April 27, 2010
A1c (Glycohemoglobin, HgbA1c), Hypoglycemia
Question from Ypsilanti, Michigan, USA:
My question is about A1c numbers. I was diagnosed when I was nine years old, which was quite a while ago, and one of the biggest things I remember from then was how desperately my pediatrician wanted us to avoid any high blood sugars. In fact, the doctors concentrated on having lower blood sugars to avoid future complications far more than they worried about hypoglycemia. I had been pumping since 2001, and last month, while hospitalized for hypoglycemia due to unrelated stomach issues (I wasn't able to eat and what I did eat, I threw up), which are still continuing to the point of having an appointment with a gastroenterologist in a couple hours, my blood sugar nosedived to 14 mg/dl [0.8 mmol/L]. I fell/passed out (my blood sugar from a fingerstick read 14 mg/dl [0.8 mmol/L] when "they" got to me) and I even ended up with a broken ankle (resulting in surgery complete with eight screws, a pin and a plate). Because we now live less than half an hour away, I've switched to the University of Michigan health system for all of my medical needs but I'm slightly freaked out by how high they want my A1c to be. My last two were 5.4 and 5.8 respectively (my old endocrinologist felt 5.4 was too low, but was fine with 5.8), While I was hospitalized, doctors at the University of Michigan asked me to give my pump up for a while (until I could go for pump re-training as it were). I agreed. We also realized, at that time, that after losing 130 pounds, no one had changed my basal rate nor my insulin to carbohydrate ratio after my weight loss. In fact, I've even gained 20 to 30 pounds back because of the lows. I'm going back on my pump today with the help of a diabetes nurse educator who is absolutely wonderful, but I've been told they want my next A1c to be as high as 7! I've spent the last five or so years concentrating on keeping my blood sugar between 70 and 90 mg/dl [3.9 and 5.0 mmol/L]. I felt great there and got awesome A1cs according to my last endocrinologist. I realize now that 70 mg/dl [3.9 mmol/L] may have been a little too low as I never recognized a low until I was at about 30 mg/dl [1.7 mmol/L] or so. Over the last month (while I've been off my pump,) I've learned to be okay up to about 130 mg/dl [7.3 mmol/L] instead feeling completely sluggish and on the verge of DKA at about 150 mg/dl [8.3 mol/L] and I have recognized when I've started to drop around 60 mg/dl [3.3 mmol/L](big improvement!). However, I'm a bit worried about allowing an A1c that seems so high (7) for a lot of reasons but, mostly, it's because I want to have a long and complication-free life. I realize I was running too low, especially after the nurse educator downloaded my home monitor and informed me that I was having more lows than 95 percent of the patients she sees. A big part of that, of course, was due to nothing being changed dosage wise after losing as much weight as I did. The nurse educator also told me that they want my A1c right around 6.5 or even 7 since people in my position are at a three times higher death rate from low blood sugars. I do realize my numbers have been running too low for a while, but 7? It just seems a little to high to me so I would like your opinions please. Seriously, when did they stop worrying so much about hyperglycemia and start worrying so much about hypoglycemia? I do know and am aware that neither are good, but it just seems to me anyway, that "they" now worry a lot more ANY lows as opposed to running a little higher.
Like everything, knowledge comes with experience. You are really talking about walking the line between hyperglycemia with complications and hypoglycemia and immediate changes in mental status. It turns out that as insulin delivery got easier with pumps and sensors and better education, the frequency of hypoglycemia went up. The landmark study, The Diabetes Control and Complications Trial (DCCT), published in 1993, demonstrated that tight control was associated with over a 70% reduction in the microvascular complications, including retinopathy, neuropathy, and nephropathy. The nine-year average HbA1c in the tight control group was 7.2%, while the control group was 9%. However, there was a three-fold increase in severe hypoglycemic reactions. It turns out that more lows allow more lows to occur. Therefore, the process of severe hypoglycemia unawareness builds on its self. The good news is that it has been shown that by avoiding lows for one to two months, you can get some of your ability to sense lows back and be able to protect yourself (just as you have seen). In addition, the recent ACCORD and VADT trials have shown that intensive control in these groups led to increase cardiovascular death, thought to be related to hypoglycemia. It is as if you can really bring the sugars down and have good control for roughly 15 years or so, but a change to tight control after that may have detrimental effects. Getting back to you, I would say the information you have received has been good. You have gotten your ability to sense lows back. This will safeguard you from serious lows and loss of consciousness. At the same time, there is the benefit of keeping your blood glucose down to prevent microvascular complications. I do not think that there is a mixed message. Rather, it is a fine line between keeping glucose levels too low or too high. You sounded like you were clearly too low.