The introduction of new biologic treatments has radically changed the management of Immune-mediated inflammatory diseases (IMID). Due to the high costs of the treatments a strong control and monitoring of claims databases could help decision makers to understand the consequences of their decisions.

The objective of the study was to identify the cohort of biologics treatment-naïve patients in the years 2011–2013 in the Lazio region (6 millions of inhabitants), in order to investigate the parameters influencing the biologic treatment expense at the regional level.

Patients were enrolled based on administrative databases of the Lazio region. Treatment-naïve patients were defined as subjects who did not have a prescription in the two years before the index prescription. Switcher patients were defined as those who had an Anatomical Therapeutic Chemical classification (ATC) prescription different than the one at enrolment, within one year of the index date. Treatment adherence was estimated as the number of doses actually prescribed as compared to the number indicated in the Summary of Product Characteristics (SPC).

From a total number of 10,120 patients treated with biologic drugs between 2011–2013 in the Lazio region, 2,929 were estimated as treatment-naïve patients (42 percent male). The most frequently used drugs were etanercept (31 percent), adalimumab (30 percent) and infliximab (17 percent). Considering the disease treatment distribution, 28.6 percent of patients were treated for rheumatoid arthritis, 25.5 percent for psoriatic arthritis, 16.4 percent for psoriasis and the remaining patients for other diseases. Some patients switched biologic therapy (367), of which 22.6 percent were within the first 120 days. Total mean adherence was estimated in 87.7 percent: 21.5 percent of patients showed a low adherence (SPC< 60 percent) while 18.1 percent were estimated as dose increase patients (SPC>110 percent), 11.4 percent for rheumatic diseases, 32.3 percent for dermatological diseases and 26.9 percent for inflammatory bowel disease.

The study provides a map of the current treatment settinga with biologics in the Lazio region considering the disease, adherence and prescribed treatments. A considerable number of treatment-naïve patients were identified (2,929), 12.5 percent of whom switched ATC within 1 year. Total mean adherence was estimated in 87.7 percent, low adherence occurred in 21.5 percent of patients, while dose-increase was in 18.1 percent.