Public Health Outcomes May Differ After Switching from Brand-Name to Generic Angiotensin II Receptor Blockers.

BACKGROUND

It is unclear whether generics are as safe as brand-name drugs in cardiology. For public health surveillance purposes, we evaluated if switching from the brand-name losartan, valsartan, or candesartan impacted the occurrence of the following outcomes: emergency room (ER) consultations, hospitalizations, or death.

STUDY

DESIGN

This was a retrospective cohort study.

METHODS

This study was conducted in the Quebec Integrated Chronic Disease Surveillance System, including healthcare administrative data of the population of Quebec, Canada. We included brand-name users of losartan, valsartan, or candesartan aged ≥ 66 years who had undergone ≥ 30 days of stable treatment on the brand-name drug prior to cohort entry (substitution time-distribution matching was used to prevent immortal time bias). Outcomes up to 1 year were compared between groups using multivariable Cox proportional hazards regression models (validity assumptions were verified).

RESULTS

In our cohorts (losartan, n =15,783; valsartan, n =16,907; candesartan, n =26,178), mean age was 76-78 years, 59-66% were female, 90-92% had hypertension, and 13-15% had heart failure. Validity assumptions were violated for losartan only. For patients switched to generic valsartan, the hazard ratio (95% confidence interval) was 1.07 (0.99-1.14) for ER consultation, 1.26 (1.14-1.39) for hospitalization, and 1.01 (0.61-1.67) for death. The corresponding rates for candesartan were 1.00 (0.95-1.05), 0.96 (0.89-1.03), and 0.57 (0.37-0.88), respectively.

CONCLUSIONS

We observed an increased risk of hospitalizations for patients switched to generic valsartan, and a decreased risk of death for patients switched to generic candesartan, compared with those who continued taking the brand-name drug. The differences between generic and brand-name drugs may lead to some differences in public health outcomes, but this safety signal must be further studied using other cohorts and settings.