Drug Use Evaluation (DUE) Bulletin - November 2004
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The Non-Insured Health Benefits (NIHB) Program
provides supplementary health benefits, including prescription
and non-prescription drugs, for registered Indians, and recognized
Inuit and Innu throughout Canada.
Use of Angiotensin-Coverting Enzyme (ACE)
Inhibitors, Angiotensin-Receptor Blockers (ARB) and Antiplatelet
Medications for Diabetes Care in First Nations and Inuit clients
of the NIHB program.
Summary Recommendations
In December 2003, the NIHB Program created a Drug Use Evaluation
Advisory Committee (DUEAC)(For further information on the DUEAC, please see
the November 2004 NIHB Drug Bulletin.) to provide recommendations to the
Program to promote improvement in the health outcomes of First
Nations and Inuit clients through effective use of pharmaceuticals.
The membership of the DUEAC is listed at the end of this bulletin.
This DUE Bulletin reviews the Committee's findings from its drug
use evaluation of diabetes claimants of the NIHB Program and recommends
that:
- Physicians and pharmacists should continue to ensure that
all adults with diabetes are prescribed recommended drug therapies
known to decrease cardiovascular risk such as ACE inhibitors,
particularly in women. Statin therapy should also be prescribed
if required and not contraindicated.
- In order to promote optimal therapy for the prevention or
treatment of cardiovascular disease, physicians and pharmacists
are reminded that acetylsalicylic acid (ASA), including low-dose
ASA, are funded as full benefits under the NIHB Program.
Diabetes is a national problem that has reached epidemic proportions.
Complications from this chronic disease are serious, and include
kidney and heart disease, blindness, and amputations.
Diabetes is a significant health concern among First Nations and
Inuit. Indeed, rates of diabetes among Aboriginal people in Canada
are three to five times higher than those of the general Canadian
population, with aboriginal women being particularly vulnerable.
Inuit rates of diabetes are not as high as those of other Aboriginal
populations; however, there is concern that the rates of type 2
diabetes are increasing among Inuit as well(For more information, visit www.hc-sc.gc.ca/fnihb/cp/adi/index.htm).
The care and treatment of diabetes includes not only glucose management
but also the management of cardiovascular risk, in order to decrease
the risk and incidence of diabetic complications. The current Canadian
Diabetes Association (CDA) 2003 Clinical Practice Guidelines 3
suggest "the first priority in the prevention of diabetes complications
should be reduction of cardiovascular risk by vascular protection
through a comprehensive multifaceted approach." The medical management
to decrease cardiovascular risk should therefore start when Type
(Canadian Diabetes Association Clinical Practice Guidelines.
Can J Diabetes 2003. Available at: www.diabetes.ca) diabetes is diagnosed.
As one of its first actions, the DUEAC recommended that the Program
undertake a drug use evaluation of drug therapy used in cardiovascular
risk reduction for diabetes claimants of the NIHB Program. This
topic meets the predefined criteria for a critical drug issue as
diabetes has a high prevalence in First Nations and Inuit communities,
the drugs used in diabetes management have large variations in
use and these drugs have shown positive and measurable impacts
on health outcomes.
Purpose of this Drug Use Evaluation
Strategies known to decrease cardiovascular risk in patients with
diabetes include drug therapies with antiplatelet agents and ACE
inhibitors as well as statins. The purpose of this drug use evaluation
was therefore to determine the rate of prescribing of ACE inhibitor
and antiplatelet therapy among diabetes claimants of the NIHB Program.
The use of angiotensin receptor blockers (ARBs) was also included
in this analysis because they are recommended in the CDA guidelines
for both renal protection as well as treatment of hypertension
and are often used when ACE inhibitor therapy is not tolerated.
Methods
This was a retrospective analysis of an encrypted data set respecting
patient privacy. Clients of the NIHB Program who had been dispensed
at least two prescriptions from April 2002 until December 2003
for antihyperglycemic therapy comprised the study population. Because
Type 1 diabetes is rare in First Nations, we assumed the vast majority
of clients who were dispensed antihyperglycemic therapy were diagnosed
with Type 2 diabetes.
From this population, the number of clients who were dispensed
at least 1 prescription of an ACE inhibitor, an ARB, or antiplatelet
therapy (ASA or clopidrogel) was determined.
