Theophylline for Irreversible Chronic Airflow Limitation: Assignment and Masking

Assignment and Masking
Patients were individually randomized at each site to either n of 1 trials or standard practice. Computer-generated sequences were provided to the sites in sequentially numbered, opaque, sealed envelopes. Opening the envelope constituted randomization and was done by the study physicians immediately before patients began the n of 1 or standard practice trials. Personnel measuring the CRQ and 6-min walk were unaware of the treatment group allocation, and patients were instructed to maintain this blinding.
Participant Flow and Follow-up

Seven patients placed openly on theophylline were not randomized because of side effects (five patients) or a perceived improvement in dyspnea (two patients) such that they did not want to stop taking theophylline (Fig 3). Sixty-eight patients were randomized to n of 1 trials or standard practice (34 patients each) review buy zyrtec online. The baseline characteristics of the groups appeared to be well matched (Table 1). Seven randomized patients (three n of 1 trial patients and four standard practice patients) were withdrawn: five patients died (two from end-stage respiratory failure and one each of complications following pulmonary volume-reduction surgery, recurrent small-cell carcinoma of the lung, and lymphoma); one patient required coronary artery angioplasty for unstable angina; and one patient was lost to follow-up after 1 month. Three other patients experienced major events that likely affected their quality of life and exercise capacity, but they completed the study (one patient in each group underwent elective total hip replacement, and one standard practice patient received chemotherapy for newly diagnosed lymphoma). Analyses excluding the 10 patients having major events did not yield different results from intent-to-treat analyses.

Figure 3. Participant flow and follow-up.Figure 3. Participant flow and follow-up.

Table 1—Baseline Characteristics

Standard Practice Patients n of 1 Trial Patients
No. of subjects 34 34
Age, yr 69 (6.5) 69 (7.6)
No. of women 10 13
No. of ex- or current smokers 34 32
CRQ scoref
Emotional Function 52.9 (10.3) 51.2 (10.7)
Physical Function 34.6 (8.7) 36.2 (8.5)
6-min walk, m 305 (113) 311 (96)
fevl, l 0.92 (0.41) 0.81 (0.29)
% Predicted 33 30
fev/fvc, % 39(11) 38(11)
% Predicted 52 49
Rise in FEVl post-salbutamol, mL 74 (82) 72 (89)
Cointerventions, no. of subjects
Inhaled steroids 21 24
Prednisone 6 4
Home oxygen 12 12
Theophylline level, μM 59 (19) 57 (20)

Category: Airflow Limitation

Tags: irreversible chronic airflow limitations, n of 1 trials, randomized trial, theophylline