Time trends in antiretroviral treatment use in Australia, 1997-2000

Objectives: To assess how developing knowledge surrounding combination antiretroviral treatment for people living with HIV infection since mid-1996 has altered how drugs are used in Australia. Methods: Time trends in use of antiretroviral treatment were calculated on patients recruited to the Australian HIV Observational Database. For each six-month period, patients were on one or more antiretroviral drugs for at least two weeks. Other patients were in the no-treatment group. Patients receiving antiretrovirals for more than two weeks were allocated to the category of treatment (mono, double or triple-plus therapy) they received for the longest period. Results: 1476 patients were recruited by September 2000. Of patients currently receiving antiretroviral therapy, 32 per cent took three or more antiretrovirals including an HIV protease inhibitor (PI) and 27 per cent took triple-plus therapy including a nonnucleoside reverse transcriptase inhibitor (NNRTI). The proportion of patients receiving regimens containing stavudine (D4T) decreased from 60 per cent in January to June 1999 to 46 per cent in July to September 2000. The proportion of patients receiving zidovudine (AZT) increased slightly from 26 per cent to 30 per cent. The addition of ritonavir to PI-containing regimens increased from 12 per cent in January to June 1999 to 33 per cent in July to September 2000. The proportion of patients ceasing treatment also increased. By July to September 2000, 10 per cent of patients had ceased treatment for more than three months. Conclusion: Antiretroviral treatment use has changed in Australia. Whether these changes are associated with improved clinical outcomes remains uncertain.