The ACE inhibitors were defined as benazepril, captopril, cilazapril,
enalapril, fosinopril, lisinopril, perindopril, quinapril, ramipril,
trandolapril and their combinations with other antihypertensives.
The ARBs were defined as candesartan, eprosartan, irbesartan, losartan,
telmisartan, valsartan and their combinations with other antihypertensives.
The primary outcome measure was to determine if the utilization
rate for ACE inhibitors and/or ARBs was >75% in patients aged >55
years,and in patients >30 yrs of age if antiplatelet utilization
was >80%. These statistical benchmarks were drawn from the Health
Disparities Collaborative(Measures of Diabetes Population 2003-04, Health Disparities
Collaboratives, US Department of Health and Human Services. www.healthdisparities.net ).
Demographics
For the period of analysis, the NIHB Program had approximately
35,000 individuals who were dispensed at least 2 prescriptions
for antihyperglycemic drug therapy during the specified time period.
The average age of this population was 54.6 ± 14.5 years
and 58% were female. A total of 1589 clients (4.6%) were less than
30 years of age. These data are consistent with published data
on diabetes among First Nations; patients with diabetes are younger
and more likely to be female when compared to the non-aboriginal
population.
Key Findings
- ACE inhibitors and/or ARB therapy was dispensed to 76.7% of
claimants aged >55 years which appears to be similar to recommended
thresholds from the US Diabetes Collaborative Outcome Models.
A total of 70% of clients >55 years were dispensed an ACE
inhibitor; females were more likely to receive an ARB than males.
For the entire cohort, ACE inhibitors or ARBs were dispensed
to 65.4% of diabetes clients of the NIHB Program with the use
of ACE inhibitors at 60% overall.
- Antiplatelet drug therapy was dispensed to approximately 43%
of diabetes claimants of the NIHB Program who were aged >30
years. Females over 55 years of age were less likely to be dispensed
antiplatelet therapy than males over 55 years. This is below
the recommended utilization rate. However, this may be influenced
by the fact that ASA is available without a prescription and
may not always be dispensed as a NIHB benefit.
- The use of recommended drug therapy to decrease the risk of
cardiac disease differed by region of residence. The utilization
rate of an ACE inhibitor and/or an ARB varied from one province
to another (range 54.5% to 79.2%), with the utilization of antiplatelet
therapy showing a much greater variation (range 24.8% to 58.6%).
(see Figures 1 and 2)
Limitations of the Analysis
The clients who were dispensed antihyperglycemic therapy may not
be representative of all First Nations and Inuit patients with
diabetes. Clients who were prescribed only 1 antihyperglycemic
medication during the specified time period were not analyzed,
nor were clients who did not access or were not beneficiaries of
the NIHB Program. In addition, the use of antiplatelet therapy
may be underestimated because of its availability as a nonprescription
drug product.
Conclusions
The utilization of ACE inhibitors in older diabetes patients of
the NIHB Program appears to meet predefined criteria and is in
agreement with, or exceeds utilization of such therapies in the
non-aboriginal populations. However, the lower level of use in
younger patients and females, and the lower uptake of antiplatelet
therapies may signify treatment gaps to be addressed in order to
improve the cardiovascular outcomes among First Nations and Inuit
clients with diabetes of the NIHB Program.
Members of the NIHB DUEAC
Richard MacLachlan (Chair)
Head, Department of Family Medicine
Dalhousie University
Bob Nakagawa (co-Chair)
Director, Pharmacy Services
Fraser Health Authority
Ingrid Sketris
Professor, College of Pharmacy
Dalhousie University
Dawn Frail
Manager, Drug Technology Assessment
Drug Evaluation Alliance of Nova Scotia
Nova Scotia Department of Health
Michael Perley
Assistant Professor of Family Medicine
Dalhousie University
Cornelia Wieman
Consultant/Psychiatrist, Six Nations Mental Health Services
Co-Director, Indigenous Health Research Development Program University
of Toronto
Marlyn Cook
Mohawk Council of Akwasasne
Department of Health
Anne Unsworth
Community Health Services Manager
Prince Albert Grand Council
Rick Volpel
Chief Executive Officer
Bigstone Health Commission
Figure 1: Utilization of Either ACE inhibitors or ARBs by First Nations and Inuit Clients by Province. N=34,478
Figure 2: Utilization of ASA or Clopidogrel by First Nations and Inuit Clients by Province, N=34,478
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