DIABETICMedicine DOI: 10.1111/j.1464-5491.2009.02862.x
Short Report Short report: suboptimal diabetes care in high-risk diabetic patients attending a specialist retina clinic S. A. Al-Ansari*, M. T. S. Tennant†, M. D. J. Greve†, B. J. Hinz† and P. A. Senior* *Division of Endocrinology and Metabolism and †Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada Accepted 18 September 2009
Abstract Individuals with diabetic retinopathy (DR) represent a high-risk group who would benefit from intensive metabolic control and risk factor management. This brief report examines quality of care among diabetic patients attending a tertiary retinal clinic.
Aims
Methods A cross-sectional survey, notes review, and slit-lamp examination was conducted in 139 diabetic patients attending a specialist retinal clinic to assess the quality of comprehensive diabetes care. DR was graded according to the Early Treatment Diabetic Retinopathy Study scale.
The prevalence of non-proliferative DR (NPDR) and proliferative DR (PDR) was 39.6 and 35.2%, respectively. The prevalence of microalbuminuria in patients with no DR, NPDR and PDR was 32, 54.1 and 68.8%, respectively. Glycaemic control was suboptimal (mean HbA1c 8.0 1.8%) and 15.8% were current smokers. Drugs affecting the renin–angiotensin system were used by only 61.9% of patients with both DR and microalbuminuria, and aspirin by only 35.3%.
Results
Conclusions These data suggest that diabetes care in this high-risk population with established microvascular complications was suboptimal. Specialist clinics dealing with diabetic complications may be a setting where quality improvement strategies to reduce morbidity and mortality should be focused.
Diabet. Med. 26, 1296–1300 (2009) Keywords complications, glycemic control, health care delivery, retinopathy Abbreviations ACEI, angiotensin converting enzyme inhibitor; ACR, albumin:creatinine ratio; ARB, angiotensin
receptor blocker; CKD, chronic kidney disease; CSMO, clinically significant macular oedema; CVD, cardiovascular disease; DN, diabetic nephropathy; DR, diabetic retinopathy; eGFR, estimated glomerular filtration rate; NPDR, nonproliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy; RAS, renin–angiotensin system; T1DM, Type 1 diabetes mellitus; T2DM, Type 2 diabetes mellitus
Introduction Multifactorial interventions addressing glycaemia, hypertension and vascular risk factors [smoking, use of aspirin and renin– angiotensin system (RAS) blockade] in diabetic patients with microalbuminuria have reduced micro- and macrovascular complications, and mortality by > 50% [1,2]. Delivery of highquality care in clinical practice is not always easy. Poor glycaemic control [3–6], and hypertension [7,8] are important risk factors for diabetic retinopathy (DR) and for diabetic nephropathy (DN) and cardiovascular disease (CVD). Correspondence to: Dr Peter A. Senior, #2000, 8215 112 Street, Edmonton, AB T6G 2C8, Canada. E-mail:
[email protected]
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Thus individuals with DR are not only at risk for visual loss, but also for DN and CVD. We sought to describe the prevalence of DR and DN, and examine glycaemic control and the use of RAS blockade, aspirin and smoking as proxies for quality of care in individuals attending a tertiary care retinal clinic.
