Clinical usefulness of n-of-1 randomized controlled trials in patients with nonreversible chronic airflow limitation.
To determine if n-of-1 randomized controlled trials (n-of-1 RCT) are useful in the care of patients with nonreversible chronic airflow limitation (CAL). Individual trials had a double-blind, randomized, multiple crossover design. Patients with CAL were recruited from several respirology practices. For each individual trial the main outcome measure was a symptom questionnaire; peak flow measurements were used as a secondary measure. Physicians' plans of management (before and after trials) and confidence in the plans were determined. The proportion of trials that provided a definite clinical or statistical answer was established. Patients were followed, and long-term adherence to decisions based on n-of-1 RCT was examined. A total of 26 n-of-1 RCT in patients with CAL were attempted; 18 of these (69%) were completed. After 17 (94%) of the completed trials clinicians expressed a high degree of confidence in their management plans, confidence that was not, in any case, present before the trial. After 8 n-of-1 RCT (44% of all completed, or 31% of all trials) clinicians decided to stop the drug, which would otherwise have been continued indefinitely. In all 17 of the clinically definite n-of-1 RCT, the management decision that followed the trial was still being adhered to 40 months (on average) after completion of the trial. The results support the feasibility and usefulness of n-of-1 RCT in respirology practice.
Department of Medicine, St. Joseph's Hospital, Hamilton, Ontario, Canada.
A
A
Patel
R
R
Jaeschke
G H
GH
Guyatt
J L
JL
Keller
M T
MT
Newhouse
D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy* / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires