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Original Articles

Patient Registries of Acute Coronary Syndrome

Assessing or Biasing the Clinical Real World Data?

Ignacio Ferreira-González, MD, PhD; Josep R. Marsal, BSc; Francesca Mitjavila, MD; Antoni Parada, BSc; Aida Ribera, BSc, PhD; Purificación Cascant, RN; Núria Soriano, MD; Pedro L. Sánchez, MD, PhD; Fernando Arós, MD, PhD; Magda Heras, PhD, MD; Héctor Bueno, PhD, MD; Jaume Marrugat, MD, PhD; José Cuñat, MD, PhD; Emilia Civeira, MD, PhD and Gaietà Permanyer-Miralda, MD, PhD

From the Vall d’Hebron Hospital (I.F.-G., J.R.M., A.R., P.C., N.S., G.P.-M.), Barcelona; CIBER Epidemiología y Salud Pública (CIBERESP) (I.F.-G., J.R.M., F.M., A.R., P.C., N.S., G.P.-M.); Agència d’Avaluació de Tecnologia i Recerca Mèdiques (A.P.), Barcelona; Hospital General Universitario "Gregorio Marañón" (P.L.S., H.B.), Madrid; Hospital Txagorritxu (F.A.), Vitoria; Hospital Clinic (M.H.), Barcelona, IDIBAPS; Institut Municipal d’Investigació Mèdica (IMIM. Hospital del Mar) (J.M.), Barcelona; Hospital La Fe (J.C.), Valencia; and Hospital Clínico (E.C.), Zaragoza, Spain.

Correspondence to Ignacio Ferreira-González. Epidemiology Unit, Cardiology Department, Vall d’Hebron Hospital, Passeig Vall d’Hebron 119-129, 08035, Barcelona, Spain. E-mail nacho_ferreira{at}hotmail.com

Received December 15, 2008; accepted August 7, 2009.

Background— The risk of selection bias in registries and its consequences are relatively unexplored. We sought to assess selection bias in a recent registry about acute coronary syndrome and to explore the way of conducting and reporting patient registries of acute coronary syndrome.

Methods and Results— We analyzed data from patients of a national acute coronary syndrome registry undergoing an audit about the comprehensiveness of the recruitment/inclusion. Patients initially included by hospital investigators (n=3265) were compared to eligible nonincluded (missed) patients (n=1439). We assessed, for 25 exposure variables, the deviation of the in-hospital mortality relative risks calculated in the initial sample from the actual relative risks. Missed patients were of higher risk and received less recommended therapies than the included patients. In-hospital mortality was almost 3 times higher in the missed population (9.34% [95% CI, 7.84 to 10.85] versus 3.9% [95% CI, 2.89 to 4.92]). Initial relative risks diverged from the actual relative risks more than expected by chance (P<0.05) in 21 variables, being higher than 10% in 17 variables. This deviation persisted on a smaller degree on multivariable analysis. Additionally, we reviewed a sample of 129 patient registries focused on acute coronary syndrome published in thirteen journals, collecting information on good registry performance items. Only in 38 (29.4%) and 48 (37.2%) registries was any audit of recruitment/inclusion and data abstraction, respectively, mentioned. Only 4 (3.1%) authors acknowledged potential selection bias because of incomplete recruitment.

Conclusions— Irregular inclusion can introduce substantial systematic bias in registries. This problem has not been explicitly addressed in a substantial number of them.

Key Words: acute coronary syndrome • selection bias

The online-only Data Supplement is available at http://circoutcomes.ahajournals.org/cgi/content/full/CIRCOUTCOMES.108.844399/DC1.

This article has been cited by other articles:

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