[COVID-19 and medical publications: How three articles have influenced the media and public decisions in France]

Cet article détaille le processus et les aléas de publication de trois articles se rapportant au SARS-CoV-2 et à la maladie qu’il provoque (COVID-19). Ces trois articles ont été publiés à un mois d’intervalle, entre mars et mai 2020. Leur médiatisation a conduit les autorités de santé françaises à intervenir. Notre article ne s’intéresse pas et n’évalue pas la qualité scientifique des articles présentés, mais a pour unique objectif d’ouvrir la réflexion sur la publication médicale. En décrivant ces trois cas particuliers, il soulève des questions sur la rétractation des articles, l’évaluation par les pairs, la prépublication, la paternité des articles, et la diffusion des informations scientifiques médicales y compris via les médias de masse. Il discute des nouveaux modes d’édition qui se profilent et de la diffusion des informations publiées en recherche clinique.

A new strategy for screening infectious diseases amongst migrants: the STRADA study

Background

In France, the prevalence of HIV, HBV and HCV is high amongst migrants and widespread testing is recommended. All legal migrants in France undergo a mandatory medical check-up at the immigration center (OFII). This check-up is an opportunity to offer rapid HIV and hepatitis testing. A screening questionnaire for risk factors (TROD screen) has been developed and could help target the screening offer. The objective of the STRADA study is to evaluate the efficacy of a screening strategy for infectious diseases (Tuberculosis, HIV, HBV and HCV) based on risk-factor questionnaires amongst migrants during the medical check-up.

Methods

STRADA is a prospective, multicenter, observational study with two parts: tuberculosis screening (evaluation of a screening questionnaire) and HIV, HBV and HCV screening. For that part we have created a risk-based questionnaire for those three infections. In the first phase of the study, all migrants eligible are offered a screening, the TROD screen questionnaire. In the second phase, the screening offered on the basis of country of origin will be compared to the screening offered on the basis of the risk factor questionnaire. Finally, a cost-effectiveness study will be performed. During the informed consent process, participants are informed that the study is voluntary and independent from the residence permit.

Preliminary results

A risk-based questionnaire has been created and translated in 10 languages. The screening has been implemented in 20 immigration centers in France. In April 2019, 35,000 participants have answered the TB screen and 8,250 have been screened for at least one of the three virus.

Discussion

This study will determine the acceptability, performance, utility, costs and impact of a targeted optimized screening strategy for migrants in France. The presence of infectious diseases amongst migrants is a major public health issue. STRADA is an innovative initiative that has the potential to improve screening.

The Intestinal Gas Questionnaire: development of a new instrument for measuring gas-related symptoms and their impact on daily life

BACKGROUND

Although gas-related symptoms (GRS) are common and intrusive, there are no questionnaires to quantitate this problem. This study aimed to develop an instrument to rectify this gap in our knowledge.

METHODS

Concepts were initially identified from the literature and interviews with gastroenterologists. Exploratory one-to-one interviews and focus groups with irritable bowel syndrome (IBS) patients (n = 28) and non-IBS subjects (n = 27) with GRS were conducted in UK, France, and Spain leading to a conceptual framework for the questionnaire. Last, iterative rounds of cognitive debriefing were performed with IBS (n = 16) and non-IBS subjects (n = 14).

KEY RESULTS

From the first three steps, nine GRS (bloating, distension, flatulence, odorous flatulence, difficult gas evacuation, stomach rumbling, belching, bad breath, and abdominal movement) were identified although abdominal movement was subsequently excluded. Twelve quality of life domains affected by these symptoms were identified as: Clothing, emotional, physical appearance, diet, daily living, work, social life, physical activity, relationships, sex life, sleep, and cognitive function. A 24-h recall for symptoms and a 7-day recall for impact assessment were supported by the qualitative findings. Cognitive debriefing confirmed the understanding of the instrument. Across the three languages, the instrument was conceptually and linguistically consistent.