Subjects and methods This cross-sectional survey was conducted in 139 diabetic subjects attending a specialist retinal clinic in Edmonton (Alberta, Canada) and was approved by the Health Research Ethics Board. Subjects attending the clinic could be referred by specialists or primary care physicians and included both subjects
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referred for DR screening as well as those referred for assessment and management of established DR. A questionnaire (Appendix) was administered to subjects that identified demographics, diabetes duration, history of hypertension or microalbuminuria, therapy with aspirin, angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blockers (ARB), and diabetes knowledge was assessed from awareness of HbA1c as a test to assess glycaemic control. Drug utilization was confirmed by review of the patient’s medication list and the ophthalmologists’ medical records. Retinopathy in the worst eye was graded using the Early Treatment Diabetic Retinopathy Study scale [9] by an ophthalmologist specializing in retinal diseases and classified as: no DR; mild, moderate or severe non-proliferative DR (NPDR); early or high-risk proliferative DR; and neovascularization of the iris. The presence or absence of clinically significant macular oedema (CSMO) was documented. Laboratory data to assess metabolic control and renal function were obtained by review of the regional electronic laboratory database, which is a central repository for all laboratory results irrespective of which physician ⁄ department ordered the test. Estimated glomerular filtration rate (eGFR) was calculated using the abbreviated Modification of Diet in Renal Disease equation [10]. Inadequate glycaemic control was defined as HbA1c > 7.0% and microalbuminuria as albumin:creatinine ratio (ACR) > 2.65 mg ⁄ mmol. Data are presented as mean SD or median (range). Statistical analysis was performed using spss version 16 for Windows (SPSS Inc., Chicago, IL, USA). Group means were compared using Student’s t-test or anova (using Bonferroni’s correction for multiple testing in post hoc comparisons); and medians compared using Mann–Whitney’s U-test. Proportions were compared using vv2 or Fisher’s exact test. Statistical significance was set at 5%.
Results The clinical and biochemical characteristics are presented in Table 1. Most (78%) had Type 2 diabetes (T2DM). T2DM subjects were older but had shorter diabetes duration. Fifty percent of T2DM subjects were treated with oral glucoselowering agents and 42% were treated with insulin oral glucose-lowering agents. Seventy-five percent of subjects had DR [40% NPDR, 35% proliferative diabetic retinopathy (PDR)]; 63.3% had previously received laser photocoagulation; and 18% of subjects had CSMO. Subjects with PDR or NPDR were younger and had had longer diabetes duration than subjects with no DR. Glycaemic control was worse and ACR higher in subjects with PDR compared with no DR, but was not different in comparison with subjects with NPDR. eGFR did not differ between the groups. Among new referrals (n = 30) there was a positive correlation between retinopathy grade and higher HbA1c values (r = 0.546, P = 0.009).
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Diabetic nephropathy
Only 20.9% of subjects reported a history of nephropathy, but ACR was elevated in 53.2% and stage 3–5 chronic kidney disease (CKD) present in 48.1% (Table 1). Although the prevalence of micro- or macroalbuminuria was higher in subjects with DR (Table 1), the proportion reporting a history of nephropathy was similar in all three groups. This is in contrast to a history of neuropathy, which was reported more frequently in subjects with PDR.
Glycaemic control and diabetes care
Data regarding glycaemic control and diabetes care are also presented in Table 1. Only 34% of subjects had adequate glycaemic control (HbA1c < 7.0%). Mean HbA1c was 8.0 1.8% and was higher in Type 1 diabetes (T1DM) subjects than in T2DM (Table 1). HbA1c was highest, and the proportion with adequate glycaemic control was lowest, in subjects with PDR. The prevalence of reported hypertension was 74.1% and was more commonly reported by subjects with T2DM. Use of aspirin was reported by 35.3% and ACEI or ARB by 58.3%, with no difference between T1DM and T2DM subjects, nor between those with different degrees of DR. Among subjects with both microalbuminuria and DR, use of ACEI or ARB was reported by only 61.9%. Amongst microalbuminuric subjects reporting a history of hypertension, use of ACEI or ARB was reported by 50% of subjects with no DR, 69% of subjects with NPDR, and 59% of those with PDR. There wasnodifferenceinage,diabetesduration,HbA1c,eGFR,orACR between subjects who did or did not report use of ACEI or ARB. Usual diabetes care was provided by general practitioners (66.9%), endocrinologists (24.5%), internists (5.0%) or other physicians (3.6%). T1DM subjects were twice as likely to be followed by an endocrinologist compared with T2DM subjects (41.9% vs. 19.4%, P < 0.02). Although HbA1c had been monitored more recently (5 6 vs. 12 13 months, P = 0.002) and more frequently (2.6 2.2 vs. 1.1 1.2 times in the preceding year, P < 0.001) in subjects followed by endocrinologists, there was no difference in HbA1c levels, smoking status, aspirin use, or use of ACEI or ARB (data not shown). Just over half (54%) of subjects knew that HbA1c is a blood test to assess glycaemic control and those who did were younger (59 16 vs. 68 14 years, P = 0.001) and had HbA1c measured more frequently (1.9 2 vs. 1.3 1.2 times per year, P = 0.05), although glycaemic control was not different (HbA1c 8.1 2.0 vs. 7.8 1.6%, P = 0.35). The interval since last HbA1c measurement did not differ between subjects with no DR, NPDR or PDR [P (anova) = 0.14].
