Con - SMBG Should be the Standard of Care in All Patients with Type 2 Diabetes

Transcription

1 JUNE 9 13, 2006 WASHINGTON, DC Con - SMBG Should be the Standard of Care in All Patients with Type 2 Diabetes Antonio Nicolucci, MD Department of Clinical Pharmacology and Epidemiology Consorzio Mario Negri Sud S. Maria Imbaro (CH) Italy

2 Current guidelines are unanimous in recognizing the need for tight metabolic control in patients with diabetes and in recommending SMBG for most forms of diabetes. SMBG is an essential complement for insulin-treated patients, for both safety reasons and enhancement of effectiveness of insulin through dose adjustments. However, the guidelines are less specific about its use in T2DM patients not treated with insulin. SMBG in patients with T2DM who are not using insulin: What is the evidence?

3 Study SMBG CTRL WMD 95% CI Davidson [-0.98, 0.58] Fontbonne [-0.69, 0.97] Guerci [-0.63, -0.71] Muchmore [-2.07, 0.69] Schwedes [-0.79, -0.13] Total (95% CI) [-0.56, -0.21] Favours SMBG Favours Control

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5 Empirical Evidence of Bias KF Schultz, I Chalmers, RJ Hayes, DG Altman JAMA 1995; 273: Evaluation of 33 meta-analyses involving 250 RCTs Main findings Odds ratios were exaggerated by 41% for trials that used inadequate allocation concealment, and by 30% for unclearly concealed trials.

6 Additional problems Cointervention (structured counseling program only for SMBG group) Baseline HbA1c levels (the benefits seem apparent only in patients with very poor metabolic control) Generalizability (small studies; very high dropout rate (>40%) in the largest trial; poor compliance) Duration of benefit (all the studies have a short duration, usually 6 months)

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8 ,4,2 0,0 -,2 -,4 -,6 -,8 7 HbA1C RCTs Observational studies WMD

9 Predictive Margins, Absolute Percentage Change, and 95% CIs according to Strata of Demographic Variables between Baseline Surveys (National Health and Nutrition Examination Survey, , and Behavioral Risk Factors Surveillance System 1995) and Recent Surveys (National Health and Nutrition Examination Survey, , and Behavioral Risk Factors Surveillance System, 2002)

10 Hba1c by treatment in T2DM patients (N= ) Mean±DS Diet Oral agents Insulin Oral Agents + Insulin Diet 6.0 ± 0.9 HOA 6.8 ± 1.4 Insulin 7.5 ± 1.6 HOA+Insulin 7.8 ± 1.7

11 Multilevel linear regression model for longitudinal assessment of HbA1c Time 0.04 <0.01 SMBG 1/day SMBG 1/week SMBG<1/week or never (rc) - - Time*SMBG 1/day Time* SMBG 1/week Time*SMBG<1/week or never (rc) - - Analysis adjusted for: gender, age, living alone, years of school education, household income, BMI, duration of diabetes, TIBI, diabetes treatment, regular access to structure, setting of care, and time-dependent covariates (BMI, diabetes treatment). Franciosi et al. Diabetic Medicine 2005; 22: β p

12 Multilevel linear regression model for longitudinal assessment of HbA1c Increased frequency of SMBG (n 229) Reduced frequency of SMBG (n 143) β p β p Increased SMBG Decreased SMBG Analysis adjusted for: gender, age, living alone, years of school education, household income, BMI, duration of diabetes, TIBI, diabetes treatment, regular access to structure, setting of care, and time-dependent covariates (BMI, diabetes treatment). Franciosi et al. Diabetic Medicine 2005; 22:

13 There is no evidence that SMBG has a beneficial effect on fasting blood glucose, quality of life, well-being, patient satisfaction and number of hypoglycaemic episodes Cochrane Database Syst Rev Apr 18;(2)

14 If the scientific evidence supporting the role of home blood glucose monitoring in type 2 diabetes was subject to the same critical evaluation that is applied to new pharmaceutical agents, then it would perhaps not have been approved for use by patients. BMJ 2004; 329:754-5

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16 HbA1c SMBG cohort HbA1c non-smbg cohort FBG SMBG cohort FBG non-smbg cohort

17 Compliance >80% Compliance 80% p value for log rank test < days Proportion alive (%)

18 Candesartan HR=0.66 ( ) Placebo HR=0.64 ( ) days Compliance >80% Compliance 80% Proportion alive (%)

19 The impact of SMBG on quality of life

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23 SMBG in patients with T2DM who are not using insulin: Which are the possible reasons for the reduced effectiveness? Who will use the test results? The patient? The physician?