CONCLUSIONS & INFERENCES

The International Gas Questionnaire is a 2-part instrument, developed rigorously and simultaneously in three languages assessing seven symptoms (17 items) and their impact on 12 domains (26 items) in IBS and general population. It is now undergoing psychometric validation and should provide a unique tool for epidemiological surveys and clinical trials for developing new treatments for these symptoms.

The minimally important difference in the Rhinoconjunctivitis Total Symptom Score in grass-pollen-induced allergic rhinoconjunctivitis

BACKGROUND

The minimally important difference (MID) has been defined as the smallest improvement considered worthwhile by a patient. The MID has not been estimated for the Rhinoconjunctivitis Total Symptom Score (RTSS).

METHODS

In a prospective multicentre study, patients consulting for grass-pollen-induced allergic rhinitis (AR) recorded a 15-point global rating of change scale (GRCS) score and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score on a weekly basis and the individual symptom scores comprising the RTSS on a daily basis over two consecutive weeks. The MID in the RTSS was determined with anchor-based methods (using the GRCS and the RQLQ) and a distribution-based method [based on the RTSS' standard deviation (SD)].

RESULTS

The study population comprised 806 patients (253 children, 250 adolescents and 303 adults). During the first week of the study, the mean ± SD RTSSs for these age groups were 6.5 ± 3.3, 6.8 ± 3.4 and 7.0 ± 3.4, respectively. For an improvement of 2 points in the GRCS or 0.5 points in the RQLQ score, the regression analysis yielded MIDs in the RTSS of 1.24 ± 0.17 and 1.12 ± 0.14 in children, 1.33 ± 0.14 and 1.20 ± 0.13 in adolescents and 1.13 ± 0.14 and 0.89 ± 0.12 in adults, respectively. When applying distribution-based methods, the MID ranged from 1.09 to 1.13 (based on 0.33 SDs of the first-week RTSS) and from 1.22 to 1.40 (based on 0.5 SDs of the difference in RTSSs between the first and second weeks).

CONCLUSION

The MID in the RTSS was consistently estimated as 1.1-1.3 (and could conceivably be rounded to 1) in patients with grass-pollen-induced AR.

Validation of a self-questionnaire for assessing the control of allergic rhinitis

BACKGROUND

Allergic rhinitis affects the lives of patients for whom discomfort is, in most cases, significantly improved by pharmacological treatment.

OBJECTIVE

To develop and validate a self-assessment global score for allergic rhinitis control (five items scored from 1 to 5 assessing the rhinitis over the 2 previous weeks).

METHODS

Study of acceptability, reliability, validity and sensitivity to change during a prospective observational study in 902 patients selected by 411 general practitioners or allergists.

RESULTS

The score correlated significantly to the clinical picture and to the impact of the rhinitis on social and sports activities at inclusion (P<0.0001). A significant improvement in the score was observed after 15 days of treatment: 14.9 ± 4.0 at inclusion and 21.5 ± 2.9 at re-evaluation after 15 days of treatment (P<0.0001). Using receiver operating characteristics curve, a score of 20 was the cut-off for poor vs. well-controlled rhinitis; a score strictly higher than 20 (best being 25) had a sensitivity of 67%, a specificity of 82%, a negative predictive value of 32% and a positive predictive value of 95%.

CONCLUSION AND CLINICAL RELEVANCE

The self-assessment score for allergic rhinitis control appeared to be sensitive to change and correlated to the clinical expression of rhinitis and also to its involvement with treatment. These results suggest that this self-completion questionnaire could be used in daily practice at each consultation to determine, in a standardized manner, the level of control of the allergic rhinitis of an individual patient.

[How can an effective drug to treat irritable bowel syndrome be successfully developed?]

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent disorder, and although the pharmaceutical industry knows the potential fallout of a successful drug launch in this area, effective drug treatments are rare.

AIM

To give an overview of the main factors interfering with the development of IBS drugs and to provide pertinent methodological indications to improve their investigation in clinical trials.

