You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.
 

CME

Rule Developed to Diagnose Gout Using Clinical Variables

  • Authors: News Author: Emma Hitt, PhD
    CME Author: Laurie Barclay, MD
  • CME Released: 7/21/2010
  • THIS ACTIVITY HAS EXPIRED
  • Valid for credit through: 7/21/2011
Start Activity


Target Audience and Goal Statement

This article is intended for primary care clinicians and specialists caring for patients thought to have acute gouty arthritis.

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  1. Describe the validity of the diagnosis of acute gouty arthritis by family physicians, based on a Dutch study sample.
  2. Describe a diagnostic rule to assist family practitioners in the diagnosis of acute gouty arthritis, based on a Dutch study sample.


Disclosures

As an organization accredited by the ACCME, Medscape, LLC requires everyone who is in a position to control the content of an education activity to disclose all relevant financial relationships with any commercial interest. The ACCME defines "relevant financial relationships" as financial relationships in any amount, occurring within the past 12 months, including financial relationships of a spouse or life partner, that could create a conflict of interest.

Medscape, LLC encourages Authors to identify investigational products or off-label uses of products regulated by the US Food and Drug Administration, at first mention and where appropriate in the content.


Author(s)

  • Emma Hitt, PhD

    Emma Hitt is a freelance editor and writer for Medscape.

    Disclosures

    Disclosure: Emma Hitt, PhD, has disclosed no relevant financial relationships.
    Dr. Hitt does not intend to discuss off-label uses of drugs, mechanical devices, biologics, or diagnostics not approved by the FDA for use in the United States.
    Dr. Hitt does not intend to discuss investigational drugs, mechanical devices, biologics, or diagnostics not approved by the FDA for use in the United States.

Editor(s)

  • Brande Nicole Martin

    CME Clinical Editor, Medscape, LLC

    Disclosures

    Disclosure: Brande Nicole Martin has disclosed no relevant financial relationships.

CME Author(s)

  • Laurie Barclay, MD

    Freelance writer and reviewer, Medscape, LLC

    Disclosures

    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.

CME Reviewer(s)

  • Sarah Fleischman

    CME Program Manager, Medscape, LLC

    Disclosures

    Disclosure: Sarah Fleischman has disclosed no relevant financial relationships.


Accreditation Statements

    For Physicians

  • Medscape, LLC is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

    Medscape, LLC designates this educational activity for a maximum of 0.25 AMA PRA Category 1 Credit(s)™ . Physicians should only claim credit commensurate with the extent of their participation in the activity. Medscape News CME has been reviewed and is acceptable for up to 300 Prescribed credits by the American Academy of Family Physicians. AAFP accreditation begins September 1, 2009. Term of approval is for 1 year from this date. Each issue is approved for .25 Prescribed credits. Credit may be claimed for 1 year from the date of this issue.

    Note: Total credit is subject to change based on topic selection and article length.

    Medscape, LLC staff have disclosed that they have no relevant financial relationships.

    AAFP Accreditation Questions

    Contact This Provider

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]


Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page.

Follow these steps to earn CME/CE credit*:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. MedscapeCME encourages you to complete the Activity Evaluation to provide feedback for future programming.

You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 6 years; at any point within this time period you can print out the tally as well as the certificates by accessing "Edit Your Profile" at the top of your Medscape homepage.

*The credit that you receive is based on your user profile.

CME

Rule Developed to Diagnose Gout Using Clinical Variables

Authors: News Author: Emma Hitt, PhD CME Author: Laurie Barclay, MDFaculty and Disclosures
THIS ACTIVITY HAS EXPIRED

CME Released: 7/21/2010

Valid for credit through: 7/21/2011

processing....

July 21, 2010 — A diagnostic rule involving 7 clinical variables is useful in helping to determine which patients are at high risk for gout and should undergo further testing with joint fluid aspiration to test for the presence of monosodium urate (MSU) crystals.

Hein J. E. M. Janssens, MD, with the Department of Primary and Community Care, Radboud University Nijmegen Medical Center, in Nijmegen, the Netherlands, and colleagues reported their findings in the July 12, 2010, issue of the Archives of Internal Medicine.

The 7 variables, which the researchers describe as "easily ascertainable in primary care," include male sex, previous patient-reported arthritis attack, onset within 1 day, joint redness, involvement of the first metatarsophalangeal joint (MTP1), hypertension or 1 or more cardiovascular diseases, and serum uric acid level of more than 5.88 mg/dL.

"The presented diagnostic rule helps family physicians to select patients with high vs low probability of gout and to restrict the use of joint fluid aspiration to test for the presence of MSU crystals for patients with remaining uncertainty about the diagnosis," Dr. Janssens and colleagues write.

To validate the diagnostic rule, the investigators recruited 381 patients with monoarthritis. These patients had a mean age of 57.7 years, and 285 (74.8%) were men. MSU crystals were identified in 216 (56.7%) of the patients.

A total of 328 patients (86.1%) had an index test diagnosis of gout. Of these 328 patients, mean age was 58.0 (13.5) years, and 261 (79.6%) were men. MSU crystals was identified in 209 (63.7%) of these patients. On the reference test, the positive and negative predictive values of family physician diagnosis of gout were 0.64 and 0.87, respectively.

