Not all types of diabetes are created equal, and they vary in etiology, pharmacological management, musculoskeletal manifestations, nutritional goals, susceptibility for hypoglycemia, and responses to physical therapy treatment (outcomes). There seems to be a lack of regard in physical therapy documentation distinguishing type 1 and type 2 diabetes mellitus. The literature is lacking recommendations on specific components that should be included in the patient management model regarding patients with type 1 diabetes. Furthermore, there are other aspects in the care of patients with type 1 diabetes that clinicians may fail to address and that can predispose the patient to harm, such as the effect of exercise intensity on inducing hypoglycemia, management of hypoglycemia and hyperglycemia, and conditions under which a patient should not exercise. PTs may not be aware of the lesser-known complications directly caused by, or associated with diabetes, especially type 1 diabetes. Patients with diabetes may be referred for outpatient physical therapy for such conditions, but little emphasis or consideration may be given by clinicians regarding how poor glycemic control may manifest itself in these musculoskeletal disorders as this will alter expected outcomes and/or duration of treatment. 

Disease Overview

Diabetes mellitus consists of a group of disorders characterized by impaired blood glucose mechanism, of which type 1 diabetes accounts for 5% to 10% of diagnosed cases.¹ Patients with type 1 diabetes usually present with acute symptoms and markedly elevated blood glucose levels, requiring insulin for survival (as opposed to glycemic control as seen in type 2 diabetes). Type 1 diabetes occurs from pancreatic beta cell destruction due to an autoimmune response.² Risk factors may be autoimmune, genetic, or environmental. The category terms of “insulin-dependent diabetes” and “non-insulin dependent diabetes” have changed to type 1 and type 2 diabetes, which more appropriately describe the epidemiology. It has been noted that the terms insulin-dependent diabetes and non-insulin dependent diabetes have been misunderstood and misused when classifying patients with diabetes as some people with type 2 diabetes may require insulin for management of the disease.³ Similarities and differences between type 1 diabetes and type 2 diabetes are listed in Table 1.

Recently, there has been recognition of adults presenting with late-onset and slow progression of autoimmune diabetes and the terms “1.5 diabetes” and “latent diabetes of adults” (LADA) have been coined to describe this not-yet-officially-recognized sub-type of diabetes.⁴ Epidemiological data demonstrate that LADA accounts for about 10% of all cases of diabetes, making it as common as type 1 diabetes.⁵ Often, patients with LADA are diagnosed with type 2 diabetes because of the age at diagnosis (=30 years of age) and initial glycemic improvement with diet and oral agents, but they seem to more quickly progress to complete insulin deficiency. Patients with LADA share characteristics of both type 1 diabetes (positive antibodies⁶) and type 2 diabetes (although have fewer features of metabolic syndrome⁵). This sub-category of diabetes warrants mention because of similarities in management to type 1 diabetes. Due to the diagnostic confusion among patients with LADA, it may take longer for them to be effectively managed and expose them to hyperglycemia episodes that lead to complications despite the relative short time since diagnosis.

Medical history. More information is needed once the box indicating the patient has diabetes on the physical therapy intake sheet has been checked. Information regarding type and duration of diabetes, presence of diabetes complications, and management strategies used by the patient needs to be solicited and documented. Frequency of self-monitoring of blood glucose or the use of a continuous glucose sensor should be noted as well. The results of the Diabetes Control and Complications Trial,⁷ a landmark study, showed the positive effects of intensive insulin therapy, frequent glucose self-monitoring, and daily adjustments to food and insulin on lowering hemoglobin A1c (HbA1c) values and decreasing the risk of developing diabetes complications. An A1C (also known as glycated hemoglobin or HbA1c) blood test gives patients a picture of their average blood glucose control for the past two to three months. The amount of A1C in patients’ blood reflects blood sugar control for the past 120 days, or the lifespan of a red blood cell.

Patients should be re-evaluated periodically by their diabetes educator regarding the use of glucose self-monitoring to make adjustments to other disease management components. Patients who are less compliant with recommendations of monitoring their blood glucose may be unaware of hyperglycemia, hypoglycemia, and how to appropriately adjust insulin, food intake, and physical activity. Patient who perform more frequent glucose self-monitoring will have more information at their disposal to make changes in management, whereas the infrequent tester will not have as much information to impact self-management.

