Background ‘Amedeo di Savoia’ Hospital is the regional centre in Piedmont for HIV infection diagnosis and treatment. A multidisciplinary team, Infectiologists, Pharmacists, Nurses, and Psychologists are working to optimise the clinical and therapeutic path of HIV-positive patients, to increase the efficacy and tolerability of HAART and to reduce its costs.

Purpose To focus on a process to measure the adherence to, and appropriateness of, HAART treatment in order to identify ways to increase the efficacy of the treatment.

Materials and methods The analysis was performed with 2094 HIV-positive patients (110 of whom were treatment-naive), whose HAART treatment was dispensed every 2 months, over a period of 22 months (1/11/2009-31/08/2011). The authors assessed each switch in treatment in terms of reasons and cost variations. Appropriateness was assessed by comparing prescriptions with registered indications. Adherence was calculated by measuring the ‘pharmacy refill’ as: days' supplies between refill dates/(duration of interval + 60 days) x 100.

Results Antiretroviral treatment switches were made in 322 patients because of adverse drug reactions, treatment failure or simplification:

• ▶ In 45% of cases treatment switch led to a saving (25% of switches saving more than 20%)

• ▶ In 55% the cost of treatment increased (of which 33% by more than 20%)

• ▶ 118 (0.06%) patients received non-appropriate HAART prescriptions compared to registered indications.

These prescriptions are now being discussed in Local Pharmaceutical Committees in order to create specific protocols.

Adherence estimated is measured on:

• ▶ 1.738 (83%) patients in treatment with NNRTI or NRTI: 54% are patients with >95% adherence, only 1% with <40% adherence;

• ▶ 1196 (57%) treated with PIs: 46% are patients with >95% adherence, only 2% with <40% adherence.

Conclusions Assessing the result of switching treatment has demonstrated no substantial variations in terms of costs; adherence results are in line with literature data. These studies together with appropriateness analysis are important to verify the effectiveness of HAART.