Calculation of direct antiretroviral treatment costs and potential cost savings by using generics in the German HIV ClinSurv cohort

Abstract

BACKGROUND/AIM OF THE STUDY: The study aimed to determine the cost impacts of antiretroviral drugs by analysing a long-term follow-up of direct costs for combined antiretroviral therapy, cART, -regimens in the nationwide long-term observational multi-centre German HIV ClinSurv Cohort. The second aim was to develop potential cost saving strategies by modelling different treatment scenarios.

Methods: Antiretroviral regimens (ART) from 10,190 HIV-infected patients from 11 participating ClinSurv study centres have been investigated since 1996. Biannual data cART-initiation, cART-changes, surrogate markers, clinical events and the Centre of Disease Control- (CDC)-stage of HIV disease are reported. Treatment duration was calculated on a daily basis via the documented dates for the beginning and end of each antiretroviral drug treatment. Prices were calculated for each individual regimen based on actual office sales prices of the branded pharmaceuticals distributed by the license holder including German taxes.

Results: During the 13-year follow-up period, 21,387,427 treatment days were covered. Cumulative direct costs for antiretroviral drugs of €812,877,356 were determined according to an average of €42.08 per day (€7.52 to € 217.70). Since cART is widely used in Germany, the costs for an entire regimen increased by 13.5%. Regimens are more expensive in the advanced stages of HIV disease. The potential for cost savings was calculated using non-nucleotide-reverse-transcriptase-inhibitor, NNRTI, more frequently instead of ritonavir-boosted protease inhibitor, PI/r, in first line therapy. This calculation revealed cumulative savings of 10.9% to 19.8% of daily treatment costs (50% and 90% substitution of PI/r, respectively). Substituting certain branded drugs by generic drugs showed potential cost savings of between 1.6% and 31.8%.

Conclusions: Analysis of the data of this nationwide study reflects disease-specific health services research and will give insights into the cost impacts of antiretroviral therapy, and might allow a more rational allocation of resources within the German health care system.

Figure 1. Cumulative use (in days) of antiretroviral classes by year.

(* The decrease of treatment days in 2008 is explained by a reporting delay for some of the most recent cases within the database at the end of the observation period).

Figure 2. Distribution of the amount of different antiretrovirals per regimen in % of all treatment days.

Observation period 1996–2008.

Figure 3. Market share of selected antiretrovirals of the nRTI-class (% of all treatment days per year).

Figure 4. Mean daily treatment costs of antiretrovirals by class and year after adjustment for the German consumer price index (1996 = 100), annual increments of consumer price index in %: 1996: 1.4%, 1997: 1.9%; 1998: 1.0%; 1999: 0.6%; 2000: 1,4%; 2001: 1.9%; 2002: 1.5%; 2003: 1.0%; 2004: 1.7%; 2005: 1.5%; 2006: 1.6%; 2007: 2.3%; 2008: 2.6%.

Figure 5. Direct costs of antiretrovirals per line of regimen (pharmacy prices including taxes in Euros.

Fine-printed numbers represent sample sizes. p<0.0001 for differences between regimen line groups).

Figure 6. Means of daily taken pills (bit) and average costs of each single antiretroviral pill by year.