Prevalence, incidence and persistence of etanercept and adalimumab in Norway 2005-2009

Abstract

Purpose: Examining the prevalence, incidence and persistence of use of etanercept and adalimumab in Norway during 2005-2009.

Methods: We retrieved data from the nationwide Norwegian Prescription Database (NorPD) for all individuals who were dispensed etanercept or adalimumab from pharmacies during 2005-2009. The NorPD covers the total Norwegian population in ambulatory care. Key measurements were one-year prevalence, incidence rate and persistence (minimum refill).

Results: The one-year prevalence for etanercept and adalimumab was 1.59‰ (n = 3840) for men and 1.85‰ (n = 4483) for women in 2009, an increase from 0.76‰ (n = 1752) for men and 1.21‰ (n = 2830) for women from 2005. The prevalence increased during the entire study time in all ages, with the highest prevalence for both genders among those aged 50-69. A total of 7786 individuals started therapy with etanercept or adalimumab during 2005-2009. Annual incidence of new users increased with 23.6% from 2005 to 2009. Sixty one percent of new users redeemed etanercept as the first drug, and 39% redeemed adalimumab. Sixty seven percent of all individuals who received etanercept or adalimumab in 2005 refilled their prescription at least once each of the following 4 years.

Conclusions: Both prevalence and incidence of use of etanercept and adalimumab increased in Norway during 2005-2009. A high proportion of the individuals redeemed prescriptions regularly over 5 years.