Insulin therapy. Based on the association between intensive management and lower risk of developing complications as found in the Diabetes Control and Complications Trial, the majority of type 1 diabetes patients are on multiple daily injections or insulin pump therapy.^2,8 Intensive treatment consists of three or more injections daily or use of an insulin pump. With multiple-daily injections, patients inject either intermediate or long-acting insulin to cover the basal requirements of insulin and take rapid or short-acting insulin when food is eaten. Multiple daily injections require timing food intake and physical activity based on the timed actions of the injected insulin. Even with long-acting insulin there is variability of absorption that can impact glycemic control.

Insulin pumps⁹ are insulin delivery systems that use rapid or fast-acting insulin only. They deliver small amounts of insulin at a time, making delivery and absorption more consistent, which is more equivalent to the normal physiological delivery of insulin. Pumps are the size of a beeper or small cell phone, and they release insulin into the interstitial tissue via an infusion set, like an IV, which is changed every two to three days. Additional insulin is programmed by the patient to be delivered when meals are to be eaten, much like the pancreas would release extra insulin when food is present in the body. The types of delivery are termed basal bolus and meal bolus respectively. Since there are no peaks in insulin to contend with, patients choose when to eat and how much.¹⁰ In order to do this, an insulin-to-carbohydrate ratio needs to be determined so patients know how much rapid-acting insulin is needed to cover the carbohydrate eaten at a meal or snack. This is used as part of a more advanced level of carbohydrate counting. Table 2 lists the more commonly used recombinant-DNA insulin preparations used for multiple daily injections and pump therapy.¹¹

Meal Planning. Carbohydrate counting is the meal-planning method commonly used by patients with type 1 diabetes to synchronize food choices with insulin to be delivered. Post-prandial (post-meal) blood glucose levels are used to modify the insulin-to-carbohydrate ratio. Unlike type 2 diabetics, who may have a weight loss goal as part of their medical nutrition therapy, patients with type 1 diabetes are only advised to maintain healthy eating habits² and rely on carbohydrate counting alone to determine insulin dosing.¹² One common misconception that many people, including PTs, have is that patients with type 1 diabetes need to follow a diabetic-diet or should avoid eating sugar. This is no longer true with type 1 diabetes; patients can partake of previously “forbidden foods” by using carbohydrate counting and becoming skilled at what effect those types of foods have on their blood glucose levels.¹³

Fats and protein have little effect on blood glucose levels unless consumed in large amounts, which can then reduce the absorption of carbohydrates. When eating fried or high-fat foods, patients may have elevated blood glucose levels four to six hours later, although their glucose levels were within target-range an hour or two after eating. Fiber recommendations are the same as for the general population and, due to the low glycemic index, have the added benefit of slowing down post-prandial rise in blood glucose.

Self-monitoring of blood glucose and continuous glucose monitoring. Frequent self-monitoring of blood glucose is crucial to patients with type 1 diabetes. Type 1 diabetics on multiple daily injections or pump therapy should carry out three or more glucose meter tests per day.² With more intensive glycemic control, there may be higher incidence of hypoglycemic episodes, as found in the Diabetes Control and Complications Trial. Continuous glucose monitoring devices have become available in recent years and are now more widely covered by insurance.¹⁴ Some systems integrate with insulin pumps to allow for round-the-clock monitoring of blood glucose.¹⁵ A small glucose sensor is inserted subcutaneously, and it sends data to the insulin pump via a radio-frequency transmitter. Glucose is measured from the interstitial tissue every minute, and average values are displayed every five minutes. Meter testing is still required for calibrating the system and ensuring the values are accurate before taking corrective actions. The system has an alarm function to alert when there are variations in glucose levels outside of the customizable, pre-programmed desired range. These alarms prompt the patient to correct fluctuations such as hypoglycemia and hyperglycemia promptly, thus preventing potential complications. It is the hope that someday this technology can be integrated fully with the pump — in essence, creating an external pancreas.

