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|Title: ||Withdrawal from treatment as an outcome in the Isolde study of COPD|
|Authors: ||Calverley, PMA|
|Keywords: ||health status|
|Publication Date: ||2003|
|Publisher: ||American College of Chest Physicians|
|Citation: ||Chest. 124 (4) 1350-1356|
|Abstract: ||Objectives: To investigate the determinants of patient withdrawal from our study, and the effect
of these withdrawals on the outcome of treatment with inhaled corticosteroids in patients with
Design: A double-blind, placebo-controlled, randomized trial.
Setting: Eighteen outpatient centers in the United Kingdom.
Participants: Seven hundred fifty-one patients with stable COPD defined clinically as baseline postbronchodilator FEV1 > 0.8 L and < 85% predicted, FEV1/FVC ratio < 70%, and FEV1 change after albuterol < 10% of predicted.
Intervention: Random assignment of either 500 micrograms bid of inhaled fluticasone propionate (FP)using a spacer device or an identical placebo inhaler. Treatment was continued for 3 years or
until patients withdrew from follow-up.
Measurements and results: Postbronchodilator FEV1 was measured on three occasions before
randomization and every 3 months thereafter. Health status was assessed by the disease-specific
St. George Respiratory Questionnaire (SGRQ) and the modified short-form 36 questionnaire
(SF-36) at baseline and every 6 months. Three hundred thirty-nine patients withdrew, of whom
156 patients received FP. Prescription of frequent courses of oral prednisolone was the most
common reason for withdrawing as specified in the protocol (69 patients in the FP group
withdrew due to respiratory symptoms, compared with 93 patients in the placebo group). This
explained the significantly greater dropout of placebo-treated patients that was most evident
when FEV1 was < 50% predicted. Patients withdrawing had a significantly more rapid decline in health status, measured by both the SGRQ and the SF-36 (p < 0.001). Those withdrawing from the placebo group had a more rapid decline in FEV1 and more exacerbations than the FP-treated
groups. Baseline FEV1 was lower in dropouts than in patients completing the study receiving
placebo, but there was no difference between the respective groups receiving FP.
Conclusions: Patients who withdrew from follow-up were those with the most rapidly deteriorating
health status and lung function. Losing these patients from the final analysis can reduce the
power of a study to achieve its primary end point.|
|Appears in Collections:||School of Health Sciences and Social Care Research Papers|
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