La pertinencia de las TIC en la educación

This section is aimed at assisting with identifying HIV-positive patients on highly active antiretroviral therapy who are at risk of developing diabetes mellitus. The diagnosis, monitoring and management of such patients is discussed.

resistance with resultant reduced glucose consumption, and also increase hepatic gluconeogenesis.

26.3 Antiretroviral drugs and the development of

diabetes

Antiretroviral drugs are the major cause of the development of diabetes in patients with HIV. Five classes of antiretroviral drugs are currently available in South Africa:

1. Nucleoside reverse transcriptase inhibitors (NRTIs): stavudine, zidovudine, lamivudine, abacavir, didanosine, tenofovir, emtricitabine

2. Non-nucleoside reverse transcriptase inhibitors (NNRTIs): efavirenz, nevirapine, etravirine

3. Protease inhibitors (PIs): indinavir, ritonavir, lopinavir, saquinavir, atazanavir, darunavir

4. Entry inhibitors: enfuvirtide

5. Integrase inhibitors: raltegravir.

The NRTIs cause dysglycaemia, mainly by three mechanisms:

1. Mitochondrial toxicity: This is responsible for the lactic acidosis for which these drugs are notorious. Lactic acidosis, in turn, leads to increased adipocyte apoptosis, with a resultant reduction in fat-cell mass (lipoatrophy) and, therefore, an increase in insulin resistance. Stavudine and didanosine have most often been implicated but, as treatment guidelines are being updated, these drugs are being phased out. The newer NRTIs (e.g. abacavir) are metabolically neutral.

2. Lipodystrophy.

3. Pancreatitis.

NNRTIs, fusion inhibitors and integrase inhibitors are metabolically neutral.

PIs induce insulin resistance by: 1. Lipodystrophy

2. Impaired glucose transporter type 4 (GLUT 4) translocation

3. Reduced adipocyte differentiation, by inhibition

of peroxisome proliferator-activated receptor γ

(PPAR-γ).

4. Reduced insulin secretion

5. Dyslipidaemia with lipotoxicity (indirectly).

The exact mechanism of PI-induced lipodystrophy remains unknown, but some studies have reported that up to 83% of patients on a PI develop lipodystrophy, and 35% of those go to develop diabetes. It is important to note that not all PIs are the same. Older-generation PIs

(e.g. indinavir, ritonavir, saquinavir, lopinavir) are mainly responsible for insulin resistance at therapeutic dosages. However, these drugs are now only being used in PI- boosted regimens, with the exception of lopinavir and ritonavir. The newer-generation PIs (e.g. atazanavir, darunavir) are considered metabolically neutral.

26.4 Screening, diagnosis and monitoring

26.4.1 Screening

Everybody with the risk factors discussed earlier should be screened. For the non-HIV population, the recommendations are to repeat screening every three years but, in HIV-positive patients with risk factors, the frequency should be every six months. Fasting plasma glucose is the preferred test.

26.4.2 Diagnosis

The same diagnostic criteria for diabetes apply for HIV- positive as for HIV-negative patients. The same can be said of diagnostic methods but, in HIV-positive patients, an oral glucose-tolerance test is the preferred method.

Glycated haemoglobin (HbA_1c) is not a recommended

diagnostic test in HIV-positive patients, because of the effects of the virus on haemoglobin, co-morbid conditions, and the effects of some antiretroviral drugs (e.g. zidovudine suppresses the bone marrow).

26.4.3 Monitoring

The same guidelines for self-monitoring of blood glucose (SMBG) apply for HIV-positive as for HIV-negative patients. SMBG is largely dependent on the kind of treatment the patient is on (e.g. oral agents vs. insulin, basal insulin vs. multiple insulin injections)

HbA_1c is still regarded as the gold standard in terms of monitoring for long-term glycaemic control, but the patient’s general health and medical history must be taken into consideration as well.

26.5 Glycaemic targets

The HbA_1c target is < 7% for the majority of patients, with the exception of those who are already terminally ill or have advanced HIV-associated nephropathy, where the risk of hypoglycaemia will be high. Glycaemic targets should, therefore, be individualised.

26.6 Management

26.6.1 General management

Once again, the same general measures apply in HIV-positive and HIV-negative patients. However, it is important to remember the following in the HIV positive: • Exclude sexually transmitted infections and, if

present, treat appropriately.