Other pharmacological agents. The American Diabetes Association recommends other beneficial pharmacological agents for patients with type 1 diabetes² used for treatment or prevention of cardiac and kidney complications. The medications and their purposes are outlined in Table 3. Clinicians should keep in mind side effects of certain medications, such as masking of hypoglycemia symptoms that occur with beta-blockers, decreased cardiac response with calcium channel blockers, and myalgia from statin medication.¹¹

Diabetes self-management education. Perhaps the most important part of the medical management of type 1 diabetes is diabetes self-management education, which provides the patient with assistance from healthcare professionals whose expertise is in diabetes.¹³ The intended key outcome of this education is for patients to maintain effective self-care of their diabetes as life-changes that alter glycemic control emerge and new treatment advances become available.² Certified diabetes educators teach patients how to adjust insulin to avoid the adverse effects of exercise, optimize glycemic control, recognize and treat hypoglycemia, prevent complications, and maximize quality of life. Many states mandate the cost of diabetes education be covered by insurance, as are medications and supplies.¹³

Special Considerations in Physical Therapy Management

Patients presenting to physical therapy after an injury or surgery will need more frequent glucose monitoring during the recovery process. Illness, trauma, and the physiologic stress of surgery can make glycemic control more difficult due to periods of physical inactivity and symptoms that accompany illness, such as nausea and vomiting, which can lead to hyperglycemia or hypoglycemia respectively.⁸ Significant elevations in blood glucose will require temporary adjustments in insulin requirements by the diabetes team. Patients with type 1 diabetes referred to physical therapy should be questioned regarding any changes in glycemic control since the injury or surgery. The effect of such physical or mental stress is likely to upset glycemic control and needs to be addressed within physical therapy treatment to promote optimal tissue healing, positively influence the rehabilitative process, and maximize rehabilitation outcomes.Although beneficial in improving glucose control and helping retard development of complications, patients with type 1 diabetes can find exercising challenging. The net effect of exercise on blood glucose levels is dependent on pre-exercise levels of glycemia, type and duration of exercise, and timing of medications and food intake.¹⁶ Based on the interaction of these factors, exercise may precipitate or worsen hypoglycemia or hyperglycemia. Knowledge of these interactions, along with frequent blood glucose monitoring, can reduce the likelihood of harmful blood glucose fluctuations during exercise.

Hypoglycemia, or low blood sugar, is the most common acute complication of diabetes. It is defined as a blood glucose level less than 70 mg/dl.^8,17 The causes are related to insulin-food-activity mismatch. Not recognizing the symptoms of hypoglycemia, ignoring them, or not acting on them quickly enough can lead to severe hypoglycemia, which is the point at which the individual is unable to treat him or herself. A glucagon injection kit is needed for treatment of severe hypoglycemia. Glucagon for injection is a polypeptide hormone identical to human glucagon that raises blood glucose by converting liver glycogen into glucose.¹⁸ All patients should have a kit prescribed, and PTs should be familiar with its administration. Table 4 reviews instructions on preparing and administering glucagon.  

Hypoglycemia unawareness can occur with long-standing diabetes because people lose their sensitivity to symptoms or feel them at much lower blood glucose levels;¹⁹ this mechanism has been found to be impaired in insulin-dependent people after two to five years with the disease. It is believed to be caused by neuropathic changes, which suppress the release of adrenaline, the hormone that triggers some of the symptoms. The neuroglycopenic (central nervous system) symptoms may be the only indicators of low blood sugar in people with hypoglycemia unawareness. Table 5 lists common symptoms, corresponding origin from the nervous system, and treatment of hypoglycemia. Recovery from hypoglycemia is dependent on symptom recognition and release of endogenous glucagon in response to dropping blood glucose levels, which signals the liver to release glucose into the bloodstream.

The “15/15 Rule”²⁰ is followed for treatment of conscious (mild) hypoglycemia. Fifteen grams of fast-acting carbohydrate is consumed, and blood glucose is reassessed in 15 minutes; glucose tablets or juice are recommended. If blood glucose is still below 70 mg/dl, treatment should be repeated with an additional 15 grams of carbohydrate. If the next meal to be consumed is more than an hour away, a snack consisting of an additional 15 grams of carbohydrate should be consumed to prevent blood glucose from falling again. The foods used to treat hypoglycemia should not include fat, such as a candy bar, as fat slows carbohydrate metabolism and will delay the rise in blood glucose. Glucose tablets should be available in physical therapy outpatient facilities, perhaps kept with the first-aid kit.

