Research ArticleOriginal ResearchA

Yield of Opportunistic Targeted Screening for Type 2 Diabetes in Primary Care: The Diabscreen Study

Erwin P. Klein Woolthuis, Wim J. C. de Grauw, Willem H. E. M. van Gerwen, Henk J. M. van den Hoogen, Eloy H. van de Lisdonk, Job F. M. Metsemakers and Chris van Weel
The Annals of Family Medicine September 2009, 7 (5) 422-430; DOI: https://doi.org/10.1370/afm.997

Article Figures & Data

Figures

  • Figure 1.
    Figure 1.

    Study population and algorithm of the screening procedure.

    cFPG1=first capillary fasting plasma glucose; cFPG2 = second capillary fasting plasma glucose; vFPG = venous fasting plasma glucose; NFG=normal fasting plasma glucose; IFG = impaired fasting glucose.

    a Conversion factor to SI units: x 0.0555.

Tables

  • Table 1.

    Baseline Characteristics of High-Risk and Low-Risk Patients in Whom a First Capillary Fasting Plasma Glucose Level Was Measured

    CharacteristicHigh-Risk Patients (n=3,335)Low-Risk Patients (n=398)PValue
    BMI=body mass index; cFPG1=first capillary fasting plasma glucose; GDM = gestational diabetes mellitus.
    a Conversion factor to SI units: ×0.0555.
    b Missing=225.
    c Missing=2,342.
    d Missing=2,726.
    Sex (male), No. (%)1,411 (42.3)168 (42.2).97
    Age, mean (SD), years58.2 (8.2)57.5 (7.2).07
    cFPG1
        cFPG1, mean (SD), mg/dLa99.1 (21.6)93.7 (10.8)<.001
        cFPG1 110–126 mg/dL, No. (%)394 (11.8)16 (4.0)<.001
        cFPG1 ≥126 mg/dL, No. (%)172 (5.2)6 (1.5)<.001
    BMIb
        BMI, mean (SD), kg/m228.0 (4.5)23.5 (2.2)<.001
        BMI >27 kg/m2, No. (%)1,786 (57.4)0–
    Risk factors
        Hypertension, No. (%)814 (24.4)0–
        Cardiovascular disease, No. (%)499 (15.0)0–
        Lipid metabolism disorders,c No. (%)319 (32.1)0–
        Family history of diabetes, No. (%)1,288 (38.6)0–
        History of GDM,d No. (%)17 (2.8)0–
  • Table 2.

    Characteristics of High-Risk Patients Eligible For Venous FPG Measurement, Comparing Patients With and Without a Venous Sample

    CharacteristicPatients With Venous SamplePatients Without Venous SamplePValue
    BMI = body mass index; FPG = fasting plasma glucose; cFPG1 = first capillary fasting plasma glucose; cFPG2 = second capillary fasting plasma glucose; GDM = gestational diabetes mellitus.
    a Conversion factor to SI units: ×0.0555.
    b Missing = 94 with venous sample; 30 without venous sample.
    c Missing = 100 with venous sample; 26 without venous sample.
    Sex (male), No. (%)57 (45.6)23 (52.3).45
    Age, mean (SD), years58.8 (8.0)58.5 (8.1).87
    cFPG measurements
        cFPG1, mean (SD), mg/dLa156.8 (55.9)151.4 (50.5).59
        cFPG2, mean (SD), mg/dL149.5 (41.4)140.5 (37.8).23
        cFPG1 110–126 mg/dL and cFPG2 ≥126 mg/dL, No. (%)28 (22.4)6 (13.6).21
        cFPG1 ≥ 126 mg/dL and cFPG2 110–126 mg/dL, No. (%)22 (17.6)21 (47.8)<.001
        cFPG1 ≥ 126 mg/dL and cFPG2 ≥ 126 mg/dL, No. (%)75 (60.0)17 (38.6).01
    BMI, mean (SD), kg/m230.2 (4.6)31.0 (6.9).39
    Risk factors
        Hypertension, No. (%)49 (39.2)15 (34.1).55
        Cardiovascular disease, No. (%)22 (17.6)5 (11.4).33
        Lipid metabolism disorders,b No. (%)12 (38.7)3 (21.4).41
        Family history of diabetes, No. (%)58 (46.4)17 (38.6).37
        History of GDM,c No. (%)00–
  • Table 3.