When the diagnostic rule was used (score ranging from 0 - 13), a score of 4 or less ruled out gout in almost 100% of patients. According to the researchers, in these patients, a differential diagnosis of rheumatoid arthritis, pseudogout, psoriatic arthritis, and reactive arthritis vs gout should be considered.

Among patients with a score of 8 or higher, gout was confirmed in more than 80%, indicating that gout-specific management options such as "systemic corticosteroid use (instead of nonsteroidal anti-inflammatory drugs), uric acid–lowering therapy if indicated, and evaluation of gout-associated cardiovascular and renal diseases" should be used. A false-positive diagnosis of gout was found in 17% of patients at this score range; by contrast, the family physician false-positive diagnosis rate was 36.3%.

A midrange score (> 4 to < 8) leaves uncertainty about the diagnosis. In these patients, of which approximately 30% had gout, "analysis of synovial fluid from the affected joint for the presence of MSU crystals should be considered if necessary for future management," the researchers suggest.

An online calculator for computing the diagnostic rule is available at the Nijmegen Medical Center Web site.

The study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2010;170:1120-1126. Abstract

Clinical Context

Most patients with gout are diagnosed and treated by primary care physicians. Rheumatology consult occurs in fewer than 10% of patients diagnosed with gout. Missing the diagnosis of gout or making an incorrect diagnosis may result in patients not being treated properly or adequately.

The diagnosis of gout in primary care is based on characteristic clinical signs and symptoms. Typically, synovial fluid aspiration to detect MSU crystals is not performed in primary care, although this is the reference test for diagnosis of gout. It is therefore important to know the validity of acute gouty arthritis diagnosed by family physicians, and it would be useful for them to have a diagnostic rule without the need for synovial fluid analysis.

Study Highlights

  • The goal of the study was to evaluate the validity of the diagnosis of acute gouty arthritis by family physicians, as well as to develop a diagnostic rule to assist family practitioners in this diagnosis.
  • This diagnostic study took place from March 24, 2004, through July 14, 2007, with recruitment of 381 patients with monoarthritis from an open Dutch population.
  • Selection criteria were patients with monoarthritis diagnosed by their family physician as having gout.
  • Of the 381 patients, mean age was 57.7 years, 285 (74.8%) were men, and MSU crystals were identified in 216 (56.7%).
  • 328 patients (86.1%) had an index test (family physician) diagnosis of gout.
  • Of these 328 patients, mean age was 58.0 (13.5) years, 261 (79.6%) were men, and MSU crystals was identified in 209 (63.7%).
  • The reference standard was the presence of MSU crystals in synovial fluid.
  • The investigators estimated validity variables using 2 x 2 tables.
  • Clinical variables used to develop the diagnostic rule (including synovial MSU crystals) were collected within 24 hours.
  • Multivariate logistic regression models to predict the presence of synovial MSU crystals were developed by separately entering statistically significant variables and predefined variables.
  • Receiver operating characteristic curve analysis allowed determination of diagnostic performance of the models.
  • Using the best model, the investigators developed a clinically useful diagnostic rule.
  • For family physician diagnosis of gout, the positive predictive value was 0.64, and the negative predictive value was 0.87.
  • Predefined variables contributing to the best model were male sex, previous patient-reported arthritis attack, onset within 1 day, joint redness, involvement of the MTP1, at least 1 cardiovascular disease such as hypertension, and serum uric acid level of more than 5.88 mg/dL.
  • For this model, the area under the receiver operating characteristic curve was 0.85 (95% confidence interval, 0.81 - 0.90).
  • Transforming the regression coefficients to easy-to-use scores did not affect performance, which was almost equal to that of the statistically optimal model.
  • A score of 4 or less on the diagnostic rule excluded gout in nearly 100% of patients, suggesting the need to consider diagnoses such as rheumatoid arthritis, pseudogout, psoriatic arthritis, and reactive arthritis.
  • The maximal score was 13. Gout was confirmed in more than 80% of patients with a score of 8 or higher.
  • The clinical scores of the final diagnostic rule were as follows:
    • Male sex: 2.0
    • Previous patient-reported arthritis attack: 2.0
    • Onset within 1 day: 0.5
    • Joint redness: 1.0
    • MTP1 involvement: 2.5
    • At least 1 cardiovascular disease: 1.5
    • Serum uric acid level of more than 5.88 mg/dL: 3.5
  • On the basis of these findings, the investigators concluded that the validity of family physician diagnosis of acute gouty arthritis was moderate in this study, and that they had developed an easy-to-use diagnostic rule without joint fluid analysis.
  • Limitations of this study include patients with monoarthritis and clinical variables assessed by an investigator rather than the primary physician, limiting generalizability.
  • Possible selection bias and verification bias are additional limitations.

Clinical Implications

  • The validity of family physician diagnosis of acute gouty arthritis without joint fluid analysis was moderate in a Dutch study sample. The positive predictive value was 0.64, and the negative predictive value was 0.87.
  • An easy-to-use diagnostic rule was developed that improved diagnostic performance without joint fluid analysis. Clinical factors contributing to the diagnostic score were male sex, previous patient-reported arthritis attack, onset within 1 day, joint redness, MTP1 involvement, at least 1 cardiovascular disease such as hypertension, and serum uric acid level of more than 5.88 mg/dL.

CME Test