Low- to moderate-intensity exercise of at least 30 minutes duration²¹ lowers blood glucose in people with diabetes when pre-exercise levels are within normal ranges. The glucose lowering effects of exercise can be apparent in several hours and last up to 24 hours or more,²⁰ after the activity due to prolonged enhancement of insulin sensitivity and altered counter-regulatory response from the liver. Furthermore, hypoglycemia is more likely to occur after a previous episode of low blood sugar. Although the propensity for hypoglycemia in insulin-dependent diabetes is influenced by many factors, such as type and duration of insulin and exercise, safeguards can be taken to minimize the possibility of hypoglycemic episodes.

Patients should monitor blood glucose levels shortly before, during, and immediately after exercise. To help assess the response and tolerance to exercise and determine necessary adjustments in management, they should also monitor blood glucose several hours after exercise. Strategies to prevent hypoglycemia with exercise include decreasing insulin dosing, carbohydrate supplementation, or using a lower temporary basal rate in the pump. Reducing insulin dosage to prevent hypoglycemia may cause a rebound effect during the recovery period after exercise, resulting in elevated blood glucose levels — yet this is more easily managed than acute hypoglycemia. If patients have not received education on how to make these adjustments, they should be referred to a diabetes specialist for discussion.

Hyperglycemia is defined as blood glucose above 160 mg/dl; it is also the result of insulin-food-activity mismatch.²² Hyperglycemia may arise after a hypoglycemic episode, from overtreating it (too much carbohydrate), or from counter-regulatory hormones such as glucagon, cortisone, and epinephrine.⁸ Morning hyperglycemia can also occur if there was night-time hypoglycemia or from the “dawn phenomenon,” which is caused by early morning elevations of growth hormone. Patients may find elevated blood glucose after strenuous (high-intensity) exercise from too much carbohydrate supplementation, or lower levels of insulin during recovery, because insulin modulates the rate of muscle glucose uptake.¹⁵ Type 1 diabetics may perform high-intensity exercise, but they should keep the potential for hyperglycemia in mind and monitor pre-activity blood glucose levels. Insulin supplementation may be needed after high-intensity exercise.¹⁵ Managing hyperglycemic episodes is also imperative in diabetes control and should be monitored during treatment sessions.  Although not considered and immediately life-threatening complication of diabetes, hyperglycemia is what leads to vascular and tissue changes causing the well-known diabetes complications. When there is not enough exogenous insulin the body is unable to metabolize and use carbohydrate as an energy source which stimulates fat to be converted to energy to maintain body functions. Ketones are byproducts of fatty acid utilization for energy.²³ Once formed, ketones appear in the bloodstream and also spill into the urine causing dehydration.

In patients with type 1 diabetes, exercise alone will not lower pre-exercise hyperglycemia; insulin supplementation will be necessary to correct hyperglycemia. Patients should not exercise aerobically with hyperglycemia and when ketones are present as this could precipitate further increases in blood glucose from increased energy demand in the tissues. This situation may also lead to diabetic ketoacidosis, which is considered a medical emergency. Ketone testing is recommended when blood glucose is above 250 mg/dl. Symptoms of hyperglycemia and management are summarized in Table 5.

Poor glycemic control may lead to loss of protective sensation, which can appear before diabetic neuropathy. The neurological exam recommended by the American Diabetes Association is designed to identify loss of protective sensation. It consists of monofilament testing and at least one other test, including pinprick sensation, vibration perception (using a 128-Hz tuning fork), and ankle reflexes. Pedal pulses should be palpated as well.^2,24

Corticosteroid injections may be used in the management of certain musculoskeletal conditions, and physicians may not tell about the deleterious effect of these agents on glycemic control.²⁵ Hyperglycemia will likely ensue after injection of soft tissues or peritendinous areas requiring the patient to perform more frequent self-monitoring of blood glucose and increase insulin requirements. The effects can begin within 24 hours and continue from five to 21 days.^26,27,28

Some patients may not be as capable in self-management and will need assistance in problem-solving so they can safely and successfully complete therapy sessions, and some patients will require additional help from their diabetes specialist. Management of the type 1 diabetes patient in the physical therapy clinic needs to be individualized based on blood glucose measurements and the type of exercise to be performed. It will take some trial and error and a multidisciplinary approach to optimize treatment outcomes and maintain patient safety.