24 The patient The patient is supposed..to learn accurate and reliable monitoring skills, proper interpretation of the results, and how to use the results to adjust medical nutrition therapy, exercise, and pharmacologic therapy to achieve specific glycemic goals RM Bergenstal et al. Am J Med 2005; 118 (9A):1S-6S Is the patient taught the self management skills required to lower the measured glucose values? Is he/she able to act on SMBG results? Which test results are more useful (FBG vs. PPG)?

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26 Correlates of SMBG in T2DM patients Gender Age Males (rc) Females <55 years (rc) years ³ 65 years School Education >5 years (rc) 5 years Diabetes Treatment Diet ± Oral Agents (rc) Insulin Insulin+ Oral Agents Frequency of hypogycemic symptoms Never (rc) ³ 1/ month ³ 1/ week Ability to management insulin doses No (rc) Yes Setting of care DOCs (rc) GPs 0, OR= 1.3 ( ) OR= 0.8 ( ) OR= 0.7 ( ) OR= 0.6 ( ) OR= 2.4 ( ) OR= 2.1 ( ) OR= 2.9 ( ) OR= 2.0 ( ) OR= 2.1 ( ) OR= 0.6 ( ) Diabetes Care 24: ,2001

27 FBG is the main contributor to diurnal hyperglycemia in poorly controlled patients (HbA1c >=8.4%), whereas the contribution of PPG excursions are predominant in moderately controlled patients (HbA1c <8.4%) (Monnier, Diabetes Care 2003). Fasting values serve neither to educate, nor to effectively motivate. Furthermore, it is difficult to counter elevated FBG through behavior modification.

28 The physician SMBG provides patients with real time measurement of their blood glucose levels on a day-to-day basis; nevertheless, this information is presented to the physician at 3-6 months intervals. Does the physician efficiently use the hundreds of records in the logbook? Most meters can easily download results into a PC and graphs can be quickly printed, but this data management capability is underutilized

29 In an era of evidence based medicine and great attention to provide highquality, cost-effective healthcare despite budgetary pressures, it is important to weigh the clinical benefits of any intervention against the costs involved

30 The costs of SMBG The Medicare B program spent more than $460 million on SMBG reimbursement in 2002, more than half its Part B budget for the diabetes ICD-9 code Diabetes Care 2005; 28: Some 90m was spent on testing strips in the United Kingdom in 2001, 40% more than was spent on oral hypoglycaemic agents BMJ 2004; 329:754-5

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32 Many people with diabetes, in particular those with Type 2, have not been given adequate education to enable them either to manage their diabetes for themselves, or to use blood glucose meters effectively. Neither, on the whole, have they been encouraged to alter their treatment, which would produce improved control. The costs of blood glucose monitoring are considerable. In order not to waste resources therefore it is important that people with diabetes are able to utilize home monitoring effectively through diabetes education. Without this education to know when and how to test, and what to do with the results, there is little point in home monitoring. Diabetes UK

33 Conclusions The evidence supporting the use of SMBG in the vast majority of T2DM patients not using insulin is weak The modest clinical benefit documented (if present) must be weighed against the patients discomfort and the huge costs involved Given the existing evidence, it seems prudent to recommend SMBG only to those patients who are able to use SMBG results to adjust diet, excercise, or pharmacologic therapy, or when a specific indication is present

34 Conclusions Large scale randomized trials are urgently needed: To evaluate the long-term effect of SMBG beyond education To evaluate the impact of SMBG not only on HbA1c, but also on FBG, hypoglycemic episodes, QoL, satisfaction, and costs To identify the subgroups of patients more likely/less likely to benefit from SMBG To standardize the educational approach needed to enable patients to manage their diabetes

35 A randomized trial with factorial design to test the efficacy of SMBG in T2DM patients not receiving insulin Effect of SMBG a c usual care Intensive Education Effect of intensive education Effect of SMBG + Education SMBG SMBG + Intensive Education b d b+d vs. a+c c+d vs. a+b d vs. b; d vs. c