ALGOS - An algorithm guiding patients with type 1 diabetes treated with continuous subcutaneous insulin©
Previous studies have shown that strict metabolic control reduces long term complications in Type I diabetes (T1D) patients [1,2]. These studies involved self-monitored blood glucose fingerprick readings, with frequent, weekly input by health-care professionals. The aim was to maintain near normal glucose levels while minimizing hypoglycemia. Unfortunately, such intensive input by health-care professionals is not readily feasible in clinical practice.
Currently insulin doses in most T1D patients are determined by the patient in consultation (usually several times a year) with the diabetes care team, largely based on self-monitored blood glucose readings. Such readings provide only single “snapshots”, of glucose readings at selected times, usually before meals and bed during the day, with post-meal and overnight readings being less frequent. The frequency of self-monitored blood glucose readings has been shown to correlate inversely with HbA1c levels [4].
Real time-continuous glucose monitoring (RT-CGM) is patient-oriented and enables tracking of interstitial glucose levels on a continuous basis. RT-CGM devices which may be integrated with a continuous subcutaneous insulin infusion (CSII) device have recently become available [5, 6]. Interstitial glucose readings, with direction and rate of change, are displayed every five minutes and can be linked to alarms for low and high glucose levels. RT-CGM data is stored and can be uploaded to a computer or website and reviewed retrospectively.
At present RT-CGM devices cannot directly determine insulin delivery. Changes in insulin dosing must be initiated by the patient or carer who interprets the glucose information provided. Previous studies have examined the impact of RT-CGM upon glycemia with some [7-10] but not all [11] demonstrating benefit. However, maladaptive user responses to RT-CGM are possible in the absence of appropriate guidance.
Studies to date show that patient directed use of RT-CGM by CSII-treated T1D subjects do result in a reduction in HbA1c levels over 12 weeks [12]. An algorithm has been developed to guide CSII-user responses to RT-GCM to enhance this benefit. The algorithm is designed to guide patients in their decisions regarding immediate responses to glucose levels and proactive changes to pump basal insulin settings, insulin to carbohydrate ratios, and correction factors which determine longer term glycemia. Following algorithm education, patients are provided with a written form of the algorithm along with a wallet card summarizing reactive guidelines and a wall chart summarizing proactive changes to assist their review of RT-GCM uploads. The algorithm, wallet card and wall chart can be downloaded using the links below.
The algorithm was developed and evaluated in a major investigator-initiated study, supported by Medtronic Australasia and the Diabetes CCRE, involving the following health professionals listed alphabetically:
| Investigator | Centre |
| Professor James Best* | University of Melbourne, Department of Medicine St Vincent's Hospital |
| Meagan Buszard CDNE | Department of Diabetes, Southern Health, Clayton |
| A/Professor Fergus Cameron | Department of Endocrinology and Diabetes, Royal Children's Hospital and Murdoch Children's Research Institute, Melbourne |
| A/Professor Steve Farish | University of Melbourne, Department of Medicine, St Vincent's Hospital |
| Emily Fitzgerald CDNE | Department of Diabetes and Endocrinology, The Royal Melbourne Hospital |
| A/Professor Shane Hamblin | Department of Endocrinology and Diabetes, Western Hospital, Footscray, Melbourne |
| Jodie Horsborough CDNE | University of Melbourne, Department of Medicine St Vincent's Hospital |
| Rebecca Humphries CRNE | Department of Endocrinology and Diabetes, Royal Children's Hospital and Murdoch Children's Research Institute, Melbourne |
| A/Professor Alicia Jenkins* | University of Melbourne, Department of Medicine St Vincent's Hospital |
| Dr Bala Krishnamurthy* | University of Melbourne, Department of Medicine St Vincent's Hospital |
| Adam Lamendola CDNE | Department of Diabetes, Southern Health, Clayton |
| Dr Michelle O'Connell | Department of Endocrinology and Diabetes, Royal Children's Hospital and Murdoch Children's Research Institute, Melbourne |
| Dr David O'Neal* | University of Melbourne, Department of Medicine St Vincent's Hospital |
| Karen Palmer CDNE | Department of Diabetes and Endocrinology, The Royal Melbourne Hospital |
| A/Professor Christine Rodda | Department of Diabetes, Southern Health, Clayton |
| Cheryl Steele CDNE | Department of Endocrinology and Diabetes, Western Hospital, Footscray, Melbourne |
| Kathy Steele CDNE | Department of Diabetes and Endocrinology, The Royal Melbourne Hospital |
| Professor Helena Teede | Department of Diabetes, Southern Health, Clayton |
| Meredith Williams CDNE | Department of Diabetes, Southern Health, Clayton |
*Members of the Diabetes CCRE.