    Characteristics of High-Risk and Low-Risk Patients in Venous FPG Subgroups

    High-Risk Patients IFGLow-Risk Patients
    CharacteristicDiabetes (n=101)(n=20)NFG (n=4)Diabetes (n=2)IFG (n=1)NFG (n=0)
    BMI=body mass index; cFPG1=first capillary fasting plasma glucose; cFPG2 = second capillary fasting plasma glucose; FPG = fasting plasma glucose; vFPG = venous fasting plasma glucose; GDM = gestational diabetes mellitus; IFG = impaired fasting glucose; NFG = normal fasting glucose.
    Note: Statistical analysis of the low-risk group was not possible because of the small numbers.
    a Conversion factor to SI units: ×0.0555.
    b P <.05 in high-risk group.
    c P <.01 in high-risk group.
    d P <.001 in high-risk group.
    e Missing in high-risk group = 8 with diabetes; 1 with IFG; 0 with NFG.
    f Missing in high-risk group = 75 with diabetes; 11 with IFG; 3 with NFG.
    g Missing in high-risk group = 80 with diabetes; 17 with IFG; 3 with NFG.
    Sex (male), No. (%)49 (48.5)6 (30.0)2 (50.0)1 (50.0)00
    Age, mean (SD), years59.4 (8.1)56.0 (7.8)55.8 (2.6)67.5 (6.4)55.00
    Plasma glucose levela
        cFPG1, mean (SD), mg/dL162.2 (59.5)129.7 (12.6)126.0 (7.2)b127.9 (1.8)127.90
        cFPG2, mean (SD), mg/dL155.0 (43.2)124.3 (14.4)117.1 (7.2)c135.1 (3.6)129.70
        vFPG, mean (SD), mg/dL164.0 (41.4)120.7 (3.6)104.5 (5.4)d133.3 (7.2)110.00
    BMIe
        BMI, mean (SD), kg/m229.9 (3.9)32.2 (6.9)28.2 (4.8)25.3 (1.5)25.30
        BMI >27 kg/m2, No. (%)73 (78.5)17 (89.5)2 (50.0)000
    Risk factors
        Hypertension, No. (%)41 (40.6)7 (35.0)1 (25.0)000
        Cardiovascular disease, No. (%)17 (16.8)5 (25.0)0000
        Lipid metabolism disorders,f No. (%)6 (23.1)6 (66.7)0b000
        Family history of diabetes, No. (%)43 (42.6)13 (65.0)2 (50.0)000
        History of GDM,g No. (%)000000
  • Table 4.

    Univariate Analysis of the Association Between Diabetes Risk Factors and the Odds of Undiagnosed Type 2 Diabetes

    Undiagnosed Diabetes
    Risk FactorYes, No. (%) (n=95)No, No. (%) (n=3,379)Odds Ratio (95% CI)PValue
    BMI=body mass index; CI=confidence interval.
    Note: Missing=259.
    Sex (male)46 (48.4)1,431 (42.3)1.3 (0.9–1.9).24
    Age >60 years45 (47.4)1,406 (41.6)1.3 (0.8–1.9).26
    Hypertension37 (38.9)691 (20.4)2.5 (1.6–3.8)<.001
    Cardiovascular disease16 (16.8)429 (12.7)1.4 (0.8–2.4).23
    Obesity (BMI >27 kg/m2)73 (76.8)1,713 (50.7)3.2 (2.0–5.2)<.001
    Family history of diabetes41 (43.2)1,212 (35.9)1.4 (0.9–2.1).15
  • Table 5.

    Multivariate Analysis of the Association Between Diabetes Risk Factors and the Odds of Undiagnosed Type 2 Diabetes and Diagnostic Performance

    ModelOdds Ratio (95% CI)PValueUndiagnosed Diabetes, No. (%)AUC (95% CI)a
    AUC = area under the receiver operating characteristic curve; BMI = body mass index; CI = confidence interval.
    Note: Only risk factors with P =.15 in Table 4 were included.
    a An AUC of 0.50 means that the model does not predict the outcome better (more accurately) or worse (less accurately) than random guess; an AUC greater than 0.50 means that the prediction is better than random, and an AUC less than 0.50 means that the prediction is worse than random.
    Model 112 (12.6)0.54 (0.48–0.61)
        Obesity (BMI >27 kg/m2)3.1 (1.9–5.0)<.001––
        Hypertension2.3 (1.5–3.5)<.001––
        Family history of diabetes1.4 (1.0–2.2).09––
    Model 230 (31.6)0.60 (0.54–0.66)
        Obesity3.0 (1.9–4.9)<.001––
        Hypertension2.3 (1.5–3.5)<.001––
    Model 373 (76.8)0.63 (0.58–0.68)
        Obesity3.2 (2.0–5.2)<.001––

