Platelet function in whole-blood donors is impaired: the effects of painkillers

BACKGROUND

Aspirin (ASA) or non-aspirin-like nonsteroidal anti-inflammatory drugs (NSAIDs) influence platelet (PLT) function by inhibiting cyclooxygenase enzymes. In this study, the aim was to address the use of ASA or NSAIDs before donation and the effect on PLT function.

STUDY DESIGN AND METHODS

Donors were asked questions about recent use of ASA or NSAIDs. Furthermore, PLT function was evaluated by measurement of the closure time (CT) in a PLT function analyzer (PFA-100, Dade Behring) and by aggregometry (response to ADP or arachidonic acid [AA]).

RESULTS

Of 100 questioned donors, 22 percent had used ASA (n = 4), NSAIDs (n = 6), or paracetamol (n = 12) before donation. Upon assessment of the PLT function in the PFA-100, 27 donors showed values of greater than 180 seconds, indicative of impaired PLT function. Of these, only 7 had used pain killers before donation. Furthermore, 15 of 22 users had normal CTs. Aggregation after stimulation with AA was absent in 33 PLT-rich samples. Again only 8 had reported use of ASA (3), NSAIDs (1), or paracetamol (4). Of the 22 users, 14 had normal AA aggregation responses. All donor samples showed ADP-induced aggregation, indicating PLT integrity. There was no difference between the group of donors who reported the intake of ASA or NSAIDs and the group of donors who did not with respect to the tested PLT function assays.

CONCLUSION

It is concluded that there is a considerable group of donors that use PLT-influencing medication before donation. A relation between the reported use and impaired PLT function in blood donors could not be established, however. Impaired PLT function as tested may have other causes than intake of ASA or NSAIDs.

Evaluation of an automated test ordering and feedback system for general practitioners in daily practice

OBJECTIVE

To evaluate the use of an automated test ordering and feedback system (named GRIF) in daily practice. The system produces recommendations to general practitioners (GPs) to improve the application of accepted practice guidelines for test ordering.

METHODS

A randomised controlled trial with balanced block design was carried out in general practices in two regions of the Netherlands from August 2000 to July 2001. We implemented the GRIF system on the workstations at the offices of the participating GPs. The GPs (n=11) were asked to use GRIF during patient consultation instead of filling in the paper request form. The system displayed critical comments about their non-adherence to the guidelines as apparent from the request forms.

RESULTS

The median time of producing the comments plus the response time of the GP was 13s. Of the 2780 presented recommendations, 4.3% were accepted. Advice of the GRIF system that presents a concrete test to request in a particular situation is adhered to most frequently. Finally, there seems to be a decrease of accepted comments over the trial period.

CONCLUSION

Computerised recommendations should contain, if possible, suggestions for alternative tests to improve the application of these recommendations. Furthermore, creative solutions must be developed to avoid that GPs get used to the recommendations of critiquing systems and to stimulate a better adherence to these recommendations.

Coagulation and fibrinolysis in inflammatory bowel disease and in giant cell arteritis

BACKGROUND

In inflammatory bowel disease (IBD), gut microvascular thrombosis as well as thromboembolic complications have repeatedly been observed. We examined the long-term course of markers of coagulation and fibrinolysis in relation to clinical disease activity.

MATERIALS AND METHODS

In a prospective study, prothrombin fragment 1 and 2 (F1.2), thrombin-antithrombin complex (TAT), antithrombin, D-dimer, plasmin-alpha(2)-antiplasmin complex (PAP) and plasminogen activator inhibitor-1 (PAI-1) were measured in 20 patients with Crohn's disease (CD), 18 with ulcerative colitis (UC), and 19 with giant cell arteritis during active and inactive disease, as well as in 51 controls without inflammation.

RESULTS

Levels of F1.2, TAT, D-dimer, PAP and PAI-1 were significantly higher in active versus inactive CD and UC. However, even after 12 months of follow-up, in CD and UC the mean levels of F1.2, D-dimer and PAP were significantly higher than the levels of the controls.

CONCLUSIONS

Levels of F1.2, D-dimer and PAP were markedly raised for a long time in clinically inactive IBD, underlining a chronic state of hypercoagulation and enhanced fibrinolysis.

The reliability of assessing the appropriateness of requested diagnostic tests

Despite a poor reliability, peer assessment is the traditional method to assess the appropriateness of health care activities. This article describes the reliability of the human assessment of the appropriateness of diagnostic tests requests. The authors used a random selection of 1217 tests from 253 request forms submitted by general practitioners in the Maastricht region of The Netherlands. Three reviewers independently assessed the appropriateness of each requested test. Interrater kappa values ranged from 0.33 to 0.42, and kappa values of intrarater agreement ranged from 0.48 to 0.68. The joint reliability coefficient of the 3 reviewers was 0.66. This reliability is sufficient to review test ordering over a series of cases but is not sufficient to make case-by-case assessments. Sixteen reviewers are needed to obtain a joint reliability of 0.95. The authors conclude that there is substantial variation in assessment concerning what is an appropriately requested diagnostic test and that this feedback method is not reliable enough to make a case-by-case assessment. Computer support maybe beneficial to support and make the process of peer review more uniform.