Lesser-known diabetes complications. Certain conditions and syndromes occur more frequently in people with diabetes compared to the general population. Clinicians may place little emphasis or give little consideration to how poor glycemic control may manifest itself in musculoskeletal disorders. These conditions would manifest themselves in patients with type 1 diabetes due to the cumulative effect of poorly controlled diabetes. Table 6 lists disorders, characteristics or physical findings, incidence, and management as presented in the literature.

The mechanisms by which musculoskeletal manifestations present in diabetes are not clearly understood, but glycosylation of proteins, microvascular abnormalities leading to damage to blood vessels and nerves, and collagen accumulation in the skin and periarticular structures are purported to cause changes in connective tissue.^{26,29,30,31,32} Commonly seen conditions in outpatient orthopedic physical therapy practices that emerge from these processes include diabetic cheiroarthopathy (diabetic stiff hand syndrome), flexor tenosynovitis (trigger finger), Dupytren’s contracture, adhesive capsulitis (frozen shoulder, diabetic stiff shoulder), calcific periarthitis, and complex regional pain syndrome.^32,33,34  Musculoskeletal complications are said to be more common in type 1 diabetes but also occur in patients with type 2 diabetes.³⁰ Furthermore, the literature notes people with diabetes are more recalcitrant to conservative treatment and have poorer outcomes with the conditions listed above.^26,35,36

Diabetic osteoarthopathy (neuropathic arthropathy or Charcot’s disease) arises from underlying diabetic neuropathy.^{29,30,31,32,34} Osteoporosis and osteopenia are theorized to be more common in people with diabetes due to decreased insulin-like factor and impaired calcium absorption, leading to lower bone mineral density.^31,32,37 Post-menopausal women with type 1 diabetes have an increased risk of hip fracture.^34,37 and osteolysis of the foot is associated with osteoporosis.³² Diffuse idiopathic skeletal hyperostosis (ankylosing hyperostosis) also occurs more frequently in patients with diabetes due to metaplastic calcification of spinal ligaments and osteophyte formation , which limits range of motion in the neck and back.^26,31,34 Diabetic muscle infarction and diabetic amyotrophy occur in type 1 diabetes and type 2 diabetes respectively; infarction presents as acute onset of pain and swelling over the affected muscle groups, and amyotrophy presents as acute muscle weakness and wasting.^29,31,34  Patients on statin therapy may also present with myalgia, which is muscle tenderness or stiffness from rhabdomyolisis.^31,38

The physical therapy profession has focused on type 2 diabetes, perhaps because it is preventable or modifiable and encompasses the majority of patients with diabetes. When type 1 diabetes is addressed specifically, complications such as diabetic neuropathy or ulcers dominate the literature. The physical therapy profession would benefit by establishing a standard of care for patients with type 1 diabetes that can improve patient safety and lead to more appropriate prognosis and outcomes. Diabetes management in physical therapy needs to be specific to the particular type, not all patients with diabetes lumped into one homogenous group. PTs should be comfortable with the self-monitoring of blood glucose and interpretation of values as related therapy interventions, and they should be prepared to treat hypoglycemia. Patients will benefit from the clinicians’ involvement by providing encouragement of performing self-care skills and exercising active problem solving. Referral to the diabetes specialist should be done when the patient is lacking these skills.

Comprehensive outpatient physical therapy care of a patient with type 1 diabetes requires special considerations and knowledge. Contemplation of key differences in etiology and management of type 1 diabetes from other types of diabetes, guidelines for self-monitoring of blood glucose and insulin therapy, hypoglycemia and hyperglycemia recognition and treatment, the musculoskeletal manifestations of diabetes mellitus, and the effects of exercise on blood glucose will guarantee individualized and thoughtful service delivery by clinicians.