Adherence to Canadian Diabetes Association Clinical Practice Guidelines: METHODS

28 Nov
2010

This quality assessment was performed at the Diabetes Education Centre of Lions Gate Hospital. The study was approved by the University of British Columbia Clinical Research Ethics Board.

The primary quality indicator was the 2003 version of the CDA CPGs. However, CPGs may lack explicit guidance for evaluating implementation of various recommendations, such as which targets are most crucial. Therefore, a second quality indicator, the Quality Indicator Set for Diabetes, was also used. This guide for assessing the quality of diabetes care within health care systems was created by the Canadian Consensus for Standardized Evaluation of Quality Improvement Interventions in Type 2 Diabetes and is intended to be used in conjunction with the 2003 CPGs of the CDA. For the purposes of this study, it was used to assist in selecting which CDA recommendations would be reported (Table 1). Specifically, patient results related to CDA recommendations were reported if those recommendations were reiterated in the Quality Indicator Set for Diabetes and the data were available.

Table 1. Summary of Recommendations of the 2003 Clinical Practice Guidelines of the Canadian Diabetes Association




Parameter




Recommendation




Monitoring



Hemoglobin

A
,c



Once every


3


months


Lipid panel


Once at baseline


Urinary albumin to creatinine ratio


Once at baseline, then once yearly


Eye examination



Once at baseline, then once every


2


years




Laboratory targets


Fasting plasma glucose



4-7


mmol/L within


2-3


months*



Hemoglobin

A
,c



< 7.0%


within


6-12


monthst


Blood pressure



Systolic


< 130


mm Hg, diastolic


< 80


mm Hgt


LDL cholesterol



< 2.5


mmol/Lt


Ratio total cholesterol to HDL
cholesterol


< 4Ф




Medications


Antihyperglycemic agent



If fasting plasma glucose


> 7


mmol/L within


2-3


months*


Antihypertensive agent



If blood pressure


> 130/80


mm Hg§


Statin



If LDL cholesterol


> 2.5


mmol/L§


Acetylsalicylic acid


If atherosclerotic risk factors
present§II



HDL


=


high-density lipoprotein, LDL


=


low-density liprotein.



*Reported as fasting plasma glucose level within


3


months.



tReported as hemoglobin

A
,c


< 7%


within


12


months.


tBased on most recent measurement
available during study period.


§Reported at any time during study
period.



IIDefined as Framingham 10-year risk score


> 10%.

This study involved a review of health records. Consecutive patients were identified and included if they had type 2 diabetes, were 19-69 years old, and had attended a session 1 class at the Diabetes Education Centre between January 1 and December 31, 2004. Potential participants were excluded if they had died during the study period. Patient data were collected up to and including February 14, 2006.

Three sets of outcomes were determined: (1) the percentage of patients for whom CDA-recommended monitoring frequency was achieved for hemoglobin A1C, lipid profile, urinary albumin to creatinine ratio, and eye examination; (2) the percentage of patients for whom CDA-recommended laboratory targets were achieved for fasting plasma glucose, hemoglobin A1C, blood pressure, low-density-lipoprotein (LDL) cholesterol, and the ratio of total to high-density-lipoprotein (HDL) cholesterol; and (3) the percentage of eligible patients who received CDA-recommended medications, specifically antihyper- glycemic agents, antihypertensive agents, statins, and acetylsalicylic acid. Within each patient’s health record, the date of diagnosis of type 2 diabetes was collected from the physician’s referral form. Laboratory results were available for use in this study if they had been gathered and recorded by staff of the Diabetes Education Centre. If more than one set of laboratory results was available for any given time frame, the most recent set was used. Smoking, alcohol use, exercise, medications, eye examinations, and comorbidities were self-reported by the patient and documented in the health record. At each visit to the Diabetes Education Centre, staff also recorded the patient’s body mass index and blood pressure, as well as information about any issues that had been addressed during the visit.

Table 2. Definition of Time Frames




Recommended Time Frame




Defined Time Frame, Including Grace Period


Baseline



3


months before to


< 1


month after session


1*


3 months



1


month to


< 4.5


months after session


1


6 months



4.5


months to


< 9


months after session


1



12


months



9


months to


< 15


months after session


1



18


months



15


months to


< 21


months after session


1


24 months


21 months to < 27 months after session
1



*Session


1


refers to the first day the patient attended the Diabetes Education
Centre.

All dates were calculated from the patient’s first visit to the Diabetes Education Centre. If a CPG recommen­dation stated that a target was to be achieved within a specific span of time (e.g., hemoglobin AK < 7.0% within 6-12 months), we determined if the target had been achieved at the shortest time point (6 months in the example) or at the longest time point (12 months in the example), answered affirmatively if it had been achieved at either time point, and reported it as having been achieved within the longest time point (“within 12 months” in the example). For each recommended time frame, a grace period was defined to allow for the reality that patient visits cannot always be scheduled on the exact follow-up date and to incorporate clinical judgement (Table 2).

A patient was deemed to meet the criteria for “atherosclerotic risk factors” if the calculated Framingham 10-year risk score for coronary heart disease was 10% or more. Metabolic syndrome was defined as 3 or more of the following risk determinants: fasting plasma glucose > 6.1 mmol/L, blood pressure > 130/85 mm Hg, triglycerides > 1.7 mmol/L, HDL cholesterol < 1.0 mmol/L for men or < 1.3 mmol/L for women, and waist circumference > 102 cm for men or > 88 cm for women.

Data were tabulated using Microsoft Excel 2000. The mean and standard deviation were reported for normally distributed data; the median and interquartile range were reported for skewed data.

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