Type 2 Diabetes Mellitus

The Management of Type 2 Diabetes

This starts the first of several disease-specific posts.  In primary care, the vast majority of the care I provide is the management of chronic disease.  Unfortunately, in this country, Type 2 diabetes is one of the most common chronic diseases we manage. 

Type 2 diabetes is basically, at the physiologic level, a problem of insulin resistance.  Insulin is a hormone made by special cells that hang out in the pancreas (called beta-islet cells).  Insulin is required to allow sugar in the blood stream to move out of the bloodstream and into the cells to be used as metabolic fuel.  I frequently use the analogy of insulin molecules as "keys" to unlock the "doors" between the bloodstream and the cells, allowing the sugar to enter, for example, a muscle cell.

Where a "normal" nondiabetic patient may require one "key" of insulin to open the door to the muscle cell, someone with Type 2 diabetes requires perhaps three insulin keys to open the door.  Therefore, the diabetic patient requires more insulin to do the same job as a "normal" person.  Therefore the diabetic patient's beta-islet cells are cranking out insulin at relatively high levels. 

Insulin at high levels is a bad actor.  It encourages other hormones to run at high levels, and between these bad actors, encourages the deposition of fat INSIDE the abdomen as well as all over.  So keeping these hormones at high levels makes people gain weight, especially around their bellies.  Interestingly, this internal abdominal fat then has further metabolic effects to magnify the relative insulin resistance that already exists.  So the problem snow-balls. 

Type 2 diabetes is a problem of heredity, age, and weight.  I tell my patients who have perhaps recently been diagnosed with type 2 diabetes, especially if they come from a family with type 2 diabetes, that they cannot do anything about their relatives, and they cannot do anything about their age, but they CAN do something about their weight.  Weight is the most important variable that controls whether or not a patient will be diabetic. 

I have patients in my practice who have in the past had full-fledged diabetes, but because of excellent dietary and exercise and lifestyle interventions, no longer have diabetes.  They may have seen themselves become diabetic when their weight poked up around, for example, 250 lbs.  They became non-diabetic when their weight dropped under 210 lbs.  Then they might get "lazy" and allow their weight to come up and by the time they are 230 lbs they are again fully diabetic.  So they sort of have a threshold of weight beyond which they are fully diabetic.  Unfortunately, as that patient ages, that weight threshold may slowly fall. 

Type 2 diabetes IS curable in some sense of the word.  It can go away if the patient loses enough weight.  Unfortunately, weight loss is one of the most difficult interventions for most people to do.   (Weight loss will be discussed in more detail in another post.)  The point is, as with most chronic disease, LIFESTYLE changes have a huge impact, but most people find those changes absolutely daunting. 

A patient is diagnosed as having type 2 diabetes when their fasting blood sugar (glucose) is over 125.  Most normal people have a fasting glucose between 70 and 99.  The zone of fasting blood sugars between 100 and 125 is called "prediabetes."  Actually, the official "gold standard" test for type 2 diabetes is a fasting 2 hour oral glucose tolerance test.  Another way of diagnosing type 2 diabetes is by getting a hemoglobin A1c test with a result greater than or equal to 6.5% .  More about that later.

So what is so bad about having a fasting blood sugar level over 125?  The issue is the metabolic damage caused by having these constantly high sugar levels.  The metabolic damage causes abnormal changes to tiny blood vessels all over the body, as well as other damage. 

Probably the most common site of damage I see in poorly-controlled diabetic patients is nerve damage, called peripheral neuropathy.  Peripheral neuropathy involves damage to very fine sensory nerves with a predilection for the feet.  So these patients start to notice that they may not have normal sensation in their feet, typically the toes or near the toes.  They report odd sensations of the feet feeling hot all the time, or a "buzzing" or tingling sensation, or sometimes just no sensation at all.  Having the gradual loss of sensation is almost the most dangerous problem because the patient does not know they are losing sensation. 

If you can't feel things in your feet, you may develop a small injury--say a small rock in your sock.  It causes a small sore that opens up.  Since you can't feel it, you don't know it is there.  It smolders and gets infected.  You still don't know it is there.   If the infection goes too long ignored, the infection can make its way into the bones of the foot and turn into a potentially deadly bone infection called osteomyelitis.  Often the only effective treatment for that is an amputation.  This is the most common scenario that occurs when you hear of a diabetes patient losing a part of their foot or leg. 

Sometimes the nerve damage involves the autonomic nervous system.  This is part of the nervous system that runs in the background--keeping your GI tract working and your bladder functioning and, if you're a male, your ability to maintain an erection.  When the autonomic nervous system becomes affected, it can cause diabetic gastroparesis, where the GI tract just sort of stops moving.  This fortunately, is pretty rare. 

