Population-Based Measurement of Quality of Diabetes Care Using HbA1c Values in the State of Thuringia/Germany

Abstract

Introduction/Hypothesis: There remains insufficient knowledge about the quality of diabetes therapy regarding structure, process and outcome given by primary care in Thuringia, and elsewhere in Germany. The project assesses a means of determining the quality of diabetes therapy in primary care by analysis of HbA1c values within a broad territory.

Methods: HbA1c tests of Thuringian patients were analysed by 20 participating medical laboratories between January 1 and March 31, 2002; each HbA1c test was identified by the postal code of the Thuringian General Practitioner (GP) who ordered the test and adjusted by a standardisation procedure (mean normal of healthy subjects 5 %). The German state of Thuringia (population of 2 421 871) consists of 23 urban and rural districts. This format was also used in the present study.

Results: Twenty participating laboratories contributed 59 702 HbA1c tests from diabetic patients in Thuringia. Adjusted mean HbA1c of entire Thuringia: 6.75 %, 36.4 % of all HbA1c tests were above 7.0 % and 3,0 % of all HbA1c values above 10.0 %. Regional percentage of HbA1c tests above 7.0 % ranged between 28.2 % and 47.3 %. Regional percentage of HbA1c tests above 10.0 % ranged between 1.8 % and 4.8 %. Subgroup analyses comparing urban vs. rural districts showed significantly lower mean HbA1c (6.72 % vs. 6.75 %, CI 0.01 - 0.06, p < 0.01) and percentage of HbA1c tests above 7 % (8.19 % vs. 8.24 %, CI 0.01 - 0.08, p < 0.01) in urban areas.

Conclusions: Mean HbA1c as an indicator of glycaemic control of diabetes patients in primary care in Thuringia was good. The percentage of patients who need immediate medical intervention to prevent acute complications varied between districts, which is indicative for differences in quality of diabetes care in Thuringia. However, the proposed method is still experimental and has not yet been evaluated. Consequently, considerable bias might influence the results.

Key words

Diabetes mellitus - HbA1c - public health care - epidemiology - outcome quality

References

• 1 Abbott R D, Donahue R P, Kannel W B, Wilson P W. The impact of diabetes on survival following myocardial infarction in men vs. women. The Framingham Study.  JAMA. 1988;  260 3456-3460 Erratum in:.  JAMA. 1989;  261 1884
• 2 The ALLHAT Collaborative Research Group . Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs. diuretic. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).  JAMA. 2003;  288 2981-2997
• 3 Amos A F, McCarty D J, Zimmet P. The rising global burden of diabetes and its complications: estimates and projections to the year 2010.  Diabetic Medicine. 1997;  14 7-85
• 4 Bagust A, Hopkinson P K, Maslove L, Currie C J. The projected health care burden of Type 2 diabetes in the UK from 2000 to 2060.  Diab Med. 2002;  19 (Suppl 4) 1-5
• 5 Berger M. Mühlhäuser I. Implementation of intensified insulin therapy. A european perspective.  Diabet Med. 1995;  12 201-208
• 6 Berger B, Stentstrom G, Sundkvist G. Incidence, prevalence, and mortality of diabetes in a large population. A report from the Skaraborg Diabetes Registry.  Diab Care. 1999;  22 773-778
• 7 Bertoni A G, Krop J S, Anderson G F, Brancati F L. Diabetes-related morbidity and mortality in a national sample of US elders.  Diab Care. 2002;  25 471-475
• 8 Brun E, Nelson R G, Bennett P H, Imperatore G, Zoppini G, Verlato G, Muggeo M. Diabetes duration and cause-specific mortality in the Verona Diabetes Study.  Diab Care. 2000;  23 1119-1123
• 9 Colman P G, Goodall G I, Garcia-Webb P, Williams P F, Dunlop M E. Glycohaemoglobin: a crucial measurement in modern diabetes management. Progress towards standardisation and improved precision of measurement. Australian Diabetes Society, the Royal College of Pathologists of Australia and the Australian Association of Clinical Biochemists [consensus development conference].  Med J Aust. 1997;  167 96-98
• 10 DAFNE Study Group . Training in flexible, intensive insulin management to enable dietary freedom in people with type 1 diabetes: dose adjustment for normal eating (DAFNE) randomised controlled trial.  BMJ. 2002;  5: 325 746
• 11 The Diabetes Control and Complication Trial Research Group (DCCT) . The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus.  N Engl J Med. 1993;  329 977-986
• 12 Dunstan D W, Zimmet P Z, Welborn T A, De Courten M P, Cameron A J, Sicree R A, Dwyer T, Colagiuri S, Jolley D, Knuiman M, Atkins R, Shaw J E. The rising prevalence of diabetes and impaired glucose tolerance - the Australien diabetes, obesity and lifestyle study.  Diab Care. 2002;  25 829-834
• 13 El-Agouza I, Abu Shahla A, Sirdah M. The effect of iron deficiency anaemia on the levels of haemoglobin subtypes: possible consequences for clinical diagnosis.  Clin Lab Haematol. 2002;  24 285-289
• 14 Fluckiger R, Harmon W, Meier W, Loo S, Gabbay K H. Hemoglobin carbamylation in uremia.  N Engl J Med. 1981;  304 823-827
• 15 Ford E S, De Stefano F. Risk factors for mortality from all causes and from coronary heart disease among persons with diabetes. Findings from the National Health and Nutrition Examination Survey I. Epidemiologic follow-up study.  Am J Epi. 1991;  133 1220-1230
• 16 Green A, Gale E AM, Patterson C C. Incidence of childhood-onset insulin-dependent diabetes mellitus: the EURODIAB ACE study.  Lancet. 1992;  339 905-909
• 17 Grusser M, Hoffstadt K, Jorgens V. Preventive care for early detection of diabetes mellitus complications: a model project in Wolfsburg (Article in German).  ZaeFQ. 2000;  94 411-416
• 18 Gu K, Cowie C C, Harris M. Mortality in adults with and without diabetes in a national cohort of the U. S. population, 1971 - 1993.  Diab Care. 1998;  21 1138-1145
• 19 Harris M, Hadden W C, Knowlen P H. Gennett: Prevalence of diabetes and impaired glucose tolerante and plasma glucose levels in U. S. population aged 20 - 74 yr.  Diabetes. 1987;  36 523-534
• 20 Heart Protection Study Collaborative Group . MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20 536 high-risk individuals: a randomised placebo-controlled trial.  Lancet. 2002;  360 7-22
• 21 Hoberman H D, Chido S M. Elevation of the hemoglobin A₁ fraction in alcoholism.  Alcoholism Clin Experim Res. 1982;  6 260-266
• 22 Junghänel J, Netzer, Müller U A. Prävalenz Diabetischer Folgeerkrankungen als Qualitätsmerkmal der Diabetesbehandlung in der Hausarztpraxis in Thüringen und Mecklenburg-Vorpommern.  Diab Stoffw. 2001;  10 (Suppl 1) 109
• 23 Karvonen M, Tuomilehto J, Libman I, LaPorte R. A review of the recent epidemiological data and the worldwide incidence of type 1 (insulin-dependent) diabetes mellitus.  Diabetologia. 1993;  36 883-892