Sixty Australians, including adults and adolescents, with Type 1 diabetes partnered with the health care professionals to enable the study. The results show that in adults using the algorithm in addition to their insulin pump and real-time glucose sensor data, their HbA1c improved significantly, but there was no significant change in HbA1c levels in non-algorithm users. In addition, after 16 weeks of intervention, the proportion of adults with the desired HbA1c of 7% was significantly greater in algorithm users than non-users.
ALGOS evaluation study results were presented at the 2008 European Association for the Study of Diabetes meeting (Rome, Italy 7-11 September 2008), the American Diabetes Associations' 69th Scientific Sessions (New Orleans, USA June 6-9, 2009) and the forthcoming 2009 Australian Diabetes Society Meeting (Adelaide, Australia August 26-28, 2009). The ADA oral presentation slides can be downloaded using the link below. Insulin pump using patients should discuss their potential use of the algorithm with their diabetes care team so that treatment can be individualized. The ALGOS investigators can be contacted by health care professionals for further information, at enquiries@diabetesccre.unimelb.edu.au.
References
1. The DCCT Research Group. 1993. 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. 329:977-86.
2. The Diabetes Control and Complications Trial/ Epidemiology of Diabetes Intervention and Complications (DCCT / EDIC) Study Research Group. 2005. Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. N Engl J Med. 353: 2643-53.
3. Brink SJ, Moltz K. 1997. The message of the DCCT for Children and Adolescents. Diabetes Spectrum. 10:259-267.
4. Haller MJ, Stalvey MS, Silverstein JH. 2004. Predictors of control of diabetes: Monitoring may be the key. J Paediatrics. 144: 660-661.
5. Mastrototaro JJ, Cooper KW, Soundararajan G, Sanders JB, Shah RV. 2006. Clinical experience with an integrated continuous glucose sensor / insulin pump platform: a feasibility study. Adv Ther. 23: 725-732.
6. Mastrototaro JJ, Soundararajan G, Cooper K, Shah R. 2007. Accuracy of real time continuous glucose monitoring in the Minimed Paradigm system (abstract). Diabetes 56(Suppl 1): 0422-P.
7. Deiss D, Bolinder J, Riveline J-P, Battelino T, Bosi E, Tubiana-Rufi N, Kerr D, Phillip M. 2006. Improved glycemic control in poorly controlled patients with type 1 diabetes using real-time continuous glucose monitoring. Diabetes Care. 29: 2730- 2732.
8. O'Connell MA, Donath S, O'Neal D, Colman P, Ambler G, Jones T, Davis E, Cameron F. 2009. Glycaemic impact of patient-led use of sensor guided pump therapy in type 1 diabetes: a randomised controlled trial. Diabetologia. In Press.
9. Diabetes Research in Children Network (DirecNet) Study Group. 2007. Continuous glucose monitoring with Type 1 Diabetes. J Pediatrics. 151: 388-393.
10. The Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. 2008. Continuous Glucose Monitoring and Intensive Treatment of Type I Diabetes. N Engl J Med. 359:1464-1476.
11. Weinzimer S, Dongyuan X, Tansey M et al. 2008. Diabetes Research in Children network (Direc Net) Study Group. FreeStyle navigator continuous glucose monitoring system use in children with type 1 diabetes using glargine based multiple daily dose regimens: results of a pilot trial Diabetes research in Children Network (DirecNet) Study Group. Diabetes Care. 31: 525-527.
12. Hirsch I B, Abelseth J, Bode B W, Fischer J S, Kaufman F R, Mastrototaro J, Parkin C G, Wolpert H A, Buckingham B A. 2008. Sensor-Augmented Insulin Pump Therapy: Results of the First Randomised Treat-to-Target Study. Diabetes Technology & Therapeutics 10: 377-383.