Other types of damage from the abnormal metabolism of high sugar levels include retinal eye damage.  Termed diabetic retinopathy, this is characterized by abnormal growth of tiny blood vessels in the retina of the eye, which can leak or rupture or otherwise cause all kinds of havoc with the retina, and thus possible blindness.  This is why we ask our diabetes patients to see an eye specialist at least yearly to identify the early changes of diabetes on the retina.

The kidneys are another important site of damage from high sugar levels.  Some of the earliest signs of damage to the kidneys is the leakage of small proteins into the urine, that should normally NOT be allowed into the urine.  Subsequent kidney damage can continue, ultimately resulting in gradual kidney failure, to the point of requiring dialysis.  Fortunately, this degree of damage from diabetes is relatively rare. 

Having higher than normal blood sugar levels also interestingly affects immune status.  Patients with type 2 diabetes are more prone to superficial infections of the skin, such as abscesses or fungal infections. 

The actual number one risk to health and well-being with type 2 diabetes is the significant increase in heart attacks and strokes that diabetes carries.  The metabolic damage of diabetes accelerates the laying-down of cholesterol plaque in the arteries of the heart or leading to the brain, thus dramatically increasing the risk of blocked arteries in the heart or pieces of plaque breaking off and causing a stroke in the brain. 

Therefore, we as physicians get very aggressive in patients with type 2 diabetes to reduce OTHER heart disease and stroke risk factors such as smoking and high blood pressure and cholesterol.   

We are so well-acquainted with the risks and complications of type 2 diabetes that we have excellent evidence-based guidelines that are established.  We know that if we can keep our patients within these management guidelines, that we can dramatically reduce their risk of diabetes complications like nerve damage, blindness, kidney failure, infections, heart attacks, and strokes. 

The Guidelines: 

Whenever I see a patient with type 2 diabetes, I want to know that the following issues are addressed:

1.  Where is their Hemoglobin A1c?  Hemoglobin A1c values are a blood test that tells us the average blood sugar in this patient over the past 3 months.  A1c values range from around 4 to over 12.  An A1c value of 7.0 corresponds to an average blood sugar over the past 3 months of about 150.  We know that statistically we see significantly fewer complications in patients who keep their average sugar levels under 150 (thus A1c value under 7.0).  In our patients over 70, we relax that rule and recommend keeping the A1c under 8.0, simply because we run a bigger risk of problems with too tight of control in older patients. 

2.  What is their blood pressure?  Because heart attacks and stroke are the number one killers of diabetes patients, we want to keep blood pressure well controlled.  Having out-of-control blood pressure increases the risk of heart attack and stroke, as well as eye and kidney damage.  So we want our diabetes patients to monitor their blood pressures at home and hopefully keep the upper number under 130 and the lower number under 85.  Quite often this requires additional medication to keep the blood pressure under control.

It turns out though, that two families of blood pressure medications also serve "double-duty" to help protect the kidneys against diabetic kidney damage:  The ACE-Inhibitor family (lisinopril and its siblings), and Angiotensin-Receptor Blockers (ARBs) such as Diovan and many others. 

3.  What is their LDL cholesterol?  LDL cholesterol (low-density lipoprotein) is the "bad" cholesterol responsible for clogging up arteries.  LDL values over 100 in patients with diabetes are associated with higher risk for heart attack and stroke.  In a patient with NO diabetes and no other heart disease risk factors, we might accept LDL levels up to 160.  But we keep a much tighter standard for diabetes patients.  This often means that we may recommend prescription medication cholesterol-lowering medication to get LDL cholesterol down under 100 in these diabetic patients.  I will check cholesterol tests at least once a year in my patients with diabetes. 

4.  Are they taking 81 mg of aspirin daily?  81 mg of regular aspirin has been shown to reduce the risk of first heart attack and stroke in patients at risk.  This low dose is rarely associated with any bleeding risk or stomach lining damage.  However, we would NOT recommend this obviously in patients with an aspirin allergy or who may have experienced chronic stomach lining irritation (gastritis) or bleeding ulcers. 

5.  Have they had an appropriate diabetic eye exam in the past year?  Diabetic retinopathy is often very silent--that is, may show no symptoms until disaster strikes with an acute bleeding episode into the retina, with sudden vision loss.  An ophthalmologist (eye physician) can do an appropriate exam (as can many optometrists--non MD eye doctors) to identify the early changes of diabetes damage to the eye before problems occur, and when interventions may work to prevent further damage. 

6. Have they had a urine test for microalbumin?  Called a "urine microalbumin/creatinine ratio," this nonfasting urine test can pick up the very early minor leakage of small proteins in the urine that may be heralding the early development of diabetic kidney damage. 