• 24 King H, Aubert R E, Herman W H. Global burden of diabetes, 1995 - 2025: prevalence, numerical estimates, and projections.  Diab Care. 1998;  22 1414-1431
• 25 Liebl A, Neiss A, Spannheimer A, Reitberger U, Wieseler B, Stammer H, Goertz A. Complications, co-morbidity, and blood glucose control in type 2 diabetes mellitus patients in Germany - results from the CODE-2 study.  Exp Clin Endocrinol Diabetes. 2002;  110 10-16
• 26 Mooy J M, Grootenhuis P A, de Vries H, Valkenburg H A, Bouter L M, Kostense P J, Heine R J. Prevalence and determinants of glucose intolerance in a Dutch caucasian population. The Hoorn Study.  Diabet Care. 1995;  18 1270-1273
• 27 Müller U A, Junghänel J, Köhler S, Köhler M, Schumann M. Quality of diabetes care in a general practice network.  Exp Clin Endocrinol Diabetes. 2000;  108 (Suppl 1) S 163
• 28 Müller U A, Femerling M, Risse A. for the Working group of structured Diabetes therapy of the German Diabetes Association . HbA1c and severe hypoglycemia after intensified treatment and education of 10 000 type-1-diabetec patients. Results of a ten years nationwide quality-circle. Oral lecture on the 37th Annual Meeting of the EASD, Glasgow 9. - 13. 9. 2001.  Diabetologia. 2001;  44 (Suppl 1) A16
• 29 Ohkubo Y, Kishikawa H, Araki E, Miyata T, Isami S, Motoyoshi S, Kojima Y, Furuyoshi N, Shichiri M. Intensive insulin therapy prevents the progression of diabetic microvascular complications in Japanese patients with non-insulin-dependent diabetes mellitus: a randomized prospective 6-year study.  Diabetes Res Clin Pract. 1995;  28 103-117
• 30 Panzram G, Zabel-Langhennig R. Prognosis of diabetes mellitus in a geographically defined population.  Diabetol. 1981;  20 587-591
• 31 Rathmann W, Haastert B, Icks A, Löwel H, Meisinger C, Holle R, Giani G. High prevalence of undiagnosed diabetes mellitus in Southern Germany: Target populations for efficient screening. The KORA survey 2000.  Diabetologia. 2003;  46 182-189
• 32 Reichard P, Pihl M, Rosenqvist U, Sule J. Complications in IDDM are caused by elevated blood glucose levels: The Stockholm Diabetes Intervention Study (SIDS) at 10-year follow up.  Diabetologia. 1996;  39 1483-1488
• 33 Saemann A, Koehler S, Klinger R, Mohr Ch, Mueller U A. Mapping HbA1c values as a quality measure in the primary care of diabetes patients in Thuringia, Germany (in German).  ZaeFQ. 2002;  96 615-620
• 34 Scandinavian Simvastatin Survival Study . Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4 S).  Lancet. 1994;  19 (8934) 1383-1389
• 35 Schiel R, Muller U A, Sprott H, Schmelzer A, Mertes B, Hunger-Dathe W, Ross I S. The JEVIN trial: A population-based survey on the quality of diabetes care in Germany: 1994/1995 compared to 1998/1999.  Diabetologia. 1997;  40 1350-1357
• 36 Schulze J, Kunath H, Rothe U, Range U, Prettin C, Verlohren H J, Fischer S. Quality of diabetes management in the free Saxony state - scientific evaluation of the Saxony model for managing diabetes. EVA group (in German).  Gesundheitswesen. 1996;  58 (Suppl 2) 144-148
• 37 SPSS ©. SPSS Inc. Chicago, Illinois, USA; 2002
• 38 Stede D. on behalf of The Thurigian Department of Statistics .Group IV.3 (Population). Erfurt; The Free State of Thurigia 2002
• 39 Tarim O, Kucukerdogan A, Gunay U, Eralp O, Ercan I. Effects of iron deficiency anemia on hemoglobin A1 c in type 1 diabetes mellitus.  Pediatr Int. 1999;  41 357-362
• 40 UK Prospective Diabetes Study Group . Efficacy of atenolol and captopril in reducing risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 39.  BMJ. 1998 a;  317 (7160) 713-720
• 41 UK Prospective Diabetes Study Group . Intensive blood-glucose control with sulfonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).  Lancet. 1998 b;  352 837-853
• 42 UK Prospective Diabetes Study Group . Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38.  BMJ 1998 c; 317 (7160): 703 - 713; Erratum in BMJ. 1999;  318 (7175) 29
• 43 Vincent Group . Diabetes care and research in Europe. The St. Vincent Declaration.  Diabet Med. 1989;  7 360
• 44 West of Scotland Coronary Prevention Study . Identification of high-risk groups and comparison with other cardiovascular intervention trials.  Lancet. 1996;  348 (9038) 1339-1342
• 45 Yusuf S, Sleight P, Pogue J, Bosch J, Davies R, Dagenais G. Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients. The Heart Outcomes Prevention Evaluation Study Investigators.  N Engl J Med 2000; 342: 145 - 153; Erratum in N Engl J Med 2000; 342: 1376 and N Engl J Med. 2000;  342 748