A cohort study of effectiveness of acetylcholinesterase inhibitors in Alzheimer's disease

To characterise the population of Alzheimer's disease patients treated with acetylcholinesterase inhibitors, to analyse effectiveness and drug safety in the clinical practice, and to identify variables that may predict the response to therapy. From September 2000 to December 2001, a total of 5,462 patients diagnosed with mild to moderate Alzheimer's disease were enrolled at the time of their first prescription of the study drugs and followed up for an average of 10.5 months. Responders were defined as patients with a mini-mental state examination (MMSE) score improvement of 2 or more points from baseline after 9 months of therapy. At 9 months, 2,853 patients (52.2%) completed the study. The mean change from baseline in MMSE scores was an improvement of 0.5 points (+/-3.0). The proportion of responders to the therapy was 15.7% at 9 months. A greater probability of response at 9 months was observed among patients without concomitant diseases at baseline [odds ratio (OR)=2.1, 95% confidence interval (CI) 1.5-2.9] and among those with a response at 3 months (OR=20.6, 95% CI 17.2-24.6). During the study period, 285 patients (5.2%) discontinued the treatment because of an adverse drug reaction. Effectiveness of acetylcholinesterase inhibitors on cognitive symptoms of patients with mild to moderate Alzheimer's disease is modest. At 9 months, improvement was evident only in a subgroup of patients without concomitant diseases and who had demonstrated a response at 3 months.