Toogood J H, Andreou P, Baskerville J
Victoria Hospital, London, Ontario, Canada.
J Allergy Clin Immunol. 1996 Sep;98(3):555-62. doi: 10.1016/s0091-6749(96)70089-1.
A "survival" model offers certain ethical and practical advantages over alternative experimental designs if used to compare antiasthmatic inhaled steroid formulations. The model requires an objective daily measure of therapeutic effect (e.g., peak expiratory flow rate, which may be expressed as the lower of two daily measurements (LPF) or as diurnal variability (DVPF). The relative efficiency of these two measures is unknown.
This study was conducted to determine the relative efficiency of LPF and DVPF.
We analyzed data from a placebo-controlled comparison of an active inhaled formulation of budesonide versus an inactive oral formulation. The primary outcome measure in this design is the number of days from the time the test treatments start until a statistically significant deterioration occurs from an optimal asthma control value established at baseline.
DVPF proved less sensitive than LPF; that is, fewer patients relapsed during the 8-week trial period: 32 versus 41, respectively. Also, the median interval until relapse was longer: 24 versus 9 days. With LPF, inhaled budesonide proved more effective than placebo or oral budesonide (p = 0.03), whereas DVPF failed to discriminate among the test treatments (p = 0.38). LPF correlated with all three symptom indices (p > or = 0.003) and two of three spirometric indices measured concomitantly (p < or = 0.04). DVPF did not correlate with any index (p > or = 0.10).
In this experimental model, LPF proved more sensitive and valid than DVPF as an indicator of differences in antiasthmatic potency between two inhaled steroid formulations.
如果用于比较抗哮喘吸入性类固醇制剂，“生存”模型相对于其他实验设计具有某些伦理和实际优势。该模型需要对治疗效果进行客观的每日测量（例如，呼气峰值流速，可表示为每日两次测量中的较低值（LPF）或昼夜变异性（DVPF））。这两种测量方法的相对效率尚不清楚。
本研究旨在确定LPF和DVPF的相对效率。
我们分析了一项布地奈德活性吸入制剂与非活性口服制剂的安慰剂对照比较的数据。该设计的主要结局指标是从试验治疗开始到从基线确定的最佳哮喘控制值出现统计学显著恶化的天数。
DVPF被证明不如LPF敏感；也就是说，在8周试验期内复发的患者较少：分别为32例和41例。此外，复发前的中位间隔时间更长：24天对9天。使用LPF时，吸入布地奈德比安慰剂或口服布地奈德更有效（p = 0.03），而DVPF未能区分试验治疗组（p = 0.38）。LPF与所有三个症状指标相关（p≥0.003），并与同时测量的三个肺功能指标中的两个相关（p≤0.04）。DVPF与任何指标均无相关性（p≥0.10）。
在这个实验模型中，LPF作为两种吸入性类固醇制剂抗哮喘效力差异的指标，比DVPF更敏感、更有效。
