liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Comparison of prothrombin time (INR) results and main characteristics of patients on warfarin treatment in primary health care centers and anticoagulation clinics
Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Internal Medicine.ORCID iD: 0000-0003-1068-6168
Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
2013 (English)In: BMC Health Services Research, E-ISSN 1472-6963, Vol. 13Article in journal (Refereed) Published
Abstract [en]

Background

Oral anticoagulant therapy is used to prevent thrombosis in patients with atrial fibrillation (AF), venous thrombosis and prosthetic heart valves. The introduction of new therapies emphasizes the need to discern the best practice for the patients remaining on warfarin treatment. This study compares patient characteristics and therapeutic control in two settings managing warfarin treatment: Swedish primary health care centers (PHCC) and specialized anticoagulation clinics (ACC).

Methods

Prothrombin time (PT) test results reported as International Normalized Ratio (INR) were collected for five consecutive days from patients on warfarin treatment; 564 PHCC and 927 ACC patients. Therapeutic control was calculated as PT test results in relation to intended therapeutic range (TR). Mann–Whitney Rank Sum Test and Chi2 test were used for statistical comparisons.

Results

The PHCC patients were older than the ACC patients, 76 v. 70 years (p<0.01) with a predominance of men in both groups. The reasons for treating differed between the groups. Seventy-two percent of PHCC patients and 66% of ACC patients had a PT-INR within the intended TR (p<0.05). Men generally had better results than women (72% v. 63%, p<0.001) and particularly in the PHCC group v. the ACC group (78% v. 69%, p<0.01).

PT-INR above intended TR was significantly more common in the ACC setting, (p<0.05), for women overall (p<0.01), for women in the PHCC setting, and for ACC men (p<0.05).

Conclusions

In this study both settings achieved good therapeutic control of warfarin treatment with a minor advantage for PHCC over ACC, and better results for men, especially in the PHCC setting. As patient characteristics differ between the PHCC and ACC, it is important to conduct further randomized studies to discern the best practice locally for warfarin management also after the introduction of new drugs.

Place, publisher, year, edition, pages
BioMed Central , 2013. Vol. 13
Keywords [en]
Oral anticoagulants, Treatment, Quality control, Warfarin
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-90753DOI: 10.1186/1472-6963-13-85ISI: 000315994100001OAI: oai:DiVA.org:liu-90753DiVA, id: diva2:614699
Note

Funding Agencies|Medical Research Council of Southeast Sweden (FORSS)||

Available from: 2013-04-08 Created: 2013-04-05 Last updated: 2023-10-31Bibliographically approved
In thesis
1. Two worlds, one goal: A Clinician’s Perspective on Laboratory Analyses in Anticoagulant Treatment
Open this publication in new window or tab >>Two worlds, one goal: A Clinician’s Perspective on Laboratory Analyses in Anticoagulant Treatment
2023 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Almost precisely a century ago, in the 1920s and 1930s, cattle bled to death in North America after being fed moldy hay containing sweet clover, the yellow Melilotus officinalis, and the white Melilotus albus. The toxic substance in the hay inhibiting blood coagulation was identified and named dicumarol. Further development resulted in warfarin, an oral anticoagulant that has been used for over 70 years and still is, even though newer direct-acting oral anticoagulants (DOACs) are mainly replacing it. For some patients, warfarin is still the drug of choice. A safe warfarin treatment needs repeated blood sample analysis (PT-INR), and with the new DOACs come new laboratory challenges. The aim of this thesis was to investigate ways laboratory methods can contribute to improving oral anticoagulant treatment. 

Paper I explores genetic variants of the enzyme targeted by warfarin, VKORC1. The result shows that the haplotype VKORC1*2 is the most important of the VKORC1 haplotypes for warfarin dosage, with a lower dose requirement. The VKORC1*2 haplotype was also related to more unstable PT-INR levels. 

Paper II describes a cross-section study comparing warfarin treatment control, as PT-INRs within the intended therapeutic range, in primary health care centers (PHCCs) and specialized anticoagulation clinics (ACCs). Both settings showed good therapeutic control, with at least as good therapeutic control in the PHCCs as in the ACCs. Today, almost all warfarin treatment in our region is centralized to ACCs. 

