Background Symptomatic Slow Acting Drugs for Osteoarthritis (SYSADOA) are recommended in many guidelines, but their actual use conditions are unclear, as they are considered nutriceutical products in most countries. In contrast, SYSADOAs are subsidized in the Spanish national health system, providing a unique opportunity to explore their utilization in the national OA population.

Objectives We explored a large database including electronic medical records and pharmacy invoice data from Catalonia (North-East Spain) to describe baseline characteristics of SYSADOA users when compared to users of the most commonly used drug for OA in our data (paracetamol).

Secondly, we estimated incidence of use of the three locally available oral SYSADOA (Chondroitin Sulphate=CS, Glucosamin, and Diacerein) in the years 2006-2011.

Methods SIDIAP (www.sidiap.org) contains anonymised medical records and pharmacy invoice data for a representative >5 million people (80% of the total population) from Catalonia (Spain). Participants were patients aged 40 years or older included in SIDIAP with a new diagnosis of OA in the period 2006-2011. We ascertained use of paracetamol and SYSADOA using official pharmacy invoice records in the same period.

We assessed clinical characteristics (including age, gender, body mass index, and common co-morbid conditions) of SYSADOA users and compared them to paracetamol users.

Finally, we calculated incidence rates (and 99%CI) of new users of each of the three subsidized SYSADOA drugs among participants in this same period using Poisson regression.

Results We identified 281,356 patients with an incident clinical diagnosis of OA in 2006-2011. Among these, 91,515(32.5%) and 211,844(75.3%) purchased SYSADOA and paracetamol respectively. Paracetamol users were older (mean 68.4 VS 63.6 years; p<0.001), and more likely to have comorbid conditions such as hypertension (56.8% vs 46.9%), type 2 diabetes (19.2% vs 13.5%), and ischaemic heart disease (4.1% vs 2.1%). Knee OA was more common among users of SYSADOA (52.2%) than in paracetamol users (42.0%).

Incidence of use of Glucosamin and Diacerein decreased from 12.0/100 person-years (99%CI 11.6-12.5) and 4.2/100(4.0-4.5) in 2006 to 5.0/100(4.6-5.4) and 1.4/100(1.2-1.6) in 2011 respectively. By contrast, incidence of CS use increased from 9.3/100(8.9-9.7) to 14.1/100(13.4-14.7) in this same period.

Conclusions Almost 1/3 of the newly diagnosed OA patients start treatment with SYSADOA in Spain. When compared to users of paracetamol, new users of SYSADOA are younger, more likely to suffer knee OA, and have a better cardiovascular risk profile.

Incidence of use of the 3 available oral SYSADOA in Spain has changed in the last few years: while new users of CS increased yearly, numbers of incident glucosamin and diacerein users have decreased.

Disclosure of Interest D. Prieto-Alhambra Grant/research support from: Unrestricted grant from BIOIBERICA SA, M. Herrero Barbero Employee of: BIOIBERICA SA, J. Vergés Employee of: BIOIBERICA SA