• Exclude opportunistic infections, particularly

tuberculosis, and, if present, treat appropriately. • Exclude hepatitis C and, if present, treat

appropriately.

• Avoid the use of so-called “immune boosters”. • Advise against use of traditional medicines.

• Advise the patient to stop smoking; this includes the

use of snuff.

• Encourage psychosocial support from particularly the family, particularly since the patient will now have been diagnosed with two chronic diseases, and exclude depression.

• Emphasise and re-emphasise the importance of compliance for both diseases.

26.6.2 Medical treatment 26.6.2.1 Treatment of diabetes

The general principles for the use of both oral antidiabetic drugs and insulin apply but, in the HIV-positive patient, the following are important:

Exclude HIV-associated nephropathy (HIVAN) before initiating metformin, because lactic acidosis can occur. The gastrointestinal side-effects of metformin are increased in those with HIV enteropathy. Start at a very low dose and titrate up gradually.

Stavudine and didanosine are being discontinued but, in those who are still being treated with these drugs, do not prescribe metformin, because lactic acidosis can occur.

26.6.2.2 Treatment of HIV

Metabolically neutral antiretroviral drugs should be prescribed in patients who are at high risk of developing diabetes. These include abacavir, atazanavir, darunavir, tenofovir and emtricitabine.

Stavudine, didanosine, lopinavir, sequinavir and indinavir should be avoided.

Bibliography

1. The South African HIV guidelines 2011

2. Calza L, Manfredi R, Chiodo F. Insulin resistance and diabetes mellitus in HIV infected patients receive antiretroviral therapy.

3. Grinspoon S. Mechanism and strategies for insulin resistance in acquired immune deficiency syndrome.

4. Kalra S et al. Understanding diabetes in patients with HIV/AIDS. 5. Samaras K, et al. Metabolic consequences and therapeutic options in

highly active antiretroviral therapy in human immunodeficiency virus-1 infection.

27.1 Fasting during Ramadaan

Fasting during the holy month of Ramadaan constitutes

one of the five fundamental pillars of Islam. Muslims abstain

from food and drink from dawn (Suhur) to dusk (Iftaar). Despite the fact that those who are ill are exempted from this obligation, many Muslims with diabetes mellitus (diabetes) still wish to fast.1 _{Patients with diabetes that} fast are at risk of hypoglycaemia, hyperglycaemia and dehydration. Those who plan to fast need to undergo an assessment of risk before Ramadaan, and must participate in a structured education programme addressing meal planning, physical activity, dosage and timing of medications, glucose monitoring and the recognition and management of untoward events, including hypoglycaemia.2

The following individuals with diabetes are permitted to

fast:

• Well-controlled patients with type 2 diabetes being treated with insulin, a short-acting insulin secretagogue (glinide), or a sulphonylurea, or a combination oral or oral plus insulin treatment. These patients can fast, provided they consult a healthcare professional several months before Ramadaan and make the necessary changes to their therapy. • Well-controlled patients being treated with dietary

adjustment alone, monotherapy with metformin, dipeptidyl peptidase-4 (DPP-4) inhibitors, or thiazolidinediones, and who are otherwise healthy. Fasting is contraindicated in idividuals with:

• Type 1 diabetes

• Severe and recurrent episodes of hypoglycaemia

with unawareness

• Poor glycaemic control

• Ketoacidosis within the three months before

Ramadaan

• Hyperosmolar hyperglycaemic state within the three months before Ramadaan

• Severe acute illness

• Occupations that require intense physical labour • Co-morbidities, such as advanced macrovascular

complications, renal insufficiency, cognitive dys- function, and uncontrolled epilepsy (particularly when precipitated by hypoglycaemia)

• Pregnant women

27.2 Approach to patients with type 2 diabetes

planning to fast during Ramadaan

The patients should be assessed two to four months before Ramadaan.4

27.2.1 Medical assessment

The healthcare provider should follow an individualised approach for each patient. The overall glycaemic control, blood pressure, lipid profile and renal function should be assessed. Body weight and body mass index should be measured and recorded. The diabetes medication regimens should be assessed, and the treatment of choice, timing and dosage adjustments should be communicated to the patient.