Grimm W, Müller H H
Department of Medicine and Medical Center for Methodology and Health Research, Institute of Medical Biometry and Epidemiology, Philipps-University of Marburg, Germany.
Am J Med. 1999 Feb;106(2):138-43. doi: 10.1016/s0002-9343(98)00406-9.
Fluid extracts of Echinacea purpurea are widely used for the prevention and treatment of colds and respiratory infections, although the clinical efficacy of this agent has not been proven.
A total of 109 patients with a history of more than 3 colds or respiratory infections in the preceding year were randomly assigned to receive 4 mL fluid extract of Echinacea purpurea or 4 mL placebo-juice twice a day in a double-blind manner. (One patient withdrew his consent before taking the first dose of the allocated medication; thus, only 108 patients were included for analysis.) The incidence and severity of colds and respiratory infections were determined during 8 weeks of follow-up, based on patient reported symptoms together with findings on physical exam. The severity of each infection was graded by the investigators. Relative risks (RR) and 95% confidence intervals (CI) were estimated.
During the 8-week treatment period, 35 (65%) of 54 patients in the Echinacea group and 40 (74%) of 54 patients in the placebo group had at least one cold or respiratory infection [RR = 0.88; 95% CI (0.60, 1.22)]. The average number of colds and respiratory infections per patient was 0.78 in the Echinacea group, and 0.93 in the placebo group [difference = 0.15; 95% CI (-0.12, 0.41), P = 0.33]. Median duration of colds and respiratory infections was 4.5 days in the Echinacea group and 6.5 days in the placebo group (95% CI: -1, +3 days; P = 0.45). There were no significant differences between treatment groups in the number of infections in each category of severity. Side effects were observed in 11 patients (20%) of the Echinacea group and in seven patients (13%) of the placebo group (P = 0.44).
Treatment with fluid extract of Echinacea purpurea did not significantly decrease the incidence, duration or severity of colds and respiratory infections compared to placebo.
紫锥菊的流浸膏被广泛用于预防和治疗感冒及呼吸道感染，尽管该药物的临床疗效尚未得到证实。
共有109例在前一年患感冒或呼吸道感染超过3次的患者被随机分配，以双盲方式接受每日两次、每次4 mL紫锥菊流浸膏或4 mL安慰剂果汁。（一名患者在服用分配的药物首剂前撤回同意书；因此，仅108例患者纳入分析。）根据患者报告的症状及体格检查结果，在8周的随访期间确定感冒和呼吸道感染的发生率及严重程度。每位研究者对每种感染的严重程度进行分级。估计相对风险（RR）和95%置信区间（CI）。
在8周的治疗期内，紫锥菊组54例患者中有35例（65%）、安慰剂组54例患者中有40例（74%）至少发生一次感冒或呼吸道感染[RR = 0.88；95% CI（0.60，1.22）]。紫锥菊组每位患者感冒和呼吸道感染的平均次数为0.78次，安慰剂组为0.93次[差值 = 0.15；95% CI（-0.12，0.41），P = 0.33]。紫锥菊组感冒和呼吸道感染的中位持续时间为4.5天，安慰剂组为6.5天（95% CI：-1，+3天；P = 0.45）。各严重程度类别中的感染次数在治疗组之间无显著差异。紫锥菊组11例患者（20%）和安慰剂组7例患者（13%）观察到副作用（P = 0.44）。结论：与安慰剂相比，紫锥菊流浸膏治疗并未显著降低感冒和呼吸道感染的发生率、持续时间或严重程度。
