Day After the Night Before Influence of evening alcohol on risk of hypoglycemia in patients with type 1 diabetes TRISTAN RICHARDSON, BSC, MRCP 1 MELANIE WEISS, RGN 1 PETER THOMAS, PHD 2 DAVID KERR, MD, FRCP 1 T here is no evidence to suggest that individuals with type 1 diabetes adopt a different approach to their use of alcohol than the rest of the popu- lation. Nevertheless, in patients treated with insulin, alcohol has been implicated in up to one-fifth of hospital attendances with hypoglycemia (1). Recently, in a lab- oratory-based study, Turner et al. (2) re- ported that ingestion of alcohol with an evening meal increased the risk of hypo- glycemia the next morning in patients with type 1 diabetes. However, this study was small, patients were admitted to a re- search unit, their “usual” insulin doses were reduced at meal times, and the over- night insulin was administered intrave- nously in a controlled environment. To date there has been no study examining the effect of alcohol in free-living patients with type 1 diabetes over a 24-h period. RESEARCH DESIGN AND METHODS — We studied 16 free- living patients with type 1 diabetes aged 39  7 years, with a duration of diabetes of 15  11 years, who consumed alcohol on a regular basis (28 units/week). All gave written informed consent for the study after approval from the local re- search ethics committee. All had normal awareness of hypoglycemia and stable glycemic control (HbA 1c 8.1  1.0%). The patients wore the continuous glucose monitoring system (CGMS) (Medtronic Minimed, Minneapolis) for 36 h on two occasions separated by 2 weeks. On both occasions they continued with their usual insulin and four-times-daily home blood glucose monitoring. The patients were provided with either placebo (orange juice alone) or vodka (0.85 g/kg) and or- ange juice to produce peak alcohol levels of 80 –100 mg/100 ml ingested over 60 min with identical standardized evening meals (carbohydrate content 120 –150 g). Both patients and investigators were blinded to the composition of the supple- mental drink. An independent party not involved with the study randomized the patients. The same dose of insulin was given (calculated per carbohydrate con- tent of the meal) with the meal and before bed. On the 2nd day, the patients ab- stained from alcohol and the CGMS was removed 24 h after the standardized meal. Over the 2 CGMS days, events such as meals, insulin doses, exercise, sleep, and hypoglycemic events were recorded. The study was repeated 2 weeks later with the other drink supplied. The definition of in- terstitial hypoglycemia (3) was based on the glycemic thresholds at which there was activation of the counterregulatory hormone cascade and onset of neurogly- copenia. RESULTS — CGMS data were avail- able from all 16 subjects. There were two patient-sensor failures during the study (error 28%). The specific arm of the study (i.e., alcohol or placebo) where the sensor had been invalid was subsequently repeated. After the alcoholic drink, pa- tients reported more than twice as many hypoglycemic episodes per day than after the placebo drink [self-reported hypogly- cemic episodes: mean (range) 1.3 (0 – 4) with alcohol vs. 0.6 (0 –2) with placebo, P = 0.02 using Wilcoxon’s test]. There were no reported episodes of severe hy- poglycemia requiring the assistance of an- other individual. Carbohydrate intake was not different during the 24 h in either group [average (range) 418 g with alcohol (195–1,350) and 369 g (180 –1,000) with placebo, P = 0.15 using Student’s t test]. Overall, the average interstitial glucose level was 1.2 mmol/l (95% CI 0.8 –1.6) lower with alcohol compared with pla- cebo [7.4 mmol/l (7.1–7.7) vs. 8.6 mmol/l (8.2–9.0), P = 0.02 using Student’s t test]. While this varied with time and magnitude throughout the 24 h (Fig. 1), it was the prevailing glucose that deter- mined the risk of hypoglycemia. This translated into an increased risk of inter- stitial hypoglycemia throughout the 24-h period, with a persistent risk of hypogly- cemia continuing into the next day. CONCLUSIONS — There is a lack of consistent advice given to patients con- cerning alcohol and the potential risk of low blood glucose levels. In this study, ingestion of modest amounts of alcohol with an evening meal was associated with an increased risk of delayed hypoglyce- mia in patients with type 1 diabetes. Alcohol may be associated with hypogly- cemia in a number of ways. First, inges- tion of even small amounts may impair the ability of the individual to detect the onset of hypoglycemia at a stage when they are still able to take appropriate ac- tion, i.e., eat carbohydrates. Second, hy- poglycemia per se may be mistaken for intoxication by third parties with legal as well as health consequences. Third, alco- hol has been shown in some studies to directly impair the hormonal counter- regulatory responses to low blood glucose levels (4). Fourth, recent data indicate that small amounts of alcohol can aug- ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● From the 1 Bournemouth Diabetes & Endocrine Centre, Royal Bournemouth Hospital, Bournemouth, U.K.; and the 2 Dorset Research and Development Support Unit, Poole Hospital & Bournemouth University, Bournemouth, U.K. Address correspondence and reprint requests to Dr. Tristan Richardson, BDEC, Royal Bournemouth Hospital, Castle Lane East, Bournemouth, BH7 7DW. E-mail: tristan.richardson@rbch.nhs.uk. Received for publication 22 March 2005 and accepted in revised form 24 March 2005. Abbreviations: CGMS, continuous glucose monitoring system. A table elsewhere in this issue shows conventional and Syste `me International (SI) units and conversion factors for many substances. © 2005 by the American Diabetes Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Pathophysiology/Complications B R I E F R E P O R T DIABETES CARE, VOLUME 28, NUMBER 7, JULY 2005 1801 Downloaded from http://diabetesjournals.org/care/article-pdf/28/7/1801/568377/zdc00705001801.pdf by guest on 26 December 2021