St. George's Respiratory Questionnaire: MCID

Currently available inhaled bronchodilators used as therapy for chronic obstructive pulmonary disease (COPD) necessitate multiple daily dosing. The present study evaluates the long-term safety and efficacy of tiotropium, a new once-daily anticholinergic in COPD. Patients with stable COPD (age 65.2+/-8.7 yrs (mean+/-SD), n=921) were enrolled in two identical randomized double-blind placebo-controlled 1-yr studies. Patients inhaled tiotropium 18 microg or placebo (mean screening forced expiratory volume in one second (FEV1) 1.01 versus 0.99 L, 39.1 and 38.1% of the predicted value) once daily as a dry powder. The primary spirometric outcome was trough FEV1 (i.e. FEV1 prior to dosing). Changes in dyspnoea were measured using the Transition Dyspnea Index, and health status with the disease-specific St. George's Respiratory Questionnaire and the generic Short Form 36. Medication use and adverse events were recorded. Tiotropium provided significantly superior bronchodilation relative to placebo for trough FEV1 response (approximately 12% over baseline) (p<0.01) and mean response during the 3 h following dosing (approximately 22% over baseline) (p<0.001) over the 12-month period. Tiotropium recipients showed less dyspnoea (p<0.001), superior health status scores, and fewer COPD exacerbations and hospitalizations (p<0.05). Adverse events were comparable with placebo, except for dry mouth incidence (tiotropium 16.0% versus placebo 2.7%, p<0.05). Tiotropium is an effective, once-daily bronchodilator that reduces dyspnoea and chronic obstructive pulmonary disease exacerbation frequency and improves health status. This suggests that tiotropium will make an important contribution to chronic obstructive pulmonary disease therapy.

Health status (or Health-Related Quality of Life) measurement is an established method for assessing the overall efficacy of treatments for asthma and chronic obstructive pulmonary disease (COPD). Such measurements can indicate the potential clinical significance of a treatment's effect. This paper is concerned with methods of estimating the threshold of clinical significance for three widely used health status questionnaires for asthma and COPD: the Asthma Quality of Life Questionnaire, Chronic Respiratory Questionnaire and St George's Respiratory Questionnaire. It discusses the methodology used to obtain such estimates and shows that the estimates appear to be fairly reliable; ie. for a given questionnaire, similar estimates may be obtained in different studies. These empirically derived thresholds are all mean estimates with confidence intervals around them. The presence of these confidence intervals affects the way in which the thresholds may be used to draw inferences concerning the clinical relevance of clinical trial results. A new system of judging the magnitude of clinically significant results is proposed. Finally, an attempt is made to translate these thresholds into scenarios that illustrate what a clinically significant change with treatment may mean to an individual patient.

Lung function in chronic obstructive pulmonary disease (COPD) can be improved acutely by oral corticosteroids and bronchodilators. Whether clinical improvement can be maintained by subsequent inhaled therapy is unknown. COPD patients (n=1,022, mean prebronchodilator forced expiratory volume in one second (FEV1) 36% predicted) initially received formoterol (9 microg b.i.d.) and oral prednisolone (30 mg o.d.) for 2 weeks. After this time, patients were randomised to b.i.d. inhaled budesonide/formoterol 320/9 microg, budesonide 400 microg, formoterol 9 microg or placebo for 12 months. Postmedication FEV1 improved by 0.21 L and health-related quality of life using the St George's Respiratory Questionnaire (SGRQ) by 4.5 units after run-in. Fewer patients receiving budesonide/formoterol withdrew from the study than those receiving budesonide, formoterol or placebo. Budesonide/formoterol patients had a prolonged time to first exacerbation (254 versus 96 days) and maintained higher FEV1 (99% versus 87% of baseline), both primary variables versus placebo. They had fewer exacerbations (1.38 versus 1.80 exacerbations per patient per year), had higher prebronchodilator peak expiratory flow, and showed clinically relevant improvements in SGRQ versus placebo (-7.5 units). Budesonide/formoterol was more effective than either monocomponent in both primary variables. Budesonide/formoterol in a single inhaler (Symbicort) maintains the benefit of treatment optimisation, stabilising lung function and delaying exacerbations more effectively than either component drug alone or placebo.