[International diffusion of clinical trials carried out in Spain. An analysis based on their publication in scientific journals]

BACKGROUND

Few studies have evaluated the clinical trials carried out in Spain and published in international journals. The present study has analyzed this situation over the period from 1981 to 1990.

METHODS

Spanish studies including "clinical trial" as a key word present in Excerpta Medica CD (Drugs and Pharmacology) or MEDLINE in the CD-ROM version were evaluated.

RESULTS

Two hundred forty-one original articles were obtained. The number of clinical trials was relatively stable from 1981 to 1986 (n = 8.15) increasing to a maximum from 1986 to 1988 (n = 64) with a posterior decrease. The languages of publication were English (51%) and Spanish (49%). A significant increase was observed in the number of articles published in English (p < 0.01) in the last five years. Phase III and IV clinical trials were the most frequent (89%) followed by those of phase II (9%) and phase I (2%). The open design predominated in the phase III-IV trials (58%) over the double blind trials (37%) and the single blind trials (5%). Among the former 70% were comparative and 57% followed randomized treatments. The clinical trials were published in 112 journals, Medicina Clínica (n = 32) and Current Therapeutic Research Clinical and Experimental (n = 6) were the most frequently used in Spanish and English, respectively. Two hundred sixty-three drugs were studied in the clinical trials, cisplatin was the most frequently studied (n = 10). The most commonly studied pharmacologic groups were antiinfectious (n = 40) and cytostatic (n = 35). The number of randomized clinical trials increased significantly after 1986 (p < 0.01).

CONCLUSIONS

An increase in the number of clinical trials published in international journals was observed with preference for publication in English. The growing presence of randomized double blind clinical trials suggests an improvement in the quality of the clinical trials performed in Spain, particularly after 1986.

Placebo-controlled trial of nimodipine in the treatment of acute ischemic cerebral infarction

Nimodipine is a 1,4-dihydropyridine derivative that shows a preferential cerebrovascular activity in experimental animals. Clinical data suggest that nimodipine has a beneficial effect on the neurologic outcome of patients suffering an acute ischemic stroke. Our double-blind placebo-controlled multicenter trial was designed to assess the effects of oral nimodipine on the mortality rate and neurologic outcome of patients with an acute ischemic stroke. One hundred sixty-four patients were randomly allocated to receive either nimodipine tablets (30 mg q.i.d.) or identical placebo tablets for 28 days. Treatment was always started less than or equal to 48 hours after the acute event. The Mathew Scale, slightly modified by Gelmers et al, was used for neurologic assessment. Mortality rate and neurologic outcome after 28 days were used as evaluation criteria. We considered 123 patients to be valid for the analysis of efficacy. Mortality rates did not differ significantly between groups. Neurologic outcome after 28 days of therapy did not differ between groups. However, when only those patients most likely to benefit from any intervention (Mathew Scale sum score of less than or equal to 65 at baseline) were analyzed separately in post hoc-defined subgroups, the nimodipine-treated subgroups showed a significantly better neurologic outcome. This result suggests that some patients with acute ischemic stroke will benefit from treatment with nimodipine tablets.

Weight of financial reward in the decision by medical students and experienced healthy volunteers to participate in clinical trials

The aim of this survey was twofold: to assess the willingness of medical students to volunteer for clinical trials and to evaluate the weight of the financial reward and other general details as seen by healthy volunteers who had already participated in clinical trials. A specific questionnaire was given to each group to be answered anonymously. Among the medical students only 2.9% had already volunteered, 39.7% said that they would never participate, 24.7% would do it for scientific interest, 32.2% for scientific interest and financial reward, and 4.2% for the financial reward alone. In experienced volunteers, financial reward was the main reason to participate (90%) followed by curiosity (6.3%). The financial reward actually received was considered adequate compensation for the time and discomfort by most of the volunteers (83.7%). The information supplied by the research team and the arrangements made to treat any hazardous event were considered adequate (47.5%) or optimal (42.5%). Almost all the experienced volunteers (93.8%) answered positively when asked about participation in future studies. The results show that financial reward is a very important reason for healthy volunteers to participate in clinical trials.

Acceptability of visual analogue scales in the clinical setting: a comparison with verbal rating scales in postoperative pain

Pain is the clinical symptom most difficult to evaluate. Although clinical trials methodology have permitted assessment of pain objectively through rating scales, these strategies have not been used in clinical setting. The present study was undertaken to determine if visual analogue scales could be useful in the measurement of postoperative pain in usual medical practice. The study comprised 212 patients with abdominal, orthopedic or gynecological surgical procedures within the previous 24 h. Patients evaluated their pain using a verbal rating scale (VRS) of five points or a visual analogue scale (VAS) of 10 cm. The investigators also evaluated patient pain through a VAS. The results obtained showed that a high correlation between VRS and VAS could be established in all patients (p less than 0.001). The VAS of patients and researchers were also found to be highly correlated (p less than 0.001). When values of each group were compared by pain intensity a total agreement of VAS scores at low pain level could be established, but differences were found at high pain intensity levels, suggesting that physicians scored lower than patients when pain was severe to unbearable. It is concluded that VAS could be a reliable method to assess pain in clinical setting.

Effects of nisoldipine on renal function in normal volunteers and essential hypertensive patients

To evaluate the renal effects of nisoldipine (N), a dihydropyridine derivative, we have evaluated the variations of blood pressure (BP), heart rate, glomerular filtration rate (GFR), renal plasma flow (RPF), 24-h natriuresis, and renal capacity to excrete an i.v. sodium load (2,000 ml isotonic saline in 4-h) in response to a 4-day course of therapy with placebo (P) and N in six normotensive volunteers and six mild-to-moderate essential hypertensive patients. Both volunteers and patients were studied on two constant diets (20 and 150 mEq of sodium daily). No parameters changed after P. On the contrary, N induced a significant fall of BP (p less than 0.01) in the group of patients but not in volunteers. In both groups RPF and GFR increased significantly (p less than 0.05-0.01) while on a low sodium intake but remained constant when sodium intake was high. In the two groups studied, nisoldipine exhibited natriuretic properties manifested by an increase in the 24-h output of sodium as well as by an increased renal capacity to excrete the i.v. sodium load. These natriuretic properties were present in both situations of sodium load and could be facilitated by the change in renal hemodynamics observed when the intake of sodium was low.

Persistence of the natriuretic effect of calcium entry blockers

In order to elucidate whether or not the natriuretic properties of calcium entry blockers persist during the long-term administration of the drug, we have investigated the renal capacity to excrete an intravenous sodium load (2,000 ml of isotonic saline in 4 h) in a group of eight mild to moderate essential hypertensive patients, before and after 1, 8, and 24 weeks of treatment with nitrendipine. The following parameters were measured before and hourly during saline infusion: blood pressure, and plasma and urine sodium and potassium. For 5 days prior to the performance of the test, the patients received a diet containing 120 mEq of sodium daily. Nitrendipine induced a significant fall of both systolic and diastolic blood pressure (p less than 0.05-0.01) that was maintained throughout the study. A significant increase of the cumulative renal sodium output (microEq/min/h) was observed after 1, 8, and 24 weeks (p less than 0.05-0.001) of therapy with the calcium entry blocker. Meanwhile, plasma sodium and potassium and the kaliuresis did not change significantly. These results indicate that the natriuretic effect of calcium entry blockers is still present after long-term treatment.