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Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores

Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores
Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores
Background:

Suspected urinary tract infection (UTI) is one of the most common presentations in primary care. Systematic reviews have not documented any adequately powered studies in primary care that assess independent predictors of laboratory diagnosis.

Aim:

To estimate independent clinical and dipstick predictors of infection and to develop clinical decision rules.

Design of study:

Validation study of clinical and dipstick findings compared with laboratory testing.

Setting:

General practices in the south of England.

Method:

Laboratory diagnosis of 427 women with suspected UTI was assessed using European urinalysis guidelines. Independent clinical and dipstick predictors of diagnosis were estimated.

Results:

UTI was confirmed in 62.5% of women with suspected UTI. Only nitrite, leucocyte esterase (+ or greater), and blood (haemolysed trace or greater) independently predicted diagnosis (adjusted odds ratios 6.36, 4.52, 2.23 respectively). A dipstick decision rule, based on having nitrite, or both leucocytes and blood, was moderately sensitive (77%) and specific (70%); positive predictive value (PPV) was 81% and negative predictive value (NPV) was 65%. Predictive values were improved by varying the cut-off point: NPV was 73% for all three dipstick results being negative, and PPV was 92% for having nitrite and either blood or leucocyte esterase. A clinical decision rule, based on having two of the following: urine cloudiness, offensive smell, and dysuria and/or nocturia of moderate severity, was less sensitive (65%) (specificity 69%; PPV 77%, NPV 54%). NPV was 71% for none of the four clinical features, and the PPV was 84% for three or more features.

Conclusions:

Simple decision rules could improve targeting of investigation and treatment. Strategies to use such rules need to take into account limited negative predictive value, which is lower than expected from previous research.
clinical scoring algorithms, diagnosis, dipsticks, urinary tract infection
0960-1643
606-612
Little, P.
1bf2d1f7-200c-47a5-ab16-fe5a8756a777
Turner, S.
42f19397-8e9f-435d-a348-2cc1639b5eb4
Rumsby, K.
2002ee8a-32ac-4119-869d-ed35164c3b51
Warner, G.
a7c8d450-67a4-46c9-ad1e-4a17d6816590
Moore, M.
1be81dad-7120-45f0-bbed-f3b0cc0cfe99
Lowes, J.A.
eff6751b-62b6-4755-a92e-b1c6e03db3b6
Smith, H.
cc42a332-71ec-436f-8207-9151275a92d8
Hawke, C.
a10de6c7-ee96-4ea1-aa75-571dd87d1e63
Mullee, M.
fd3f91c3-5e95-4f56-8d73-260824eeb362
Little, P.
1bf2d1f7-200c-47a5-ab16-fe5a8756a777
Turner, S.
42f19397-8e9f-435d-a348-2cc1639b5eb4
Rumsby, K.
2002ee8a-32ac-4119-869d-ed35164c3b51
Warner, G.
a7c8d450-67a4-46c9-ad1e-4a17d6816590
Moore, M.
1be81dad-7120-45f0-bbed-f3b0cc0cfe99
Lowes, J.A.
eff6751b-62b6-4755-a92e-b1c6e03db3b6
Smith, H.
cc42a332-71ec-436f-8207-9151275a92d8
Hawke, C.
a10de6c7-ee96-4ea1-aa75-571dd87d1e63
Mullee, M.
fd3f91c3-5e95-4f56-8d73-260824eeb362

Little, P., Turner, S., Rumsby, K., Warner, G., Moore, M., Lowes, J.A., Smith, H., Hawke, C. and Mullee, M. (2006) Developing clinical rules to predict urinary tract infection in primary care settings: sensitivity and specificity of near patient tests (dipsticks) and clinical scores. British Journal of General Practice, 56 (529), 606-612. (PMID:16882379)

Record type: Article

Abstract

Background:

Suspected urinary tract infection (UTI) is one of the most common presentations in primary care. Systematic reviews have not documented any adequately powered studies in primary care that assess independent predictors of laboratory diagnosis.

Aim:

To estimate independent clinical and dipstick predictors of infection and to develop clinical decision rules.

Design of study:

Validation study of clinical and dipstick findings compared with laboratory testing.

Setting:

General practices in the south of England.

Method:

Laboratory diagnosis of 427 women with suspected UTI was assessed using European urinalysis guidelines. Independent clinical and dipstick predictors of diagnosis were estimated.

Results:

UTI was confirmed in 62.5% of women with suspected UTI. Only nitrite, leucocyte esterase (+ or greater), and blood (haemolysed trace or greater) independently predicted diagnosis (adjusted odds ratios 6.36, 4.52, 2.23 respectively). A dipstick decision rule, based on having nitrite, or both leucocytes and blood, was moderately sensitive (77%) and specific (70%); positive predictive value (PPV) was 81% and negative predictive value (NPV) was 65%. Predictive values were improved by varying the cut-off point: NPV was 73% for all three dipstick results being negative, and PPV was 92% for having nitrite and either blood or leucocyte esterase. A clinical decision rule, based on having two of the following: urine cloudiness, offensive smell, and dysuria and/or nocturia of moderate severity, was less sensitive (65%) (specificity 69%; PPV 77%, NPV 54%). NPV was 71% for none of the four clinical features, and the PPV was 84% for three or more features.

Conclusions:

Simple decision rules could improve targeting of investigation and treatment. Strategies to use such rules need to take into account limited negative predictive value, which is lower than expected from previous research.

Full text not available from this repository.

More information

Published date: 1 August 2006
Keywords: clinical scoring algorithms, diagnosis, dipsticks, urinary tract infection
Organisations: Primary Care & Population Sciences

Identifiers

Local EPrints ID: 358074
URI: http://eprints.soton.ac.uk/id/eprint/358074
ISSN: 0960-1643
PURE UUID: 7134f594-51c6-417b-a4f7-1e660078c16f
ORCID for K. Rumsby: ORCID iD orcid.org/0000-0002-8573-3718
ORCID for M. Moore: ORCID iD orcid.org/0000-0002-5127-4509

Catalogue record

Date deposited: 01 Oct 2013 11:07
Last modified: 17 Dec 2019 01:56

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Contributors

Author: P. Little
Author: S. Turner
Author: K. Rumsby ORCID iD
Author: G. Warner
Author: M. Moore ORCID iD
Author: J.A. Lowes
Author: H. Smith
Author: C. Hawke
Author: M. Mullee

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