7. Have they had the nerves in their feet tested?  We can check for early peripheral neuropathy by using a small plastic thread like fishing line to see if sensation is normal in the feet.  Sometimes using a vibrating tuning fork is also helpful.  If we find that the ability of the feet to detect these subtle sensory changes is declining, we can be more aggressive with monitoring for foot damage.  There are some types of treatment for diabetic nerve damage, but they are not very good. 

8. Have we addressed any cigarette smoking habits?  Smoking is the single worst thing that a patient with diabetes can do.  It is the single worst thing anyone can do with regard to general health.  Again, because of the dramatically higher risk of heart attack and stroke with diabetes, stopping smoking can provide a HUGE gain in cardiovascular disease risk reduction over the subsequent two years. 

9.  Does the patient have appropriate dietary and lifestyle modification knowledge?  We need to make sure that our diabetic patients understand the dramatic effect of what we call "lifestyle" changes--diet, exercise, weight loss, and healthy living habits--has on improving longevity and quality of life.  Do they understand the concepts of an appropriate diabetic diet?  Do they understand the rationale of safely incorporating exercise into their routines?  

I have told many newly-diagnosed Type 2 diabetes patients that in my observation there are two types of diabetics:  Those who choose to confront the issues head-on and those who choose the "ostrich approach"--head in the sand.  If you choose to deal with the challenges of living with type 2 diabetes, you can get on top of it and reduce your risks and improve your life expectancy and quality of life.  If you "bury your head in the sand" and ignore the issues and act like you are "normal," you can expect a future filled with complications and misery and very likely a significantly shorter life.  My best diabetes patients have some obsessive/compulsive qualities--they monitor their blood sugars religiously, they monitor their blood pressures several times a week, they keep track of their medication, diet, and exercise habits and can tell me what effect each of those things has on their blood sugar. 

10.  Are they on the right medications?  Patients with type 2 diabetes who cannot control their blood sugars by diet and exercise alone will require medication.  Medication to help control their blood sugar.  They often also need medication to help control their cholesterol, as well as medication to help control their blood pressure. 

First line medications for controlling blood sugar start with metformin.  Metformin is a generally well-tolerated, inexpensive medication that improves the effectiveness of the body's own insulin.  It reduces that insulin "resistance" mentioned above.  The good thing about metformin is that it usually won't drive blood sugar too low.  Doses typically range from 500 mg a day to 2000 mg a day.  Beyond that we get into a point of diminishing returns, and more frequent side effects. 

If metformin is inadequate to control blood sugars, then we usual ADD a second medication--these "second-line" medications can be of several types.  Quite often we'll add a sulfonylurea medication such as glyburide or glipizide or glimepiride.  These are oral medications that increase the secretion of insulin from the beta-islet cells of the pancreas.  This sort of "forces" blood sugar down, but of course in doing so can sometimes result in blood sugars running too low.  Therefore, if a patient is started on one of these medications, they really must start monitoring their blood sugars frequently and consistently and be prepared for possible low-blood-sugar reactions, called hypoglycemia. 

Other medications used in addition to metformin are the DPP-4 inhibitors:  These are medications such as Januvia, Onglyza, and Trajenta, that reduce the effects of the hormone glucagon as well as triggering an increase in insulin.  Glucagon is a hormone that spurs blood sugar to rise especially after meals. 

There are other medications called GLP-1 agonists.  Examples of these are Byetta and Victoza.  These drugs trace their origins to the saliva of large lizards called Gila Monsters!  These are injectable medications that can significantly elevate insulin levels. 

Lastly, there is, of course, the option of starting on insulin.  Insulin can only be administered by injection. There are now many forms of insulin.  Generally we think of insulin in terms of long-acting and short-acting.  If a patient simply cannot be adequately controlled on the other medications listed above, then we usually start insulin in the form of a long-acting once daily form, which if done correctly gently brings ALL blood sugar levels down along a 24 hour period.  If more control is needed, then we'll usually add a short acting insulin injected before each meal, to prevent sugar spikes from each meal.  Of course, using insulin by injection runs a substantial risk of low blood sugars or an "insulin reaction," which can rarely be life-threatening.  Therefore frequent and careful blood sugar monitoring is required. 

Bottom Line:

It can be very overwhelming to a patient with newly diagnosed Type 2 diabetes.  If things are out of control, we as physicians are often required to start the patient on metformin, blood pressure medication, cholesterol medication, and a low dose aspirin daily.   The patient now has to become educated about and monitor their diet, work on exercise and weight loss, keep track of new medications, and keep track of upcoming office visits and expected lab tests.

But with time, almost everyone adjusts to the new reality of their situation, and it becomes the "new normal."  Pretty soon my patients are throwing around terms like "A1c" and "LDL" and "beta-islet cells" with confidence, as they have become more knowledgeable about their diabetes and its management.  I always hope that by making sure that my patients understand the issues, problems, risks and underlying biology of diabetes, they will be motivated to manage it appropriately.