This finding supports the presence of an overall bias toward false conclusions of efficacy when stopping theophylline openly in patients with CAL who have been taking it for some time, and it provides justification to use n of 1 trials in this setting. However, this conclusion must be qualified because it is based on a post hoc analysis for which confirmation is needed.
Our study neither strengthens nor diminishes the case for considering a trial of theophylline in some patients with irreversible CAL. In particular, our overall negative result does not mean that theophylline should be abandoned because it is ineffective in all such patients. This is because 7 of 34 patients (21%) undergoing n of 1 trials demonstrated a potentially useful response to the drug on the basis of their daily dyspnea scores (Table 4). In each case, the improvement in dyspnea score on theophylline exceeded zero, and the 90% CLs on the estimates made it unlikely, though not impossible, that chance explained the difference. Therefore, given the objectivity of n of 1 trials, the improvement in dyspnea during theophylline therapy in these patients seems genuine. Furthermore, these results corroborate those of previous parallel-group, placebo-controlled trials in which theophylline improved the quality of life and/or exercise capacity. Thus, there remains a rationale for a trial of theophylline in selected patients with irreversible CAL who remain symptomatic despite inhaled bronchodilators.
In conclusion, guiding theophylline therapy for patients with irreversible CAL by n of 1 trials did not improve their quality of life or exercise capacity, or reduce overall drug usage through 1 year compared to standard practice Here birth control online. Although some patients with CAL who underwent n of 1 trials of theophylline noted an improvement in dyspnea, we did not show that routine use of n of 1 trials to establish the value of theophylline in this setting yielded important advantages compared to the standard practice of open, before-after trials. In a post hoc analysis requiring confirmation, using n of 1 trials in patients with CAL who were already taking theophylline reduced drug usage over 6 months compared to standard practice without changes in their quality of life or exercise capacity. Further randomized studies of n of 1 trials vs standard practice for this and other problems are needed before widespread adoption of n of 1 trials can be recommended.