Patterns of antidepressant medication supply were examined. The rate of persons supplied PBS-subsidised antidepressant medications ranged from 63.5 per quarter per 1,000 total population in the December 2004 quarter to 59.3 per quarter per 1,000 in the December 2009 quarter (see figure 8.1). Scripts for PBS–subsidised antidepressant medications ranged from 170.3 per 1,000 total population to 166.4 per 1,000 total population over the same period (see figure 8.2). Figure 8.1 and figure 8.2 also show the rate of persons using Better Access services after the initiative was introduced in November 2006.

Analyses were undertaken to examine whether patterns of antidepressant supply had changed since the introduction of Better Access. As Better Access was introduced part–way through the December 2006 quarter, the following analyses exclude the December 2006 quarter. By doing this, analyses could be undertaken to compare two full years pre–Better Access and three full years post– Better Access, which has the advantage of minimising the influence of seasonal patterns.j

In order to address whether Better Access has resulted in a change in demand for these medications, analyses must to assess whether any apparent decrease in antidepressant supply is modified after the introduction of Better Access. To achieve this, a series of negative binomial regression analyses (see section 2.3.3 for more information) were used to estimate the trends in medication supply for the pre–Better Access period and the post–Better Access period, and to determine whether a change in trend had occurred between these two time periods. Table 8.1 presents the results of these analyses for PBS–subsidised antidepressant medication supply. The results suggest that the rate of persons using antidepressant medications decreased by 1.1% per quarter (RR = 0.989; P = 0.010) in the two years before the introduction of Better Access but increased by 0.9% per quarter in the three years after the introduction of Better Access (RR = 1.009; P = <0.001). The ratio of the post–Better Access trend to the pre–Better Access trend was statistically significant (RR = 1.020; P = <0.001), indicating a significant change in trend. That is, the small but significant decline in antidepressant supply occurring during the two year prior to Better Access, was reversed in the period following the introduction of Better Access.

Table 8.2 shows that prior to the introduction of Better Access, the rate of scripts supplied was stable. Following the introduction of Better Access, there was a significant increase in scripts supplied for antidepressants. The change in trend was statistically significant.

Patterns of anxiolytic medication supply were examined using the same procedures as for antidepressant medications. The rate of persons supplied anxiolytic medications ranged from 17.9 per quarter per 1,000 total population in the December 2004 quarter to 16.1 per quarter per 1,000 total population in the December 2009 quarter (see figure 8.3). Scripts for anxiolytic medications ranged from 44.2/1,000 per quarter to 39.5/1,000 per quarter over the same period (see figure 8.4). Figure 8.3 and figure 8.4 also show the rate of persons using Better Access services after the initiative was introduced in November 2006.

Table 8.2 shows the results of the comparison of the trends in PBS–subsidised anxiolytic medication supply for the pre– and post–Better Access periods. In contrast to the findings for antidepressants, there was no significant change in trend for supply of anxiolytic medications, with time trends stable across the pre– and post– Better Access periods.

It is important to acknowledge a major limitation of the previous analyses, which is that data from the PBS alone may be misleading because it only records subsidised medicines. It is estimated that approximately 75% of antidepressant medication prescriptions and 73% of anxiolytic medication prescriptions dispensed by pharmacies are recorded on the PBS.49 Over-the–counter medications, and non–subsidised medications (e.g., where the entire cost of the medication is covered by the consumers' co–payment) are not captured. Further, when particular medications recorded on the PBS fall below the payment threshold, they are no longer recorded by the PBS. This is particularly important for the antidepressant group of medications because several commonly prescribed medicines came off patent in the period shortly preceding Better Access commencement (e.g., fluoxetine in 2004 and sertraline in 2006).50 As a result new generic products were released, the cost of which fell below the PBS payment threshold. This is likely to explain the apparent decreasing trend in the rate of persons using antidepressant medications in the two years prior to the introduction of Better Access.Top of page

Figure 8.1 Persons using Better Access items and PBS–subsidised antidepressant medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).

Text equivalent below for Figure 8.1 Persons using Better Access items and PBS–subsidised antidepressant medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).

Text version of Figure 8.1

Figures in this description are approximate as they have been read from the graph.
Persons using Better Access MBS items
Rate per 1,000 population
Persons supplied antidepressant medications
Rate per 1,000 population
December 04
-
64
March 05
-
59
June 05
-
61
September 05
-
61
December 05
-
60
March 06
-
56
June 06
-
57
September 06
-
59
December 06
5
60
March 07
10
50
June 07
14
53
September 07
15
54
December 07
16
55
March 08
16.5
50
June 08
17
53
September 08
18
54
December 08
19
55
March 09
20
53
June 09
22
55
September 09
23
57
December 09
22.5
60
Top of page

Figure 8.2 Persons using Better Access services and scripts supplied for PBS–subsidised antidepressant medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).


Text equivalent below for Figure 8.2 Persons using Better Access services and scripts supplied for PBS–subsidised antidepressant medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).

