Sphincter of Oddi manometry: is timing everything?

To determine if cholangiography has an effect on sphincter of Oddi (SO) activity, a prospective study was conducted. Twenty-five patients with suspected SO dysfunction underwent biliary SO manometry (SOM). According to the modified Geenen-Hogan criteria, 12 were classified as biliary type III, seven were biliary type II, and six had idiopathic pancreatitis. Patients were sedated with i.v. medications acknowledged as not affecting biliary basal sphincter pressures, including diazepam, droperidol, and meperidine. Conventional station pull-through manometry of the biliary part of the sphincter was performed before and after contrast injections of the biliary system.In this study group, the mean basal sphincter pressure was not significantly altered by contrast injection (52.9 ± 42.1 mm Hg before vs 55.1 ± 38.1 mm Hg after, p = 0.52). In addition, there was concordance (normal vs abnormal) between basal sphincter pressure before and basal sphincter pressure after contrast injection in 24 of 25 patients (96%). Furthermore, when patients were stratified into subgroups (elevated or normal SO basal pressure, use of a guidewire, meperidine administration, prior biliary sphincterotomy, gallbladder removed or in situ, and length of the interval between the end of contrast injection and the second pull-through), cholangiography did not significantly alter postinjection basal pressures. Finally, in 10 patients the quality and length of the SOM tracing were good enough to allow assessment of phasic SO activity. The phasic pressure wave frequency, amplitude, and duration were in the normal range before and after contrast injection.The authors concluded that cholangiography immediately before SOM infrequently alters SO basal pressure. With respect to clinical practice, the authors advocated the strategy of performing cholangiography before SOM, recognizing that if structural lesions are identified (e.g., stones, tumors), SOM can be avoided.     

Health Assessment Questionnaire modifications: is standardisation needed?

BACKGROUND: Physical disability is part of the end point measures in rheumatoid arthritis clinical trials. The Stanford Health Assessment Questionnaire Disability Index (HAQ DI) is often used for this purpose but lacks international uniformity owing to variations in the translated and adapted questionnaires and variations in its calculation. To study the consequences of these variations the previous Dutch HAQ (HAQ90) was revised, resulting in a new Dutch HAQ (HAQ99). OBJECTIVE: To compare DI scores from the two versions, and to study the consequences of applying different calculation methods for the DI score. METHODS: 78 patients completed both the HAQ99 and the HAQ90. To compare the use of different category score calculation methods a post hoc analysis on prospectively collected data obtained in clinical trials was performed. RESULTS: No statistically significant differences were observed between the DI scores of the HAQ90 and the HAQ99 using the alternative method (that is, without correcting for aid and devices). However, correcting for the use of aid or devices or not did result in statistically significant different DI scores. The systematic shift when using the maximum or mean item score for calculation of the category score resulted in non-comparable absolute DI scores. CONCLUSION: The use of HAQ DI questionnaires with different numbers of items and/or categories does not hinder international comparability, except when these variations interfere with the calculation method of the DI (as in the case of questionnaires without a section correcting for devices). For the sake of international uniformity the HAQ or any validated translation should be used and calculated in a standard way, including correcting for the use of aid and devices, and taking the maximum within each category as the category score.     

How much blood is needed?

Demographic changes in developed countries as their populations age lead to a steady increase in the consumption of standard blood components. Complex therapeutic procedures like haematopoietic stem cell transplantation, cardiovascular surgery and solid organ transplantation are options for an increasing proportion of older patients nowadays. This trend is likely to continue in coming years. On the other hand, novel aspects in transplant regimens, therapies for malignant diseases, surgical procedures and perioperative patient management have led to a moderate decrease in blood product consumption per individual procedure. The ageing of populations in developed countries, intra-society changes in the attitude towards blood donation as an important altruistic behaviour and the overall alterations in our societies will lead to a decline in regular blood donations over the next decades in many developed countries. Artificial blood substitutes or in vitro stem cell-derived blood components might also become alternatives in the future. However, such substitutes are still in early stages of development and will therefore probably not alleviate this problem within the next few years. Taken together, a declining donation rate and an increase in the consumption of blood components require novel approaches on both sides of the blood supply chain. Different blood donor groups require specific approaches and, for example, inactive or deferred donors must be re-activated. Optimal use of blood components requires even more attention.     

Diagnosis of pulmonary embolism: when is imaging needed?

Recent advances in the management of patients with suspected pulmonary embolism have improved diagnostic accuracy and made management algorithms safer and more accessible. Ongoing clinical trials are evaluating whether these diagnostic processes can be made even simpler and less expensive. It is now possible to identify low-risk patients with suspected pulmonary embolism in whom imaging procedures can be avoided altogether.     

The number needed to harm: is it too optimistic?

The number needed to treat (NNT) to prevent one adverse outcome event is a useful measure of clinical trial results and represents the therapeutic effort required to realize a specific clinical benefit. With many therapies, there are both positive and negative consequences. Analogous to the NNT, there is the number needed to harm (NNH), which is the reciprocal of the absolute risk increase in situations where the experimental treatment harms more patients then the control treatment. The NNH is the number of patients who, if they received the experimental treatment, would lead to one additional person being harmed compared with patients who receive the control treatment. The NNH may, however, provide an optimistic measure of the true risks caused by therapy.     

Two-stage testing in microarray analysis: what is gained?

Microarray technology for gene expression studies offers powerful new technology for understanding changes in gene expression as a function of other observable or manipulable variables. However, microarrays also pose a number of new challenges. One of the most prominent of these is the difficulty in establishing a procedure for declaring whether a gene's expression level is associated with the independent variable that offers reasonable and specifiable false-positive (type 1 error) and false-negative (type 2 error) rates. A recent article described a two-stage testing procedure to address these goals. However, information was not provided to indicate whether this procedure would or would not meet its objectives. Herein, we show mathematically that the two-stage procedure proposed does not provide benefits in terms of minimizing false-negatives while controlling the false-positive rate relative to standard single-stage testing. Therefore, investigators are encouraged to consider alternative analytic approaches.