Selective reimbursement policies can have a palpable impact on prescribing trends in relatively high-volume, high-cost disease categories, new research from Norway suggests. They can achieve this, moreover, without compromising treatment goals. Whether the restrictions actually save much money, though – at least in the short term – is more open to question.

In a study commissioned by Norway’s Ministry of Health and Care Services, researchers from the Norwegian Knowledge Centre for the Health Services in Oslo and the Health Services Research Unit at the University of Aberdeen in Scotland analysed prescribing data for antihypertensives before and after the implementation of a new reimbursement rule in March 2004.

Designed to cut public expenditure on antihypertensives, which accounted for around 10% of all registered drug sales in Norway in 2003, the new rule made reimbursement of drug costs for uncomplicated hypertension conditional on the choice of a thiazide as first-line therapy, unless there were medical reasons for selecting an alternative drug. While there is some debate in Norway over whether the thiazides are as effective as other antihypertensives at controlling blood pressure, their prices are one-tenth those of many non-thiazide therapies, note the authors in a paper published online by PLoS Medicine.

The study included all patients started on antihypertensive medication in 61 general practices in and around Oslo, Norway. During the baseline period – before the Norwegian parliament passed the reimbursement regulation in late 2003 – the proportion of thiazide prescriptions among all prescriptions for patients started on treatment for uncomplicated hypertension was consistently around 10%. Thiazide prescribing rose sharply during the transition period for the new regulation (December 2003 to February 2004) and stabilised at around 25% after the measure came into effect.

There was no statistically significant impact on the achievement of treatment goals over these periods – in fact, the proportion of patients hitting treatment targets was slightly higher (58.4% versus 56.6%) after the new rule came into force, while prescribing of a second antihypertensive within four months of starting treatment was slightly lower (21.8% versus 24.0%). But the estimated savings on drug expenditure in the first 12 months post-intervention were just NKr4.8 million (€0.61 million) or NKr1.06 per inhabitant of Norway, out of a total annual spend of NKr1,500 million or NKr330 per inhabitant on antihypertensives nationwide.

Impact dulled

The financial impact was probably dulled by price modifications for a number of antihypertensives in the year following the introduction of the regulation, the authors pointed out. For example, the prices of several ACE-inhibitors dropped “substantially” during the study period, while prices of some thiazides increased. The economic analysis used 2003 prices for both study periods (i.e., pre- and post-intervention); without the observed price changes the estimated savings would have more or less doubled, the researchers said.

The bulk of the savings from the new reimbursement rule can be expected after the first year, as an increasing number of patients are started on thiazides, they believe. Assuming prescribing patterns and drug prices remained stable from the post-intervention period onwards, the researchers forecast annual savings of around NKR37 million after five years, equivalent to NKr8.12 per inhabitant. However, they cautioned, “countermeasures by pharmaceutical companies can be anticipated and could influence prescribing patterns and drug costs, thus reducing the potential savings.”

Non-compliance

Moreover, the authors noted, even after the regulation took effect, non-thiazides were still being prescribed in 75% of all new cases of uncomplicated hypertension. “It is highly unlikely that sound medical reasoning can explain this high degree of non-compliance among prescribing physicians,” they commented. Suggested culprits included controversy in the medical community about the appropriateness of thiazides as first-line therapy for hypertension, a marketing push behind more expensive antihypertensives and the possible inclusion in the analysis of some patients who were not covered by the new regulation.

On top of this, adherence to the new rule was monitored only minimally in the year after its introduction and there were no penalties for non-adherence. Furthermore, the only requirement for reimbursement of alternative antihypertensives was a note in the medical record stating why a thiazide was not appropriate. Limiting access to exemptions might have enhanced the effectiveness of the regulation but it would also have increased administrative costs and resistance from stakeholder groups, the researchers said.