HIV and health economics: where next? Dr Mike Youle

Dr Mike Youle MB ChB Director of HIV Clinical Research, Royal Free Hospital, London

The HIV epidemic, which is well into its second decade, has left a lasting impression on healthcare in the UK. Changes in perspectives on patients' involvement in their own care, the rapid expansion of the numbers infected (although luckily not as great as some other countries in Europe) and the increase in available therapies have all played their role in this.

From 1986, when zidovudine (AZT) became the first available antiretroviral agent, the costs of drug therapy and the continuing care of patients who need to be hospitalised have produced an increasing burden on most health authorities. Due to the epidemiology of the epidemic, this has been concentrated largely in urban centres - and specifically in North London.

Early efforts

In the early part of the epidemic, physicians' energies were largely taken up with concentrating on the expanding range of presentations and unusual conditions seen in HIV, learning how to treat them effectively and conducting studies of putative anti-HIV agents. However, things have now changed.

There has been a dramatic decrease in morbidity and mortality since the introduction in late 1995 of protease inhibitors and combination antiretroviral therapies. Death rates have plummeted and numbers of patients willing to test for the presence of HIV have increased, thereby swelling the numbers being cared for. The increasing complexity of care has led to longer patient visits and the need for constant monitoring has increased outpatient load. Meanwhile inpatient numbers have declined.

Whether this situation will continue shall be determined, to a degree, by the quality of care delivered to patients and by the ongoing effects of drugs in suppressing HIV replication. Further agents are in the pipeline, and the possibility of immune stimulation with agents such as interleukin-2 are future options that may bring benefits and will certainly incur costs.

Cost assessments required

Clearly, the time has come not only for clinical and epidemiological assessment of the benefits of therapy but also of their costs to the NHS. Within a socialised system, which requires allocation of monies to a problem in a measured manner, it is vital to have appropriate tools to measure economic outcomes.

To date there has been a paucity of investigation and research into issues surrounding health economics in Britain. Much more work is being conducted in the USA, where the financial model of healthcare is more structured. Economic information is acutely needed in the UK, given the impact of drug innovation on annual budgets and the already expanding overspend of most HIV drug units.

Modelling approaches have been utilised until now, since there has been a shortage of prospective survival data with new therapies. All modelling studies have limitations, but they are likely to be required for the foreseeable future, since most clinical trials are stopped as soon as differences in surrogate markers are observed. Moreover, the size of studies available are likely to remain too small to yield useful resource-utilisation data for economic analysis.

Another difficulty in assessing the issue is the lack of cost data for procedures and other resource-utilisation in both hospital and community. Additionally, since many of the benefits of therapy are indirect (such as improvements in quality of life and economic capacity), problems arise when purely health-related benefits are evaluated. Certainly patients' reduced need for community care and increased willingness to re-enter the job market has an economic impact that is rarely assessed when considering the benefits of new therapy.

Several studies have assessed the cost effectiveness of HIV monotherapy treatment . Cost per life-year saved has varied from £30-40,000, depending on the assumptions made and the country in which the research was conducted. Meanwhile, for combination therapy , the incremental cost-effectiveness ratio has been assessed at between £6-10,000. This compares very favourably with the other interventions, with almost all assessed interventions costing more than £15,000 per life-year saved (other than counselling for smoking cessation).

Collaborating for success

Health economics are currently being built into most clinical studies, along with assessment of quality of life. Outside the UK there is now a regulatory requirement to build economic assessment into large Phase 3 clinical trials - indeed, in the USA it is mandatory. However, population- and unit-based data will provide more realistic estimates of costs and, to that end, a collaboration, the HIV Health Economics Collaboration (HHC), has been established between Brighton, Chelsea & Westminster and the Royal Free HIV centres. HHC includes pharmaceutical industry participation and external epidemiological and health economics advice. A project to expand and make compatible the three databases and a study of the relative benefits of multi-antiretrovirals are currently underway.

Health economics is a growth area within the health service and is a vital component for the planning and provision of quality care. Clearly, the next century will see a revolution in the methods by which we assess the costs of healthcare and the way improvements can be delivered at best price for both the system and the individual patient.

Further reading

  1. Chancellor JV, Hill AM, Sabin CA, Simpson KN, Youle M. Modelling the cost effectiveness of lamivudine/zidovudine combination therapy in HIV infection. Pharmacoeconom 1997; 12: 54-66.
  2. Moore RD, Chaisson RE. Cost-utility analysis of prophylactic treatment with oral ganciclovir for cytomegalovirus retinitis. JAIDS 1997; 16: 15-21.
  3. Holtgrave DR, Pinkerton SD. Updates of cost illness and quality of life estimates for use in economic evaluations of HIV prevention programs. JAIDS 1997; 16: 54-62.
  4. Mouton Y, Alfandari S, Vallet M et al . Impact of protease inhibitors on AIDS-defining events and hospitalisations in 10 French AIDS reference centres. AIDS 1997; 11: F101-105.