RESULTS

Developing IBS drugs remains a major challenge, as numerous factors, related or unrelated to the nature of the disease itself, interfere with the demonstration of efficacy : the multiplicity of physiopathological mechanisms, wide variation in symptoms across patients and over time, associated psychological traits and environmental aspects, and a very significant placebo effect. There can be no question of developing drugs to target a single receptor in the hope of thereby impacting the whole range of factors involved in the genesis of IBS symptoms. Drug safety is, moreover, a prime consideration, given that this pathology, while certainly disabling, is not life-threatening. If a significant difference between a new treatment and placebo is to be demonstrated on a clinical trial, inclusion and efficacy criteria and study treatment duration must be predefined very precisely. The primary endpoint is abdominal pain, but the assessment of relief of the patient's symptoms has been also recommended, even if there is as yet no consensus as to its definition. The impact of a new IBS drug on patient's quality of life is an important secondary endpoint.

CONCLUSION

In IBS more, perhaps, than in other pathologies, study design needs very careful consideration if new IBS drug trials are to be conclusive. However, some critical methodological issues (e.g., definite primary endpoint, interpretation of results, and definition of responders) are still unresolved.

[How can an effective drug to treat irritable bowel syndrome be successfully developed?]

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent disorder, and although the pharmaceutical industry knows the potential fallout of a successful drug launch in this area, effective drug treatments are rare.

AIM

To give an overview of the main factors interfering with the development of IBS drugs and to provide pertinent methodological indications to improve their investigation in clinical trials.

RESULTS

Developing IBS drugs remains a major challenge, as numerous factors, related or unrelated to the nature of the disease itself, interfere with the demonstration of efficacy : the multiplicity of physiopathological mechanisms, wide variation in symptoms across patients and over time, associated psychological traits and environmental aspects, and a very significant placebo effect. There can be no question of developing drugs to target a single receptor in the hope of thereby impacting the whole range of factors involved in the genesis of IBS symptoms. Drug safety is, moreover, a prime consideration, given that this pathology, while certainly disabling, is not life-threatening. If a significant difference between a new treatment and placebo is to be demonstrated on a clinical trial, inclusion and efficacy criteria and study treatment duration must be predefined very precisely. The primary endpoint is abdominal pain, but the assessment of relief of the patient's symptoms has been also recommended, even if there is as yet no consensus as to its definition. The impact of a new IBS drug on patient's quality of life is an important secondary endpoint.

CONCLUSION

In IBS more, perhaps, than in other pathologies, study design needs very careful consideration if new IBS drug trials are to be conclusive. However, some critical methodological issues (e.g., definite primary endpoint, interpretation of results, and definition of responders) are still unresolved.

International validation of a health-related quality of life questionnaire in patients with erosive gastro-oesophageal reflux disease

BACKGROUND

Although erosive gastro-oesophageal reflux disease (GERD) is a highly prevalent condition, there is no specific, valid, reliable and sensitive questionnaire that allows evaluating treatment-induced changes in health-related quality of life (HRQoL).

AIM

To design a self-administered questionnaire, the GERD Analyzer (GERDyzer), for use in clinical studies.

METHODS

The GERDyzer comprises 10 dimensions each illustrated by pictogram-like drawings, simplifying communication with the patients. Self-assessment is performed by 100 mm Visual Analogue Scales. For validation, a 5-week clinical trial involving 395 patients (per-protocol) with oesophagitis was conducted. Patients were treated with pantoprazole (40 mg o.d.) for 28 days. Psychometric analyses included internal consistency, test-retest reliability, responsiveness and construct validity.

RESULTS

Factor analysis showed consistency of the dimensions and no reduction was necessary. Validation of GERDyzer indicated high internal consistency (Cronbach's alpha = 0.95) and test-retest reliability (intraclass correlation coefficient =0.91). Responsiveness of the total score expressed by nonparametric effect size was 1.38. Comparison of scores with other questionnaires resulted in logical correlation levels depending on the respected concepts measured. Conclusions GERDyzer proved to be highly valid, reproducible and responsive. It allows reliably assessing treatment-induced changes in HRQoL in erosive GERD.

Validation of a questionnaire for assessment of asthma patient knowledge and behaviour

BACKGROUND

For several years, educational programmes have been highlighted because care success depends on patient's knowledge and patient's asthma management. However, no tool is available to assess change in patient knowledge and behaviour before and after completing an educational programme.