Paper III focuses on the modification of a point-of-care PT method. A ratio of PT from two different dilutions of each patient sample was calculated and used as an indirect measure of DOAC activity. There were close correlations between the PT ratio and drug concentrations measured at the hospital laboratory. The detection level varies between DOACs and may limit its use in some situations. 

Paper IV evaluated the MRX PT DOAC, an assay based on the PT ratio principle. It was found to be able to detect potentially interfering DOAC levels in plasma samples. Confirmatory testing is recommended, as is sensitivity improvement for the detection of specific interferences.   

Abstract [sv]

För nästan exakt 100 år sedan dog boskap i Nordamerika av stora blödningar. Det skulle visa sig att det berodde på att de utfodrats med mögligt hö innehållande gul och vit sötväppling, Melilotus officinalis och Melilotus albus. Den giftiga substans som bildas hindrar blodet från att koagulera. Forskare lyckades identifiera och renframställa substansen, och en vidareutveckling av den gav upphov till warfarin, ett “blodförtunnande” läkemedel (antikoagulantia) i tablettform. Warfarin används än idag, även om nya antikoagulantialäkemedel används allt oftare. För vissa patienter är warfarin ännu det bästa läkemedlet. Warfarinbehandlade patienter kontrolleras regelbundet med analys PK-prov på laboratorium för att behandlingen ska vara säker, och med de nya läkemedlen kommer nya analysutmaningar. Målsättningen med den här avhandlingen har varit att undersöka olika sätt som laboratoriemetoder kan bidra till att förbättra antikoagulantiabehandling.

I delarbete I har vi sett att det finns en koppling mellan vissa genetiska varianter och ett lägre behov av warfarin, och likaså en mer svårinställd behandling.

I delarbete II undersökte vi kvaliteten på warfarinbehandlingen i primärvård jämfört med specialiserade antikoagulantia(AK-)mottagningar genom jämförelse av hur PK-proven under en viss vecka förhöll sig till önskade värden. Båda vårdformerna visade god kvalitet på warfarinbehandlingen, minst lika bra i primärvården som på AK-mottagningarna. Sedan studien gjordes har nästan all warfarinbehandling centraliserats till AK-mottagningar.

I delarbete III modifierade vi en analysmetod som vanligen används för analys av PK-prov, med sikte på att också kunna använda den för analys av effekt av de nya antikoagulantialäkemedlen. Vi såg en god överensstämmelse mellan den modifierade metodens resultat och ordinarie analys.

I delarbete IV utvärderade vi MRX PT DOAC, en analysmetod som bygger på den princip som beskrivs i delarbete III. Vi använde MRX PT DOAC för att upptäcka prover med läkemedel som kan störa andra analyser. Vi såg goda resultat men också förbättringspotential.  

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2023. p. 76
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1875
Keywords
Anticoagulants, Warfarin, DOAC, PT-INR, VKORC1
National Category
Basic Medicine
Identifiers
urn:nbn:se:liu:diva-198901 (URN)10.3384/9789180753470 (DOI)9789180753463 (ISBN)9789180753470 (ISBN)
Public defence
2023-11-28, Hugo Theorell, Building 440, Campus US, Linköping, 09:00 (Swedish)
Opponent
Supervisors
Available from: 2023-10-31 Created: 2023-10-31 Last updated: 2023-11-02Bibliographically approved

Open Access in DiVA

fulltext(557 kB)605 downloads
File information
File name FULLTEXT01.pdfFile size 557 kBChecksum SHA-512
e411100d1364800589a553630365f2d914cd1dcadcaa7cdbaa58b518e692465b781a9bdf35c53957f9063fc6d2db990ef749e164c1ddda7746925fbc11034d94
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records

Arbring, KerstinUppugunduri, SrinivasLindahl, Tomas

Search in DiVA

By author/editor
Arbring, KerstinUppugunduri, SrinivasLindahl, Tomas
By organisation
Internal MedicineFaculty of Health SciencesDepartment of Acute Internal MedicineClinical ChemistryDepartment of Clinical Chemistry
In the same journal
BMC Health Services Research
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 605 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 714 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf