Download the full report (112 p.) - KCE

KCE Reports 111 Interventions in Alzheimer’s Disease 69
6.3.4 Switching of ChEIs
Overall and also when limited to patients who started ChEI treatment in 2003 or before
the proportion of patients who switched during the observation period was not higher
than 5%. This switch rate of about 5% between ChEI is very similar to the 6% rate
reported by Herrmann et al. 129
6.3.5 Time to discontinuation of ChEI treatment
6.3.5.1 Overall analysis
In our dataset (2502 patients), the median time between two prescriptions was 30 days,
and was used as an estimate for the treatment duration (thus added to the last date of
the prescription). The median time to treatment discontinuation is 1006 days (95% CI:
905 to 1106), as shown below (using a maximum gap of 200 days between
prescriptions, and censoring discontinuation for death or for completed follow up). A
total of 294 patients (11.8%) had only one prescription of ChEl during the 2002-2006
study period. In the Ontario study the median time to discontinuation of ChEIs
(censored for death or completed follow-up) was 651 days, 129 allowing a grace period of
120 days after the presumed end date of the initial prescription and including a
treatment period of 120 days systematically added to the last prescription date. Figure 4
suggests there is no significant impact on drug discontinuation of the patient reevaluation
after the first 6 months of ChEI treatment, which is required for obtaining
continued drug reimbursement. When the analysis is not censored for death then the
median time to treatment discontinuation is reduced to 594 days (95% CI: 551 to 694).
Figure 4: Time to discontinuation of ChEl treatment (censored for death and
end of follow-up)