Predictors of missed research appointments in a randomized placebo-controlled trial.

Abstract

The primary aim of this study was to determine predictors of missed research appointments in a prospective randomized placebo injection-controlled trial with evaluations 1 to 3 and 5 to 8 months after enrollment. This study represents a secondary use of data from 104 patients that were enrolled in a prospective randomized controlled trial of dexamethasone versus lidocaine (placebo) injection for various diagnoses. Patients were enrolled between June 2003 and February 2008. Sixty-three patients (61%) had lateral epicondylosis, 17 patients (16%) had trapeziometacarpal arthrosis, and 24 patients (23%) had de Quervain syndrome. Each patient completed a set of questionnaires at time of enrollment. Bivariable and multivariable analyses were used to determine factors associated with missed research appointments. Fourteen patients (13%) did not return for the first follow-up and 33 patients (32%) did not return for the second follow-up. The best multivariable logistic regression model for missing the first research visit explained 35% of the variability and included younger age, belief that health can be controlled, and no college education. The best model for missing the second research visit explained 17% of the variability and included greater pain intensity, less personal responsibility for health, and diagnosis (trapeziometacarpal arthrosis and de Quervain syndrome). Younger patients with no college education, who believe their health can be controlled, are more likely to miss a research appointment when enrolled in a randomized placebo injection-controlled trial.