OBJECTIVE

To validate a questionnaire measuring the knowledge and behaviour of asthmatics participating in an educational programme and to gauge the benefit of such a programme.

METHODS

The Asthma Behaviour Change (ABC) questionnaire was generated from literature, patient surveys and clinical situations. It was organized in eight dimensions assessing patient behaviour in seven different clinical situations and two assessing patient (pathophysiology and therapeutic) knowledge. A total of 139 asthmatics filled out the questionnaire before, during and after the educational programme.

RESULTS

The principal component analysis confirmed the structure empirically made by clinical situations. Internal consistency analysis yielded high Cronbach's alpha values. Different dimensions and the two global scores were able to discriminate patients according to asthma severity. Finally, the effect size of difference before and after educational programme was at least 0.47, and was larger than 0.74 for both global behaviour and knowledge scores. The difference between visit 1 and 3 for global behaviour and knowledge scores reached 18.84 +/- 20.83 (P < 0.001, 95% CI: 13.18-24.43) and 11.06 +/- 14.98 (P < 0.001, 95% CI: 7.10-15.03), respectively.

CONCLUSION

ABC questionnaire is a valid tool to assess asthmatics' knowledge and behaviour. Furthermore, this study confirmed that educational programmes lead to better awareness of asthma by patients.

Systematic review: health-related quality of life (HRQOL) questionnaires in gastro-oesophageal reflux disease

BACKGROUND

Although gastro-oesophageal reflux disease (GERD) has a well-established pathophysiology, the impact of GERD symptoms on the patients' quality of life can be profound. Therefore, health-related quality of life (HRQOL) questionnaires have become standard instruments to evaluate the effect of treatment in clinical trials.

AIM

To evaluate the reliability, validity and responsiveness of available GERD-specific HRQOL.

METHODS

A systematic literature search using the Medical Subject Headings terms: 'Gastro-oesophageal reflux', 'Heartburn' and 'Oesophagitis' with 'quality of life' and 'questionnaires' was preformed to identify the available HRQOL questionnaires. To analyse the psychometric properties of the respective tools, the actual guidelines for the use of patient-reported outcomes in clinical trials were applied.

RESULTS

We identified five GERD-specific HRQOL questionnaires but none of them fulfilled all quality criteria; either they did not meet the actual standards for psychometric properties (HBQOL, GERD-HRQL, Jasani et al.Aust Fam Physician 1999; 28: 515), or were impracticable to use in clinical trials. The generic and hybrid instruments lack specificity and sensitivity and were not designed for treatment evaluation in GERD patients.

CONCLUSION

There is need for a new evaluative tool in the assessment of HRQOL during GERD therapy.

Effect of a fermented milk containing Bifidobacterium animalis DN-173 010 on the health-related quality of life and symptoms in irritable bowel syndrome in adults in primary care: a multicentre, randomized, double-blind, controlled trial

BACKGROUND

Health-related quality of life (HRQoL) has been rarely evaluated as a primary endpoint in the assessment of the effect of probiotics on the irritable bowel syndrome (IBS).

AIM

To study the effects of fermented milk containing Bifidobacterium animalis DN-173 010 and yoghurt strains on the IBS in a multicentre, double-blind, controlled trial.

METHODS

A total of 274 primary care adults with constipation-predominant IBS (Rome II) were randomized to consume for 6 weeks either the test fermented milk or a heat-treated yoghurt (control). HRQoL and digestive symptoms were assessed after 3 and 6 weeks on an intention-to-treat population of 267 subjects.

RESULTS

The HRQoL discomfort score, the primary endpoint, improved (P < 0.001) in both groups at weeks 3 and 6. The responder rate for the HRQoL discomfort score was higher (65.2 vs. 47.7%, P < 0.005), as was the decrease in bloating score [0.56 +/- (s.d.)1.01 vs. 0.31 +/- 0.87, P = 0.03], at week 3 in the test vs. the control group. In those subjects with <3 stools/week, stool frequency increased (P < 0.001) over 6 weeks in the test vs. control group.

