Objectives: To measure persistence with antihypertensive drug therapy in patients initiating treatment with mono or combination therapy.
Methods: Data analysis was based on two cohorts of patients, that is, a cohort derived from the registration of drug prescriptions in all residents of the Lombardy region receiving Public Health Service and a cohort of patients followed by general practitioners throughout the Italian territory. Data were limited to patients aged 40-80 years who received their first antihypertensive drug prescription (n = 433,680 and 41,199, respectively) in whom persistency of treatment was examined over 9 months. A proportional hazards model was fitted to estimate the association between the pattern of initial antihypertensive drug therapy and risk of treatment discontinuation. Data were adjusted for available potential confounders.
Results: Taking patients starting with diuretic monotherapy as reference, the adjusted risk of treatment discontinuation was progressively lower in patients starting with monotherapy other than a diuretic, a two-drug combination, including a diuretic and a two-drug combination without a diuretic. No significant difference in the risk of discontinuation was seen between extemporaneous and fixed dose combinations, including a diuretic, that is, the only combination reimbursable by Public Health Service and, thus, available in the database. Data were similar for the two cohorts.
Conclusion: Initiating treatment with a combination of two drugs is associated with a reduced risk of treatment discontinuation.