Chest
Volume 131, Issue 1, January 2007, Pages 20-28
Journal home page for Chest

Original Research
Risk Indexes for Exacerbations and Hospitalizations Due to COPD

https://doi.org/10.1378/chest.06-1316Get rights and content

Abstract

Objective:The ability to predict exacerbations in patients with COPD might permit more rational use of preventive interventions. Our objective was to develop risk indexes for exacerbations and hospitalizations due to exacerbations that might be applied to the individual patient.

Methods:Spirometry, demographics, and medical history were obtained at baseline in 1,829 patients with moderate-to-very severe COPD who entered a trial of inhaled tiotropium. Information about exacerbations and hospitalizations due to exacerbation was collected during the 6-month follow-up period. Analyses of first outcomes were modeled using univariable and multivariable Cox proportional hazards regressions.

Results:During follow-up, 551 patients had at least one exacerbation and 151 patients had at least one hospitalization due to exacerbation. In the multivariable model for exacerbation, older age, percentage of predicted FEV1, duration of COPD, a productive cough, antibiotic or systemic corticosteroid use for COPD in the prior year, hospitalization for COPD in the prior year, and theophylline use at baseline predicted a higher risk. In the multivariable model for hospitalization, older age, percentage of predicted FEV1, unscheduled clinic/emergency department visits for COPD in the prior year, any cardiovascular comorbidity, and prednisone use at baseline were associated with greater risk. Both the exacerbation and the hospitalization models provided moderately good discrimination, the validated concordance indexes being 0.66 and 0.73, respectively. Methods for calculating risk in individual patients are provided.

Conclusions:Spirometry along with a few questions directed to the patient are strongly predictive of exacerbations and related hospitalizations over the ensuing 6 months.

Section snippets

Materials and Methods

The trial was performed in accordance with the recommendations in the Helsinki Declaration of 1975.24The institutional review board of all participating medical centers approved this study. All subjects gave written informed consent.

Details of the study protocol were previously described.23Briefly, all men and women receiving medical care at participating Veterans Affairs medical centers were potential study subjects. Major inclusion criteria were a clinical diagnosis of COPD, age ≥ 40 years,

Results

We randomized 1,829 subjects from among 2,498 candidates who were screened at 26 Veterans Affairs medical centers, of whom 915 were allocated to placebo and 914 to tiotropium. Study subjects were predominately white (91%) and male (99%), reflecting the composition of patients who receive medical care in Veterans Affairs medical facilities. As shown inTable 1, the average subject was elderly (mean age, 68 ± 9 years), had relatively severe COPD (FEV1, 36% predicted), received multiple respiratory

Discussion

Using a database from a large trial, we identified advancing age and low levels of lung function as major independent risk factors for both exacerbations and hospitalizations due to exacerbations. Other important independent risk factors in both models are medical events (frequencies of antibiotic and systemic corticosteroid use, unscheduled clinic/ED visits, and hospitalization, all for COPD in the prior year) that as a group might be viewed as reflecting an intrinsic susceptibility to

Participating Investigators and Study Staff

Other investigators and study staff at individual Veterans Affairs medical centers are as follows: Bay Pines: Dr. C. Cote, K. Wilson; Birmingham: Dr. A. Cooper, Jr., J. Bowden, R. Culbreth, J. Cooper; Boston: Dr. D. Gottlieb, K. Hickson; Bronx: Dr. M. Lesser, Dr. G. Schilero; Buffalo: Dr. S. Sethi, K. Eschberger; Dallas: Dr. M. Hasan, C. Lusk; Durham: Dr. S. Young, J. Smith; Gainesville: Dr. R. Gonzalez-Rothi, L. Thompson; Hampton: Dr. B. Rossheim, G. Troupe; Hines: Dr. N. Gross, A. Burns;

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    The Duke Clinical Research Institute managed data for the trial.

    Administrative support for all study centers was provided by the Minnesota Veterans Research Institute.

    Financial support was provided by Boehringer Ingelheim and Pfizer.

    Dr. Niewoehner has received grants, honoraria, or advisory fees from Boehringer-Ingelheim, Pfizer, AstraZeneca, GlaxoSmithKline, Adams Respiratory Therapeutics, and Sanofi Pasteur within the past 3 years. Dr. Rice has received honoraria from Boehringer-Ingelheim and Pfizer within the past 3 years. Dr. Sharafkhaneh has received honoraria from Boehringer-Ingelheim, Pfizer, and GlaxoSmith-Kline. Dr. Krumpe has received grants, honoraria, or advisory fees from Altana, Astra-Zeneca, Boehringer-Ingelheim, Chiron, and Pulmonix. Dr. Kesten is an employee of Boehringer-Ingelheim. Dr. Lokhnygina, Dr. Kuschner, Dr. Sarosi, and Ms. Pieper report no potential conflicts of interest.

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