CONCLUSIONS

This study suggests a beneficial effect of a probiotic food on discomfort HRQoL score and bloating in constipation-predominant IBS, and on stool frequency in subjects with <3 stools/week.

Acute exacerbation of pain in irritable bowel syndrome: efficacy of phloroglucinol/trimethylphloroglucinol. A randomized, double-blind, placebo-controlled study

BACKGROUND

Abdominal pain is the predominant symptom in irritable bowel syndrome patients. Phloroglucinol and its methylated derivative are antispasmodic agents acting on smooth muscle.

AIM

To evaluate the efficacy of phloroglucinol/trimethylphloroglucinol on pain intensity during an acute exacerbation of pain of irritable bowel syndrome over a 1-week period treatment.

METHODS

Irritable bowel syndrome Rome II patients seeking medical advice for an acute exacerbation of abdominal pain were randomized to phloroglucinol/trimethylphloroglucinol (62.2 mg P + 80 mg TMP) two pills three times daily or placebo for 7 days. Patients were included if they had a pain with a minimal intensity of 40 on a 100-mm visual analogue scale, and if pain occurred at least 2 days during the week previous inclusion.

RESULTS

Three hundred and seven patients were included by 78 general practitioners. The intent-to-treat population included 300 patients, aged of 46.9 +/- 14.8 years (73% female). The relative decrease of pain intensity at day 7 was 57.8 +/- 31.7% vs. 46.3 +/- 34.7% (Delta = 11.5 +/- 3.8%, [CI(95%): 4.0 ; 19.1], P = 0.0029) and the percentage of patients with at least a 50% decrease of pain intensity was 62% vs. 47% (Delta = 15.3 +/- 5.7%, [CI(95%): 4.1 ; 26.5], P = 0.0078) in phloroglucinol/trimethylphloroglucinol and placebo groups, respectively.

CONCLUSIONS

A 1-week phloroglucinol/trimethylphloroglucinol treatment significantly reduces pain intensity in irritable bowel syndrome patients consulting their general practitioners for pain exacerbation.

Impact of pain in health related quality of life of patients with systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) has an heterogenous clinical pattern, with variable organ involvement and degrees of severity. Like in other rheumatic diseases, the self-questionnaires have been used to evaluate SSc globally. The aim of the study is as to evaluate the quality of life (QoL) in patients with either diffuse or limited SSc, and to examine the impact of pain on the QoL scores.

METHODS

Patients with SSc, either diffuse or limited SSc, were included in a cross-sectional study. The QoL was evaluated with the short-form 36 (SF-36) and the functional repercussion with the SSc-modified Health Assessment Questionnaire (S-HAQ).

RESULTS

A total of 89 patients (67 with diffuse and 22 with limited SSc) were included. The SF-36 score values were lower in SSc patients than those reported in the general population. The physical component scores (PCS) of the SF-36 was significantly worse in diffuse compared with limited SSc (P < 0.05). The PCS was significantly negatively related to the number of clinical manifestations (ANOVA, P < 0.0001). The mental component score (MCS) was not influenced by the type of SSc or the number of clinical manifestations presented by the patient. The QoL of SSc patients was highly correlated with pain (R = 0.69) and disability (R = 0.70). Interestingly, the QoL of SSc patients was only slightly correlated with cutaneous (R = 0.42) and pulmonary involvement (R = 0.57).

CONCLUSION

The QoL of patients with SSc is strongly influenced by the type of SSc, the burden of clinical manifestations, the functional disability and by the pain, whatever its cause. The treatment of pain should be considered as priority to improve the QoL of SSc patients.

