Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink

J.T.H. Nielen; B.J.F. van den Bemt; A. Boonen; P.C. Dagnelie; P.J. Emans; N. Veldhorst; A. Lalmohamed; T.P. van Staa; F. de Vries

doi:10.1136/bmjopen-2015-009017

Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink

J.T.H. Nielen^*, B.J.F. van den Bemt, A. Boonen, P.C. Dagnelie, P.J. Emans, N. Veldhorst, A. Lalmohamed, T.P. van Staa, F. de Vries

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Objectives: We aimed to design and test a method to extract information on antithrombotic therapy from anonymised free-text notes in the Clinical Practice Research Datalink (CPRD).

Setting: General practice database representative of the UK.

Participants: All patients undergoing total hip replacement (THR, n=25 898) or total knee replacement (TKR, n=22 231) between January 2008 and October 2012 were included. Antithrombotic drug use related to THR or TKR was identified using anonymised free text and prescription data.

Primary and secondary outcome measures: Internal validity of our newly designed method was determined by calculating positive predictive values (PPVs) of hits for predefined keywords in a random sample of anonymised free-text notes. In order to determine potential detection bias, total joint replacement (TJR) patient characteristics were compared as per their status of exposure to antithrombotics.

Results: PPVs ranging between 97% and 99% for new oral anticoagulants (NOAC) or low-molecular weight heparins (LMWH) exposure related to TJR were obtained with our method. Our search strategy increased detection rates by 57%, yielding a total proportion of 18.5% of all THR and 18.6% of all TKR surgeries. Identified users of NOACs and LMWHs were largely similar with regards to age, sex, lifestyle, disease and drug history compared to patients without identified drug use.

Conclusions: We have developed a useful method to identify additional exposure to NOACs or LMWHs with TJR surgery.

Original language	English
Article number	e009017
Number of pages	8
Journal	BMJ Open
Volume	5
Issue number	11
DOIs	https://doi.org/10.1136/bmjopen-2015-009017
Publication status	Published - 1 Jan 2015

Keywords

TOTAL HIP-REPLACEMENT
KNEE REPLACEMENT
ATRIAL-FIBRILLATION
RIVAROXABAN
DABIGATRAN
APIXABAN
SURGERY
RISK

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Nielen, J. T. H., van den Bemt, B. J. F., Boonen, A., Dagnelie, P. C., Emans, P. J., Veldhorst, N., Lalmohamed, A., van Staa, T. P., & de Vries, F. (2015). Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink. BMJ Open, 5(11), Article e009017. https://doi.org/10.1136/bmjopen-2015-009017

@article{31c2155e004d48fc814f18961e7892e1,

title = "Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink",

abstract = "Objectives: We aimed to design and test a method to extract information on antithrombotic therapy from anonymised free-text notes in the Clinical Practice Research Datalink (CPRD).Setting: General practice database representative of the UK.Participants: All patients undergoing total hip replacement (THR, n=25 898) or total knee replacement (TKR, n=22 231) between January 2008 and October 2012 were included. Antithrombotic drug use related to THR or TKR was identified using anonymised free text and prescription data.Primary and secondary outcome measures: Internal validity of our newly designed method was determined by calculating positive predictive values (PPVs) of hits for predefined keywords in a random sample of anonymised free-text notes. In order to determine potential detection bias, total joint replacement (TJR) patient characteristics were compared as per their status of exposure to antithrombotics.Results: PPVs ranging between 97% and 99% for new oral anticoagulants (NOAC) or low-molecular weight heparins (LMWH) exposure related to TJR were obtained with our method. Our search strategy increased detection rates by 57%, yielding a total proportion of 18.5% of all THR and 18.6% of all TKR surgeries. Identified users of NOACs and LMWHs were largely similar with regards to age, sex, lifestyle, disease and drug history compared to patients without identified drug use.Conclusions: We have developed a useful method to identify additional exposure to NOACs or LMWHs with TJR surgery.",

keywords = "TOTAL HIP-REPLACEMENT, KNEE REPLACEMENT, ATRIAL-FIBRILLATION, RIVAROXABAN, DABIGATRAN, APIXABAN, SURGERY, RISK",

