9.                Tuberculosis and Diabetes Patients*   

A "positive" PPD skin test (i.e., >10 mm induration 48-72 hours after administration) means that a person either has latent tuberculosis infection (LTBI) or active tuberculosis (TB) disease. Active TB disease needs to be ruled out prior to starting patients with LTBI on treatment. Treatment for active TB and LTBI are different*. 

Patients with diabetes and LTBI are at high risk of progressing to active TB, if they are not treated for LTBI.  Studies have shown that the risk is 2 to 6 times greater than in patients without diabetes. Other factors that further increase the risk for TB include: recent PPD conversion within 2 years, intravenous drug use, chest film showing prior active disease that was never treated, immunosuppressive drugs, and ESRD.  Cutaneous anergy increases as patients age and develop complications of diabetes such as ESRD.  Anergy may lead to false negative PPD test results.

In most cases progression of LTBI to active TB can be prevented by treatment with INH.  In general, patients with diabetes who have a positive PPD (accurately read by a provider trained in interpretation of PPD) should receive treatment for LTBI, except in the following circumstances:

          ·        severe liver disease

·        suicidal ideation

·        adverse reaction to INH  

Patients receiving treatment for LTBI should be followed and monitored for potential hepatotoxicity.  While national recommendations emphasize monitoring hepatotoxicity through systematic repetitive patient education and clinical evaluation for signs and symptoms of hepatotoxicity, baseline measurement of liver function tests and after one month should be considered, especially in patients receiving other potentially heptotoxic medications.  Some experts recommend that INH be discontinued if transaminase levels exceed three times the upper limit of normal when associated with symptoms or five times the upper limit of normal if the patient is asymptomatic.  

IHS TB Protocol for Patients with Diabetes: 

·  Check the PPD status of all patients with diabetes. 

·   If the PPD status is negative or unknown:

-  PPD testing should be done within one year of initial work up for diabetes diagnoses, and            treated if they have LTBI. 

-  If no PPD has been placed since the diagnosis of diabetes, and the patient's PPD status is            negative or unknown, a PPD status needs to be ascertained.  

-  Subsequent PPD testing is done only if there is contact with an active TB case.

·  If the PPD status is positive:

-  Check for completion of past treatment for active TB or LTBI (6-9 months of INH for LTBI or multiple   drug therapy for active disease).

-         If the patient has not been adequately treated, search for active disease by history (weight loss, etc), fever (record temperature) and recent chest x-ray (within 6 months). If there is no evidence of active disease, recommend treatment for LTBI (9 mos. of INH 300 mg daily) to all patients with diabetes, regardless of age, unless the patient has liver disease, suicide ideation    or a previous adverse reaction to INH.  Patients with diabetes should be given pyridoxine (10-50 mg/day) with their INH.  Consider directly observed therapy of LTBI when possible, especially for patients on dialysis.

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*Recommendations for targeted tuberculin testing and treatment of LTBI in MMWR, June 09, 2000/ 49(RR06); 1-54 or at  www.cdc.gov/mmwr//indrr_2000.html  Or at:   Treatment for active TB disease is detailed in: CDC Core Curriculum in TB: What the Clinician Should Know. CDC, 2000 (4^th edition).