Validation of French version of the Scleroderma Health Assessment Questionnaire (SSc HAQ)

The modified Scleroderma Health Assessment Questionnaire (SSc HAQ) is a functional score to assess systemic sclerosis (SSc) comprising the HAQ disease index (HAQ-DI) plus five specific visual analogue scales (VAS). Since it was validated in English-speaking patients only, its general use in any other language necessitates prior cross-cultural adaptation and validation. We designed this study to assess its value in French-speaking patients and to validate the French version according to international recommendations. We elaborated a French version using the "forward-backward" method. We then validated its psychometric properties with 100 consecutive SSc French-speaking patients who had undergone simultaneous clinical and paraclinical examination. In addition, we calculated the SSc HAQ score, a new outcome measure, which is obtained by pooling the eight domains from the HAQ-DI with the five organ VAS. Our study confirmed the psychometric properties of the SSc HAQ in non-English-speaking patients with (a) structural validity: the major component analysis, performed on the HAQ-DI and the five VAS, yielding a two-factor structure; (b) convergent validity: with high correlation coefficients between the SSc HAQ score and the physical component score of the SF-36 (r=-0.74, p<0.0001); (c) discriminant validity: the SSc HAQ score was better in patients with limited than with diffuse SSc (0.5+/-0.5 vs 1.1+/-0.7, respectively, p<0.0001) in relation to the number of clinical involvements; (d) reproducibility was high using the test-retest procedure (r=0.98). This study showed the value of the SSc HAQ, which is a simple, discriminant, reproducible self-administered questionnaire to evaluate French-speaking SSc patients. In addition, we suggest the use of a new outcome measure, the SSc HAQ score, to assess this systemic disease more accurately.

Évaluation de la qualité de vie par le MOS-SF36 dans la sclérodermie systémique

OBJECTIVE

To investigate the metric properties and the validity of the Medical Outcome Study Short Form 36 (SF-36), a questionnaire to assess the quality of life, in patients with either diffuse or limited systemic sclerosis (SS), and to examine the effect of the disease on quality of life.

METHODS

Cross sectional study of 86 patients with a SS (64 diffuse SS, 22 limited SS). Disease severity was assessed by clinical examination, pulmonary functional tests and Health Assessment Questionnaire (HAQ) modified for scleroderma.

RESULTS

The SF-36 scores values were lower in diffuse than in limited sclérodermie systémique. The Physical Component Score was worse in patients with than without any clinical involvement. This score increased in relation with the number of clinical involvements. The quality of life of patients with SS was correlated to its functional repercussion.

CONCLUSION

The quality of life in SS patients is correlated with the clinical severity of the disease. The use of SF-36 to measure the quality of life is useful for the clinical evaluation of patients with SS.

Study design in osteoporosis: a European perspective

The advent of effective agents for the treatment of osteoporosis has led to the view that placebo-controlled trials to test new agents for efficacy are no longer appropriate. Rather, studies of superiority, equivalence, or non-inferiority have been recommended. Such studies require very large sample sizes, and the burden of osteoporotic fracture in a trial setting is substantially increased. Studies of equivalence cannot be unambiguously interpreted because the variance in effect of active comparator agents is too large in osteoporosis. If fracture studies are required by regulatory agencies, there is still a requirement for placebo-controlled studies, although perhaps of shorter duration than demanded at present.

D-dimer: a characteristic of the coagulation state of each patient with chronic atrial fibrillation

BACKGROUND AND OBJECTIVE

It is accepted that patients with atrial fibrillation (AF) are characterised by increased levels of plasmatic D-dimers, with a wide inter-individual variability depending on the patients and therapeutic characteristics, but it has not been established if this level was predictive of the risk of arterial thromboembolic event. In order to answer such a question, it has to be established if the D-dimer level in a given patient is characteristic of such a patient (stable over time) if also fluctuating with time (and useless to characterise the patient).

METHODS AND RESULTS

One hundred thirty clinically stable patients with chronic AF were recruited (anticoagulant: group 1, antiaggregant aspirin: group 2, no antithrombotic: group 3). During the follow-up of patients without clinical events (n=63), it is notable that in patients with D-dimer levels <500 ng/ml, these remained <1000 ng/ml, in patients with levels between 500 and 1000 ng/ml, these did not reach 1590 ng/ml, and in those with D-dimers >1000 ng/ml, the levels remained relatively stable. Mean age and D-dimer levels were lower in group 1 (74.4 years and 509.1 ng/ml, respectively) than in group 2 (82.4 years, p=0.0003 and 1015.7 ng/ml, p<0.0001, respectively) and in group 3 (79.3 years and 1289.3 ng/ml, p<0.0001, respectively). The effect of the antithrombotic therapy was independent of the age of patients (p=0.017).