author = "J.T.H. Nielen and {van den Bemt}, B.J.F. and A. Boonen and P.C. Dagnelie and P.J. Emans and N. Veldhorst and A. Lalmohamed and {van Staa}, T.P. and {de Vries}, F.",

year = "2015",

month = jan,

day = "1",

doi = "10.1136/bmjopen-2015-009017",

language = "English",

volume = "5",

journal = "BMJ Open",

issn = "2044-6055",

publisher = "BMJ Publishing Group",

number = "11",

}

Nielen, JTH, van den Bemt, BJF, Boonen, A , Dagnelie, PC , Emans, PJ , Veldhorst, N, Lalmohamed, A, van Staa, TP & de Vries, F 2015, 'Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink', BMJ Open, vol. 5, no. 11, e009017. https://doi.org/10.1136/bmjopen-2015-009017

TY - JOUR

T1 - Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink

AU - Nielen, J.T.H.

AU - van den Bemt, B.J.F.

AU - Boonen, A.

AU - Dagnelie, P.C.

AU - Emans, P.J.

AU - Veldhorst, N.

AU - Lalmohamed, A.

AU - van Staa, T.P.

AU - de Vries, F.

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Objectives: We aimed to design and test a method to extract information on antithrombotic therapy from anonymised free-text notes in the Clinical Practice Research Datalink (CPRD).Setting: General practice database representative of the UK.Participants: All patients undergoing total hip replacement (THR, n=25 898) or total knee replacement (TKR, n=22 231) between January 2008 and October 2012 were included. Antithrombotic drug use related to THR or TKR was identified using anonymised free text and prescription data.Primary and secondary outcome measures: Internal validity of our newly designed method was determined by calculating positive predictive values (PPVs) of hits for predefined keywords in a random sample of anonymised free-text notes. In order to determine potential detection bias, total joint replacement (TJR) patient characteristics were compared as per their status of exposure to antithrombotics.Results: PPVs ranging between 97% and 99% for new oral anticoagulants (NOAC) or low-molecular weight heparins (LMWH) exposure related to TJR were obtained with our method. Our search strategy increased detection rates by 57%, yielding a total proportion of 18.5% of all THR and 18.6% of all TKR surgeries. Identified users of NOACs and LMWHs were largely similar with regards to age, sex, lifestyle, disease and drug history compared to patients without identified drug use.Conclusions: We have developed a useful method to identify additional exposure to NOACs or LMWHs with TJR surgery.

AB - Objectives: We aimed to design and test a method to extract information on antithrombotic therapy from anonymised free-text notes in the Clinical Practice Research Datalink (CPRD).Setting: General practice database representative of the UK.Participants: All patients undergoing total hip replacement (THR, n=25 898) or total knee replacement (TKR, n=22 231) between January 2008 and October 2012 were included. Antithrombotic drug use related to THR or TKR was identified using anonymised free text and prescription data.Primary and secondary outcome measures: Internal validity of our newly designed method was determined by calculating positive predictive values (PPVs) of hits for predefined keywords in a random sample of anonymised free-text notes. In order to determine potential detection bias, total joint replacement (TJR) patient characteristics were compared as per their status of exposure to antithrombotics.Results: PPVs ranging between 97% and 99% for new oral anticoagulants (NOAC) or low-molecular weight heparins (LMWH) exposure related to TJR were obtained with our method. Our search strategy increased detection rates by 57%, yielding a total proportion of 18.5% of all THR and 18.6% of all TKR surgeries. Identified users of NOACs and LMWHs were largely similar with regards to age, sex, lifestyle, disease and drug history compared to patients without identified drug use.Conclusions: We have developed a useful method to identify additional exposure to NOACs or LMWHs with TJR surgery.

KW - TOTAL HIP-REPLACEMENT

KW - KNEE REPLACEMENT

KW - ATRIAL-FIBRILLATION

KW - RIVAROXABAN

KW - DABIGATRAN

KW - APIXABAN

KW - SURGERY

KW - RISK

U2 - 10.1136/bmjopen-2015-009017

DO - 10.1136/bmjopen-2015-009017

M3 - Article

SN - 2044-6055

VL - 5

JO - BMJ Open

JF - BMJ Open

IS - 11

M1 - e009017

ER -

Identification of antithrombotic drugs related to total joint replacement using anonymised free-text notes: a search strategy in the Clinical Practice Research Datalink

Abstract

Keywords

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