Diagnosing diabetes mellitus in patients with porphyria cutanea tarda

Abstract

The prevalence of diabetes mellitus is increased in patients with porphyria cutanea tarda. Different tests are available for diagnosing and screening for type II diabetes mellitus, however choosing the most suitable test is challenging. The pitfalls in the different tests along with the interfering comorbidities and treatments concerning patients with porphyria cutanea tarda complicate diagnosing these patients with diabetes mellitus. HbA1c, fasting glucose, or oral glucose tolerance are the current available tests, with HbA1c as first choice. Measuring HbA1c requires no fasting, however HbA1c can be false low if the patient is treated with phlebotomy or has liver cirrhosis or chronic hepatitis. Instead fasting glucose and oral glucose tolerance tests can be used if the patient is not acutely ill. If either of the tests give a result in the diagnostic range, the test should be repeated if the patient has no clinical symptoms of diabetes. Diagnosing diabetes mellitus is important for the purpose of early intervention, and this review provides the knowledge needed to diagnose this special patient group properly.

Increased mortality in patients with porphyria cutanea tarda—A nationwide cohort study

“…Our expectation was based on previous studies showing that patients with PCT had a high prevalence of diabetes and high risk of stroke. We cannot explain this discrepancy between older studies and ours [10][11][12]17 .…”

“…Moreover, PCT patients also have an increased prevalence of impaired glucose tolerance and diabetes mellitus. The association between PCT and impaired glucose metabolism is not fully understood, but possibly implicates iron overload; a previous study showed that PCT patients with persistently high ferritin levels were more likely to develop impaired glucose metabolism and diabetes 10,11 .…”

Understanding Hepatic Porphyrias: Symptoms, Treatments, and Unmet Needs

“…84 Administration of estrogens via transdermal route is safe and recommended for at-risk women previously treated for PCT. 83 Hepatic siderosis, 6,83 systemic lupus erythematosus, 85 end-stage renal disease on hemodialysis, 86 diabetes mellitus, 87 and hematologic malignancies 88 are all associated with the development of PCT, 69,76 as is exposure to toxins such as polychlorinated biphenyls, hexachlorobenzene, and other polyhalogenated hydrocarbons that significantly induce CYP enzymes. 89…”