Text version of Figure 8.2

Figures in this description are approximate as they have been read from the graph.
Better Access services used
Rate per 1,000 population
Scripts for antidepressant medications supplied
Rate per 1,000 population
December 04
-
170
March 05
-
140
June 05
-
155
September 05
-
152
December 05
-
160
March 06
-
135
June 06
-
145
September 06
-
152
December 06
10
160
March 07
22
125
June 07
32
135
September 07
37
136
December 07
38
152
March 08
39
125
June 08
45
135
September 08
46
140
December 08
46
155
March 09
50
130
June 09
55
145
September 09
57
150
December 09
56
166
Top of page

Figure 8.3 Persons using Better Access items and PBS–subsidised anxiolytic medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population)

Text equivalent below for Figure 8.3 Persons using Better Access items and PBS–subsidised anxiolytic medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population)

Text version of Figure 8.3

Figures in this description are approximate as they have been read from the graph.
Persons using Better Access MBS items
Rate per 1,000 population
Persons supplied anxiolytic medications
Rate per 1,000 population
December 04
-
19
March 05
-
15.5
June 05
-
16.5
September 05
-
17.5
December 05
-
18.5
March 06
-
15
June 06
-
16
September 06
-
17
December 06
5
18
March 07
10
15
June 07
13
16
September 07
14
17
December 07
15
18
March 08
15.5
14.5
June 08
18
15.5
September 08
19
16.5
December 08
19.5
17.5
March 09
20.5
14.5
June 09
21
15.5
September 09
23
16.5
December 09
22
17.5
Top of page

Figure 8.4 Persons using Better Access services and scripts supplied for anxiolytic medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).

Text equivalent below for Figure 8.4 Persons using Better Access services and scripts supplied for anxiolytic medications, December 2004 quarter to December 2009 quarter (rate per 1,000 population).

Text version of Figure 8.4

Figures in this description are approximate as they have been read from the graph.
Better Access services used
Rate per 1,000 population
Scripts for anxiolytic medications supplied
Rate per 1,000 population
December 04
-
45
March 05
-
35
June 05
-
40
September 05
-
42
December 05
-
43
March 06
-
35
June 06
-
40
September 06
-
42
December 06
10
43
March 07
25
35
June 07
30
36
September 07
35
38
December 07
36
40
March 08
39
34
June 08
45
35
September 08
46
36
December 08
47
40
March 09
50
32
June 09
55
-
September 09
56
-
December 09
55
-
Top of page

Table 8.1 Estimated change in trends for uptake of PBS–subsidised antidepressant medications, before and after the introduction of Better Access

Antidepressant medication useTrend pre-Better Access
RR (95 % CI)
PTrend post-Better Access
RR (95% CI)
PRatio of trendsa
RR (95% CI)
P
Persons using medication
0.989 (0.981-0.997)
0.010
1.009 (1.004-1.014)
<0.001
1.020 (1.010-1.030)
<0.001
scripts supplied
0.989 (0.970-1.008)
0.251
1.015 (1.004-1.025)
0.006
1.026 (1.004-1.049)
0.020

2004 through 2008 figures have regard to all claims processed up to and including August 2009; 2009 figures have regard to all claims processed up to and including June 2010.
RR, rate ratio; CI, confidence interval. Data exclude the December 2006 quarter.
a The ratio of the post–Better Access trend to the pre–Better Access trend.

Table 8.2 Estimated change in trends for uptake of PBS–subsidised anxiolytic medications, before and after the introduction of Better Access

Anxiolytic medication useTrend pre-Better Access
RR (95 % CI)
PTrend post-Better Access
RR (95% CI)
PRatio of trendsa
RR (95% CI)
P
Persons using medication
0.991 (0.978-1.005)
0.206
1.000 (0.994-1.006)
0.943
1.009 (0.995-1.023)
0.202
scripts supplied
0.992 (0.974-1.011)
0.402
1.000 (0.992-1.008)
0.983
1.008 (0.989-1.027)
0.420

2004 through 2008 figures have regard to all claims processed up to and including August 2009; 2009 figures have regard to all claims processed up to and including June 2010.
RR, rate ratio; CI, confidence interval. Data exclude the December 2006 quarter.
a The ratio of the post–Better Access trend to the pre–Better Access trend.

Footnotes

j As shown in figure 8.1 and figure 8.2 medication supply is higher in the latter part of each year. This peak is due to the safety net provisions in the PBS. "These provisions were introduced to ensure patients with multiple medical conditions, who genuinely need a number of medications, are not prevented financially from obtaining them. Once the out–of pocket threshold safety net level is reached, prescriptions on the scheme are either free, or available at greatly reduced copayment amount. The safety met period is the calendar year, and the highs and lows are due to stockpiling of medication once the safety net level is reached."48. Australian Government Department of Health & Ageing. Australian Statistics on Medicines. Canberra: Commonwealth of Australia; 2009. (p.12).