The economic consequences of non-adherence to lipid-lowering therapy: results from the Anglo-Scandinavian-Cardiac Outcomes Trial.
BACKGROUND
Adherence to lipid-lowering therapy in clinical practice is less than ideal. Analysis of registry data has indicated that this is associated with poor outcomes. The objective of the present analysis was to assess the impact of high adherence to drug (defined as > 80% of days covered), compared with low adherence to drug (< 50% of days covered) in terms of risk of events and long-term economic consequences.


METHODS
Open-label follow up of a randomised placebo-controlled trial in hypertensive patients.


METHODS
Cox proportional hazards and Poisson regression models were used to assess the hazard ratio of patients with high adherence compared with low adherence while controlling for cardiovascular risk. A Markov model was used to predict the long-term costs and health outcomes associated with poor adherence during the follow-up period.


RESULTS
Both statistical models indicated that high adherence is associated with improved prognosis [Cox model: 0.75; 95% confidence interval (CI): 0.56-0.98, Poisson model hazard ratio: 0.73; 95% CI: 0.58-0.98]. Discounted at 3.5% per year, the Markov model predicts that as a consequence of higher adherence during the follow-up period, costs would be higher (1689 pounds per patient compared with 1323 pounds per patient) because of higher drug costs, but the projected survival and quality-adjusted survival (QALY) would also be longer (10.83 compared with 10.81 life years and 8.13 compared with 8.11 QALYs).


CONCLUSIONS
Given the higher risk of cardiovascular events associated with low adherence shown here, measures to improve adherence are an important part of the prevention of cardiovascular disease.
Lindgren
P
P
i3 Innovus, Stockholm, Sweden. Peter.lindgren@i3innovus.com
Eriksson
J
J
Buxton
M
M
Kahan
T
T
Poulter
N R
NR
Dahlöf
B
B
Sever
P S
PS
Wedel
H
H
Jönsson
B
B
D000328:Adult; D000368:Aged; D000924:Anticholesteremic Agents / Q000191:economics / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000191:economics / Q000627:therapeutic use*; D000069059:Atorvastatin; D002318:Cardiovascular Diseases / Q000209:etiology; D003327:Coronary Disease / Q000517:prevention & control; D003362:Cost-Benefit Analysis; D005260:Female; D005500:Follow-Up Studies; D006538:Heptanoic Acids / Q000191:economics / Q000627:therapeutic use*; D006801:Humans; D006949:Hyperlipidemias / Q000188:drug therapy / Q000191:economics; D006973:Hypertension / Q000188:drug therapy* / Q000191:economics; D008297:Male; D008390:Markov Chains; D055118:Medication Adherence; D008875:Middle Aged; D011758:Pyrroles / Q000191:economics / Q000627:therapeutic use*; D019057:Quality-Adjusted Life Years; D012307:Risk Factors
D000924:Anticholesteremic Agents; D000959:Antihypertensive Agents; D006538:Heptanoic Acids; D011758:Pyrroles; D000069059:Atorvastatin