International Journal of Technology Assessment in Health Care



GENERAL ESSAYS

DOES CLINICAL TRIAL SUBJECT SELECTION RESTRICT THE ABILITY TO GENERALIZE USE AND COST OF HEALTH SERVICES TO “REAL LIFE” SUBJECTS?


Wendy A. Kennedy a1, Claudine Laurier a1, Jean-Luc Malo a2, Heberto Ghezzo a3, Jocelyne L'archevêque a2 and André-Pierre Contandriopoulos a1
a1 University of Montreal
a2 Hôpital du Sacré Coeur de Montréal
a3 Meakins Christie Laboratories

Abstract

Objectives: To explore one aspect of the external validity of the randomized controlled trial (RCT), specifically how being selected for inclusion in a trial and having participated has influenced the use and cost of asthma-related health services.

Methods: Services used by asthmatic users of inhaled corticosteroids (iCSTs) having previously participated in an RCT (TS, n = 46) were compared with individuals who had never participated (NS, n = 51).

Results: TS were more likely to use higher ([greater-than-or-equal]400 μg) daily doses of iCSTs than NS (OR, 3.3; 95% CI, 1.1–8.3) but less likely to visit emergency departments (OR, 0.3; 95% CI, 0.1–0.7). Total asthma-related costs did not differ significantly.

Conclusions: Subject differences may impede generalizing from RCTs to real life.


Key Words: Clinical trial; Economic evaluation; Asthma; Cost-effectiveness.