division
1.013
1.008-1.018
<0.001

2009 figures have regard to all claims processed up to and including June 2010. 2009 MBS figures have regard to all claims processed up to and including 30 April 2010.
RR, rate ratio; CI, confidence interval.

Table 8.8 Summary statistics for PBS–subsidised antidepressant and anxiolytic medication supply among concession card holders and Better Access uptake in 113 Divisions of General Practice in Australia, 2009

Division level measuresRangeMeanSD
Persons using antidepressant medications (per 1,000)
9.2-107.4
67.8
20.1
Antidepressant medication scripts supplied (per 1,000)
54.5-1,221.5
510.2
177.7
Persons using anxiolytic medications (per 1,000)
4.0-53.3
28.0
8.9
Anxiolytic medication scripts supplied (per 1,000)
15.6-282.4
145.5
52.6
Better Access users (per 1,000)
14.2-82.4
49.5
13.4

2009 figures have regard to all claims processed up to and including June 2010. 2009 MBS figures have regard to all claims processed up to and including 30 April 2010.
SD, standard deviation.

Top of page

Table 8.9 Negative binomial regression estimates of rate ratios with 95% CIs for PBS–subsidised antidepressant medication supply among concession card holders, 2009

RR95% CIP
Persons using antidepressant medications - Better Access users (per 1,000) in Division
1.006
1.001-1.011
0.020
Antidepressant medication scripts - Better Access users (per 1,000) in Division
1.005
1.000-1.011
0.060

2009 figures have regard to all claims processed up to and including June 2010. 2009 MBS figures have regard to all claims processed up to and including 30 April 2010.
RR, rate ratio; CI, confidence interval.

Table 8.10 Negative binomial regression estimates of rate ratios with 95% CIs for PBS–subsidised anxiolytic medication supply among concession card holders, 2009

RR95% CIP
Persons using anxiolytic medications - Better Access users (per 1,000) in Division
1.011
1.006-1.016
<0.001
Anxiolytic medication scripts - Better Access users (per,1000) in Division
1.013
1.007-1.019
<0.001

2009 figures have regard to all claims processed up to and including June 2010. 2009 MBS figures have regard to all claims processed up to and including 30 April 2010.
RR, rate ratio; CI, confidence interval.