A retrospective, population-based analysis of persistence with antihypertensive drug therapy in primary care practice in Italy.
BACKGROUND
Many hypertensive patients discontinue drug therapy despite the increased cardiovascular risk associated with inadequately controlled hypertension. However, most experiments do not address this premature discontinuation of therapy, making it difficult to project the appropriateness of antihypertensive drugs in real-world use.


OBJECTIVE
The goal of this study was to assess patients' persistence with antihypertensive drug therapy in a nonexperimental setting.


METHODS
An administrative database kept by the Local Health Unit of Ravenna, Ravenna, Italy, listing patient baseline characteristics, drug prescriptions, and hospital admissions was used to perform a population-based, retrospective study. The study included all patients who met the following criteria from January I through December 31, 1997: new user of antihypertensive drugs; > or = 20 years of age; receiving a first prescription for a diuretic, beta-blocker, calcium channel blocker, angiotensin II-receptor antagonist (AIIA), or angiotensin-converting enzyme inhibitor. All prescriptions for antihypertensive drugs filled during the 12-month follow-up period were used to define patients as continuers, switchers, or discontinuers on the basis of their persistence with therapy.


RESULTS
A total of 16,783 patients were included in the study analyses: 7,409 men (44.1%) and 9,374 women (55.9%), with an average age of 56.1 +/- 18.3 years (range, 20-105 years). Of this study population, 64.9% (n = 10,894) discontinued treatment over the course of follow-up, 26.9% (n = 4508) continued treatment with the initially prescribed medication (with 5.1% [n = 862] adding another medication for combination therapy), and 8.2% (n = 1381) switched medications. Patients initially prescribed AIIAs were more likely to continue treatment than those initiated on other types of antihypertensives (P < 0.001). Discontinuation was associated with younger age, lower prevalence of concurrent chronic pharmacotherapies, and lower prevalence of previous hospitalizations for cardiovascular disease (all P < 0.001).


CONCLUSIONS
Health care claims data are a powerful tool for measuring continuation of therapy, providing detailed, populationwide epidemiologic and economic information for analyzing antihypertensive drug treatment. Further studies are required to relate pharmacotherapy to outcomes.
Degli Esposti
Luca
L
Health, Economics, and Outcomes Research, CliCon Srl, Ravenna, Italy. luca.degliesposti@clicon.it
Degli Esposti
Ezio
E
Valpiani
Giorgia
G
Di Martino
Mirko
M
Saragoni
Stefania
S
Buda
Stefano
S
Baio
Gianluca
G
Capone
Alessandro
A
Sturani
Alessandra
A
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017891:Pharmacoepidemiology; D011159:Population Surveillance; D012042:Registries; D012189:Retrospective Studies; D017678:Sex Distribution
D000959:Antihypertensive Agents