Patterns of medication use in Queensland Australia and the impact of a large copayment increase: an exploratory study

Balram, Peter (2015). Patterns of medication use in Queensland Australia and the impact of a large copayment increase: an exploratory study PhD Thesis, School of Nursing, Midwifery and Social Work, The University of Queensland. doi:10.14264/uql.2015.707

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Author Balram, Peter
Thesis Title Patterns of medication use in Queensland Australia and the impact of a large copayment increase: an exploratory study
School, Centre or Institute School of Nursing, Midwifery and Social Work
Institution The University of Queensland
DOI 10.14264/uql.2015.707
Publication date 2015-07-02
Thesis type PhD Thesis
Open Access Status Other
Supervisor Kathy Ahern
Remo Ostini
Lisa Nissen
Total pages 323
Language eng
Subjects 1117 Public Health and Health Services
1115 Pharmacology and Pharmaceutical Sciences
1199 Other Medical and Health Sciences
Formatted abstract
In Australia, the principal mechanism for facilitating access to medications is through the Pharmaceutical Benefits Scheme (PBS), which subsidises more than 90% of medications dispensed in Australia and contributes up to 80% of the cost of each medication. Although it ensures the availability of medication for the population, one unintended effect of this subsidisation is that it can encourage overconsumption and hoarding of medications, thereby contributing to waste and escalating healthcare costs.

Various policies to control expenditure and facilitate the efficient use of medications have been implemented, from the prescribing to the dispensing of the PBS medicine. An important policy influencing patient demand is cost sharing in the form of a patient copayment. Apart from reducing government expenditure, the copayment policy is intended to sensitise patients to the cost of the medication and to discourage overconsumption. However, some patients on multiple medications may respond to cost increases by modifying, reducing or ceasing their medication altogether. If these modifications affect the use of essential medications for the treatment of chronic diseases, then it may represent false economy in the long run for the government.

Aim
The aims of this research are to: 1) describe the pattern of PBS medication use in Queensland, Australia prior to an unusually large (21%) copayment increase; 2) establish whether the copayment increase resulted in a change in the overall purchasing of PBS medicines; and, 3) investigate changes according to characteristics of the patient and the therapeutic class of the medication.  

Methods
Data for this study were Federal Government records of PBS medications supplied to Queensland residents during 2004 and 2005. Randomly selected data on medications supplied to patients were provided from a claims database by Medicare Australia, an organisation which administers the PBS. A comparative analysis was conducted of the purchasing pattern in the calendar year 2004, just before a copayment rise came into effect, with the corresponding pattern in 2005.

The analysis included descriptive statistics of prescription use in 2004 and hypothesis testing of changes in prescription use in 2005 across patient and medication-related variables. In addition, an in-depth analysis was conducted for prescriptions for the management of the National Health Priority Area chronic diseases, and conditions of mental health, cardiovascular disease, diabetes, arthritis and asthma. Antibiotics were also included because they are a commonly used medication group independent of age and gender. The inclusion of antibiotics in the analysis for the thesis also facilitated an examination of the impact of cost on the purchasing of medications for the treatment of acute illness and provided a useful benchmark for the interpretation of medication use in patients with chronic conditions.

Results
The profile of medication use in 2004 indicated that while females purchased more medication overall than males, the difference narrowed with age. Although there was a pattern of increasing use with age for most medications, for some, such as antidepressants, anxiolytics and cholesterol lowering drugs, the increase started earlier, probably reflecting a change in focus to early detection and aggressive treatment. While multiple medication use increased with age and peaked in older patients, there was also an indication of a creep in multiple medication use in to younger age groups.

By contrast, the increase in patient copayment was associated with a change in the purchasing pattern of PBS medications in 2005. However, while the number of prescriptions overall increased in 2005, reductions in some purchases were observed in 2005. For example, patients who purchased an average of five or more prescription medications per month (representing major polypharmacy) in 2004 purchased significantly fewer medications in 2005.

Differences in the purchasing of anti-infective medications were used as a measure of changes in medication purchased for the treatment of acute illnesses. Results indicated that there was no significant change in the total number of anti-infective medications purchased between 2004 and 2005.

Analysis of purchasing patterns indicated that some patient groups reacted differently to the 21% copayment increase with complex relationships being identified. For example, prescriptions for the CVD group of medications increased significantly for males and females and across all age groups despite the increase in copayment. Patients who paid the general payment rate and used an average of two to four prescriptions per month (minor polypharmacy), significantly decreased their nervous system medication use following the copayment rise. Prescriptions for anxiolytics increased for females aged 25-64, patients affected by minor polypharmacy, and general patients, while prescriptions for non-steroidal anti-inflammatory drugs (NSAIDS) decreased significantly for both genders, all age groups, all levels of medication use and both payment categories (i.e. both concessional and general patients). Prescriptions for analgesics increased in 2005, but this was mainly related to an increase in the prescribing of opioid analgesics. The purchasing of non-opioid analgesics decreased significantly after the copayment increase in 2005.

Conclusion
This research suggests that the pattern of medication use is changing with the change in paradigm towards early detection, aggressive management and guideline-based treatment of chronic diseases. Multiple medication use is also on the rise and is extending into the younger age groups. Given the relationship between cost and medication adherence, general patients who pay a much higher copayment, and concessional patients taking multiple chronic disease medications could be at risk of nonadherence when unusually large copayment increases are implemented. Recommendations are: 1) phasing in large copayment increases over a longer timeframe rather than introducing increases all at once; 2) implementing systems to monitor the impact of large copayment increases on general patients, and concessional patients on multiple medications; 3) maintaining health provider incentives aimed at promoting quality use of medications; and 4) addressing polypharmacy by implementing guidelines for deprescribing, or extending the scope of home medicines review to include deprescribing.
Keyword Copayment
Cost sharing
Multiple medication use
Polypharmacy
Copayment change
PBS medication use
Medication use and level of insurance

Document type: Thesis
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Created: Sun, 28 Jun 2015, 16:34:13 EST by Peter Balram on behalf of School of Nursing, Midwifery and Social Work