Discussion This cross-sectional survey of diabetic subjects attending a tertiary care retinal specialist clinic confirms that these are indeed
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1
1298 46.3 16.0 — 27.0 11.0 17 ⁄ 13 20 (64.5) 15 (48.4) 6 (19.4) 17 (54.8) 1.7 (0.25–118) 8 ⁄ 19 (42.1) 8 (38.1) 89 (66–977) 71.4 27.9 8.6 1.8 3 (13) 17 (54.8) 11(35.5) 10 ⁄ 5 ⁄ 16
63.6 15.6 31 (22.3) 17.6 11.9 93 ⁄ 46 78 (56.1) 39 (28.1) 29 (20.9) 103 (74.1) 2.9 (0.25–841) 50 ⁄ 94 (53.2) 52 (48.1) 99 (57–977) 62 22.4 8.0 1.8 39 (34.2) 81 (58.3) 49 (35.3) 22 ⁄ 48 ⁄ 69
T1DM (n = 31)
7.8 1.8 36 (39.6) 64 (59.3) 38 (35.2) 12 ⁄ 43 ⁄ 53
58 (53.7) 24 (22.2) 23 (21.3) 86 (79.6) 3.8 (0.39–841) 42 ⁄ 75 (56) 44 (50.6) 99 (57–383) 60 20.5
76 ⁄ 28
68.5 11.5 — 14.9 10.7
T2DM (n = 108)
0.047 0.017 0.66 0.98 0.005
0.29 0.004 0.82 0.005 0.25 0.28 0.35 0.29 0.039
0.11
< 0.001 — < 0.001
P
7.2 1.0 16 (51.6) 22 (61.1) 11 (30.6) 2 ⁄ 15 ⁄ 19
14 (38.9) 4 (11.1) 4 (11.1) 28 (77.8) 2.0 (0.39–62.5) 8 (30.8) 12 (40) 89 (69–167) 66 18.0
27 ⁄ 6
72.9 15.5 3 (8.3) 10.6 11.3
No DR (n = 36)
8.1 2.0 15 (34.1) 35 (64.8) 24 (44.4) 10 ⁄ 19 ⁄ 25
32 (59.3) 14 (25.9) 15 (27.8) 42 (77.8) 3.9 (0.25-292.9) 20 (55.6) 81 (42.9) 102 (57–977) 60 23.7
34 ⁄ 20
63.6 12.4* 12 (22.2) 19.1 11.8*
NPDR (n = 54)
8.5 1.8* 8 (20.5) 24 (49) 14 (28.6) 10 ⁄ 14 ⁄ 25
32 (65.3) 21 (42.9) 10 (20.4) 33 (67.3) 6.5 (0.44–841)* 22 (68.8) 21 (58.3) 105 (63–383) 62 24.5
32 ⁄ 15
56.7 15.7* 16 (32.7) 21.2 10.2*
PDR (n = 49)
N (%) or mean SD or median (range). T1DM, Type 1 diabetes mellitus; T2DM, Type 2 diabetes mellitus; DR, diabetic nephropathy; NPDR, non-proliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy; HTN hypertension; ACR, albumin:creatinine ratio; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; ACEI, angiotensin converting enzyme inhibitor; ARB, angiotensin receptor blocker.
