Table 3.

Estimation of Rates of Adverse Events 24 Months Before and 12 Months After Generic Valsartan Commercialization

All UsersGenericsBrand NameDifference in Proportions95% CI
Trend before generics commercialization (%, 1st to 23rd month)0.2NA0.2NANA
Level change the month of generics commercialization (%, 24th month)−1.611.7*−5.417.19.9 to 24.3
One-year trend change after generics commercialization (%, 24th to 36th month)0.0−0.5−0.50.0−1.0 to 1.1
  • For interrupted time series analyzed by negative binomial segmented regression (%=ecoefficient-1×100). All users include generic and brand-name users; generics include 5 different versions of generic valsartan. 95% CI indicates 95% confidence interval around the difference in proportions; NA, not applicable; difference in proportions of change in adverse events between generic and brand-name users.

  • * P<0.001.

  • P<0.05.

  • P<0.0001.