To investigate whether cardiovascular outcome incidence was different in patients either requiring or not requiring add-on treatment is really successful.
The analyses concern 9711 hypertensives included in the intention-to-treat population of FEVER. The patients were grouped as patients not requiring (no-add-on) or requiring (add-on) additional therapy on top of randomized treatment throughout the follow-up. Within each of the two groups, analyses were also done separately for patients randomized to felodipine or placebo. Sensitivity analyses have been carried out by using a marginal structural model method with onset of add-on treatment used as a time varying covariate and SBP/DBP as time dependent confounders.
Information on possible add-on treatment was available for 9681 (99.7%) patients, 5994 (61.9%) without add-on therapy and 3687 (38.1%) with add-on therapy. In add-on patients averageon-treatment SBP and DBP remained higher (4.3 and 1.7 mmHg respectively) than in no-add-on patients, despite similar values of baseline BP. In both groups patients randomized to felodipine achieved lower SBP/DBP values (no-add-on −3.4/−1.8 mmHg; add-on −4.6/−2.5 mmHg) than patients randomized to placebo. All outcomes had a much lower incidence in no-add-on patients, with RRs ranging from 0.25 to 0.436, and being particularly low for fatal outcomes (both cardiovascular and non-cardiovascular). No-add-on patients were at a low to moderate risk, whereas add-on patients were at very high risk. The incidence of all strokes was much lower in those with no-add-one treatment (HR0.341 95%CI: 0.281–0.414, P < 0.001) and the similar results was also find in all cardiovascular events (HR:0.378, 95% CI: 0.268–0.531, P < 0.001).
Our finding calls attention to the possibility that additional therapy may not always be accompanied by the expected reduction in outcomes.
© 2012 Lippincott Williams & Wilkins, Inc.