Age (years) Type 1 diabetes (%) Diabetes duration (years) Diabetes follow-up (GP ⁄ specialist) Male gender (%) Reported neuropathy (%) Reported nephropathy (%) Reported HTN (%) Median ACR (mg ⁄ mmol) ACR > 2.65 (%) CKD stage 3–5 (%) Creatinine (lmol ⁄ l) eGFR (ml ⁄ min per 1.73 m2) HbA1c (%) HbA1c £ 7.0% ACEI or ARB use (%) Aspirin use (%) Smoking current ⁄ ex ⁄ never
All subjects (n = 139)
Table 1 Clinical and biochemical characteristics of study participants
0.007 0.024 0.25 0.19 0.34
0.044 0.005 0.16 0.41 03 0.015 0.26 0.23 0.63
0.18
< 0.001 0.029 < 0.001
P (anova)
DIABETICMedicine Quality of diabetes care in retinal clinic • S. A. Al-Ansari et al.
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a high-risk population since not only do they have established, and in many cases advanced, DR, but there is also a very high prevalence of both albuminuria and CKD. Despite this, glycaemic control was suboptimal and even though many subjects reported a diagnosis of hypertension, only 61.9% of subjects reported using ACEI or ARB. The increased risk of this population is not limited to their risk for microvascular complications of diabetes. Given their established microvascular complications, their long diabetes duration, poor glycaemic control and high prevalence of hypertension, they are at very high risk for macrovascular disease. Thus, it is disappointing that 16% of subjects continued to smoke cigarettes while only one-third of subjects reported aspirin use. Most concerning, however, was the high prevalence of smoking in T1DM subjects (32.3%). In addition to being an early marker of DN, microalbuminuria is a marker of DR and highly predictive of CVD [11] as it can reflect generalized vessel damage in the body. In addition, 78% of patients with microalbuminuria in the study reported having hypertension, which is a strong risk factor for the development and progression of DR [8]. Despite multiple studies demonstrating the importance of ACEI use and its effect on the prevention of DR and nephropathy [12–15], we found that in patients with microalbuminuria, ACEI ⁄ ARB therapy was underused. Accordingly, patients with diabetes and microalbuminuria should be targeted for more aggressive metabolic control and preventive measures. There is clearly a significant gap between clinical practice and our local guidelines, which recommend strict glycaemic control for individuals with DR, use of ACEI or ARB in subjects with DN and aspirin for subjects at high cardiovascular risk. Although patients followed up by specialists had better knowledge of HbA1c, this knowledge did not improve their overall glycaemic control, and overall diabetes knowledge seemed relatively poor. It was also striking that although almost 70% of subjects with PDR had microalbuminuria, only 20% reported a history of DN. In concordance with other studies [16], higher HbA1c values correlated with worse DR grade, necessitating better glycaemic control to aid in primary and secondary prevention of DR and other diabetes complications. Although these data are from a highly selected tertiary care setting and may not be generalizable to the general diabetes population, it is important to highlight the low utilization of proven therapies in such a high-risk group. Although physicians may be responsible for this care gap, it may in fact simply reflect the selected nature of this population, with patients with poor self-care, poor glycaemic control and low adherence to therapy at increased risk for complications. Nevertheless, it does present a challenge for healthcare delivery and raises questions of alternative approaches for subjects developing complications despite conventional care. A model where diabetes care and risk factor management were delivered integrated with therapy for retinopathy could potentially target this high-risk group. Since participants’ blood pressure was not measured in our study, the prevalence of hypertension may be underestimated. If
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anything, this would lend further weight to our contention that there is a major gap between the need for and routine use of proven antihypertensive therapies. Given the relatively high prevalence of CKD, we cannot exclude the possibility that ACEI ⁄ ARB may have been discontinued because of adverse effects, although this would not explain the low rates of aspirin use. It is unfortunate that data regarding use of lipid-lowering therapy were not collected systematically during this study, since not only is this an important component of a risk reduction strategy but it may also provide protection for eyes with DR. It would be very concerning if lipid-lowering therapy were utilized at similarly low rates in this population.
Conclusion Despite the high prevalence of both DR and microalbuminuria in diabetic subjects attending a specialist retinal clinic, knowledge, glycaemic control and use of proven therapies were suboptimal. Strategies for a comprehensive, integrated approach to education and treatment for patients with microvascular complications of diabetes should be developed and assessed.
Competing interests None to declare.
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Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1 Questionnaire Please note: Wiley-Blackwell are not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article.
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