Correction: Smart Data Collection for the Assessment of Treatment Effects in Irritable Bowel Syndrome: Observational Study (Preprint)

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Low Quality of Reports on Blood Pressure in Patients Adrenalectomized for Unilateral Primary Aldosteronism

Context Adrenalectomy is the preferred treatment for unilateral primary aldosteronism but the results of long-term control of blood pressure (BP) are far from optimal. One possible explanation relates to the quality of the assessment of treatment effects on BP. Purpose of the study To examine the quality of reporting BP measurements in studies assessing the outcome of adrenalectomy on BP. Methods We conducted a systematic review searching 3 databases (PubMed, EMBASE, Web of Science) for articles published from January 1, 1990, onwards. Sixty-six studies, each reporting on more than 50 adrenalectomized patients, were eligible for full analysis. Results In 37 of the analyzed 66 studies (56.1%) BP values both before and after adrenalectomy were reported. In 19.7% (13/66) of the studies the method of BP measurement was described. The number of visits and number of BP recordings per visit on which BP results were based were reported in <15% of papers. The criteria for the diagnosis of hypertension were described in 72.7% (48/66) of the studies. The used definitions of improvement of BP control after adrenalectomy were variable, with 84.8% of the studies not providing any quantitative criteria to define reduction in BP. Conclusion We conclude that the quality of reporting on BP control after adrenalectomy for primary aldosteronism shows substantial deficiencies and inconsistencies, thus impacting negatively on accurate assessment of effects of adrenalectomy on BP control. Future studies should adhere to accepted recommendations of correct BP measurement and should provide detailed description of the methods used for BP measurement.

The nocebo effect as a source of bias in the assessment of treatment effects

The term nocebo effect refers to the harmful outcomes that result from people’s negative beliefs, anticipations, or experiences related to the treatment rather than the pharmacological properties of the treatment. These outcomes may include a worsening of symptoms, a lack of expected improvement, or adverse events, and they may occur after the active treatment and the placebo that is supposed to imitate it. The nocebo effect is always unwanted and may distort estimates of treatment effectiveness and safety; moreover, it may cause discontinuation of therapy or withdrawal from a trial. The nocebo effect may be unintentionally evoked by the explanations given by healthcare professionals during a clinical consultation or consent procedures, or by information from other patients, the media, or the Internet. Moreover, it may be a consequence of previous bad experiences with the treatment, through learning and conditioning, and the conditioning may happen without patients’ conscious awareness. In trial settings, a study design, for example lack of blinding, may introduce bias from the nocebo effect. Unlike the placebo effect, which is usually taken into consideration while interpreting treatment outcomes and controlled for in clinical trials, the nocebo effect is under-recognised by clinical researchers and clinicians. This is worrying, because the nocebo phenomenon is common and may have potentially negative consequences for the results of clinical treatment and trials. It is therefore important that doctors and medical researchers consider any potential nocebo effect while assessing the treatment effect and try to minimise it through careful choice and phrasing of treatment-related information given to patients.