Additional Files

  • The Article in Brief

    Yield of Opportunistic Targeted Screening for Type 2 Diabetes in Primary Care: The Diabscreen Study

    Erwin P. Klein Woolthuis , and colleagues

    Background The American Diabetes Association recommends that high-risk adults be tested for diabetes. This study assessed the results of opportunistic targeted screening for type 2 diabetes in the primary care setting.

    What This Study Found The yield of an opportunistic targeted screening program was fair: in 1year, undiagnosed type 2 diabetes was identified in 101 high-risk patients (2.7%). The yield of screening in low-risk patients was only 0.4%. Of the American Diabetes Association risk factors, obesity was the strongest predictor of undiagnosed type 2 diabetes.

    Implications

    • Opportunistic screening for type 2 diabetes in primary care could target middle-aged and older adults with obesity.
    • These findings confirm a low yield in screening low-risk individuals for diabetes.

  • Annals Journal Club Selection:

    Sep/Oct 2009

    The Annals of Family Medicine encourages readers to develop the learning community of those seeking to improve health care and health through enhanced primary care. You can participate by conducting a RADICAL journal club, and sharing the results of your discussions in the Annals online discussion for the featured articles. RADICAL is an acronym for: Read, Ask, Discuss, Inquire, Collaborate, Act, and Learn. The word radical also indicates the need to engage diverse participants in thinking critically about important issues affecting primary care, and then acting on those discussions.1

    How it Works

    In each issue, the Annals selects an article or articles and provides discussion tips and questions. We encourage you to take a RADICAL approach to these materials and to post a summary of your conversation in our online discussion. (Open the article online and click on "TRACK Comments: Submit a response.") You can find discussion questions and more information online at: http://www.AnnFamMed.org/AJC/.

    Article for Discussion

    • Klein Woolthuis EP, de Grauw WJC, van Gerwen WHEM. Yield of opportunistic targeted screening for type 2 diabetes in primary care: the Diabscreen study. Ann Fam Med. 2009;7(5):422-430.

    Discussion Tips

    Although screening for diabetes is not recommended for the general population, a great deal of case finding for diabetes occurs through tests ordered for various reasons. The article by Klein Woolthuis and colleagues in this issue can be used to stimulate consideration of whether and how to screen for type 2 diabetes.

    Discussion Questions

    • What question is addressed by the article? How does the question fit with what already is known on this topic?
    • How strong are the study design and data source for answering the question?
    • To what degree can the findings be accounted for by:
    1. How participants were selected?
    2. How outcomes were measured?
    3. Confounding (false attribution of causality because two variables discovered to be associated actually are associated with a 3rd factor)?
    4. Chance?
  • What are the main findings?
  • How comparable is the study population to your practice, and how does this effect the transportability of the findings?
  • How might the high-risk groups be different if the study were done in US family practices?
  • How relevant are the findings to consideration of screening for the general population?
  • How do the recommendations of the US Preventive Services Task Force2 and the American Diabetes Association3 inform your consideration of these findings? How and why do these recommendations differ?
  • How (if at all) does this study change your practice?
  • What important researchable questions remain?

    • References

    1. Stange KC, Miller WL, McLellan LA, et al. Annals journal club: It�s time to get RADICAL. Ann Fam Med. 2006;4(3):196-197. http://annfammed.org/cgi/content/full/4/3/196.
    2. US Preventive Services Task Force. Screening for Type 2 Diabetes Mellitus in Adults. June, 2008. http://www.ahrq.gov/CLINIC/uspstf/uspsdiab.htm. Accessed Jul 25, 2009.
    3. American Diabetes Association (ADA). Standards of medical care in diabetes. II. Testing for pre-diabetes and diabetes in asymptomatic patients. Diabetes Care. 2008;31(Suppl 1):S13-S14. http://care.diabetesjournals.org/content/31/Supplement_1/S12.full. Accessed Jul 25, 2009.
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