CONCLUSION

D-dimer levels in patients with chronic AF remain in the same range over time. They are lower on anticoagulant therapy than on antiaggregant or no antithrombotic therapy, irrespective of age. Thus, D-dimers appear to be a useful parameter for assessing the degree of hypercoagulability of patients whatever their age.

[Reading a clinical trial report]

To improve medical knowledge by reading clinical trial reports it is necessary to check for the respect of the methodological rules, and to analyze and criticize the results. A control group and a randomisation are always necessary. Double blind assessment, sample size calculation, intention to treat analysis, a unique primary end point are also important. The conclusions of the trial are valid only for the population included and the clinical signification of the results, depending on the control treatment, has to be evaluated. Respect of the reading rules is necessary to assess the reliability of the conclusions, in order to promote evidence-based practice.

Drug-induced diarrhoea

Diarrhoea is a relatively frequent adverse event, accounting for about 7% of all drug adverse effects. More than 700 drugs have been implicated in causing diarrhoea; those most frequently involved are antimicrobials, laxatives, magnesium-containing antacids, lactose- or sorbitol-containing products, nonsteroidal anti-inflammatory drugs, prostaglandins, colchicine, antineoplastics, antiarrhythmic drugs and cholinergic agents. Certain new drugs are likely to induce diarrhoea because of their pharmacodynamic properties; examples include anthraquinone-related agents, alpha-glucosidase inhibitors, lipase inhibitors and cholinesterase inhibitors. Antimicrobials are responsible for 25% of drug-induced diarrhoea. The disease spectrum of antimicrobial-associated diarrhoea ranges from benign diarrhoea to pseudomembranous colitis. Several pathophysiological mechanisms are involved in drug-induced diarrhoea: osmotic diarrhoea, secretory diarrhoea, shortened transit time, exudative diarrhoea and protein-losing enteropathy, and malabsorption or maldigestion of fat and carbohydrates. Often 2 or more mechanisms are present simultaneously. In clinical practice, 2 major types of diarrhoea are seen: acute diarrhoea, which usually appears during the first few days of treatment, and chronic diarrhoea, lasting more than 3 or 4 weeks and which can appear a long time after the start of drug therapy. Both can be severe and poorly tolerated. In a patient presenting with diarrhoea, the medical history is very important, especially the drug history, as it can suggest a diagnosis of drug-induced diarrhoea and thereby avoid multiple diagnostic tests. The clinical examination should cover severity criteria such as fever, rectal emission of blood and mucus, dehydration and bodyweight loss. Establishing a relationship between drug consumption and diarrhoea or colitis can be difficult when the time elapsed between the start of the drug and the onset of symptoms is long, sometimes up to several months or years.

Ethics and clinical trials

The current reference guideline about ethics in clinical trials is the Declaration of Helsinki of human rights in medical research. Three major principles are emphasised: respect of the patient to accept or not to participate in a trial, the constraints and the presumed risks must be acceptable for patients included in a study, and vulnerable subjects should not participate in studies. The investigator is responsible for obtaining a free and well-informed consent from patients before their inclusion in a study. Where possible, a new drug should always first be compared to placebo in order to prove its superiority. Else, a small-sized trial comparing a new drug versus a reference treatment can lead to an erroneous conclusion of absence of difference. Moreover, good results or improvement are obtained in at least 30% of cases with placebo, whatever the disease. The use of placebo is unethical in life-threatening diseases and when an effective proved drug exists. The use of placebo is ethical in severe diseases with no efficient drug, in some severe diseases even when an active reference treatment is available, and in all moderate and functional diseases. In order to detect flawed studies, most journals now ask for any manuscript submitted and reporting results of a randomised clinical trial to join a checklist in order to verify the quality of the trial. Finally, it remains the responsibility of the doctor to decide whether or not a protocol is ethical, to participate or not and to include patients or not.