Acne vulgaris linked to insulin resistance

Levels of insulin resistance markers tend to be elevated in patients with acne vulgaris, supporting the association between acne vulgaris and insulin resistance, according to the results of a systematic review and meta-analysis.

However, the researchers have not found any beneficial effect of isotretinoin, a vitamin A metabolite used for the treatment of acne vulgaris, in improving insulin resistance in this population.

This study, presented at the 29th Congress of the European Academy of Dermatology and Venereology (EADV 2020), sought to examine the relationship of acne vulgaris with plasma insulin level, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and serum adiponectin among patients with and without acne, as well as to assess the effect of isotretinoin on these insulin resistance markers.

The researchers, led by Harmanjit Singh from the Govt Medical College and Hospital in Chandigarh, India, conducted a comprehensive search through PubMed, Embase, Scopus, Central, and Web of Science using specific strategy from inception to 6 April 2019.

Clinical trials and observational studies investigating the association between the acne vulgaris and levels of plasma insulin, HOMA-IR, and serum adiponectin levels were included. Two researchers independently carried out the selection of studies, and a third researcher evaluated the quality of included studies using the Newcastle Ottawa Scale.

Data from these studies were pooled and expressed as the mean difference (MD) with 95 percent confidence interval (CI). Homogeneity assessment was done using I2 statistics.

A total of 1,142 records were evaluated for full texts, which yielded 14 studies that met the eligibility criteria for the meta-analysis. Twelve studies included data for the association between acne vulgaris and insulin levels (679 patients with acne and 587 controls), 10 studies for HOMA-IR (601 with acne and 534 controls), and four and three studies had data on the effect of isotretinoin on serum insulin and HOMA-IR, respectively.

Acne patients, as compared to control participants, had significantly increased levels of plasma insulin (MD, 2.77 micro U/ml, 95 percent CI, 1.37–4.17; p=0.0001) and HOMA-IR (MD, 0.62, 95 percent CI, 0.21–1.04; p=0.003). Data on adiponectin could not be pooled due to discrepancy of differences in units. [EADV 2020, abstract P0010]

On the other hand, isotretinoin did not produce any beneficial effects on the above parameters (p=0.71 and p=0.12 for the effect on plasma insulin levels and HOMA-IR, respectively).

A recent study, however, suggested that 5 months of isotretinoin therapy in acne vulgaris patients resulted in insulin resistance. Moreover, the increase in insulin resistance was not dependent on age, body mass index, body fat mass, and lipid levels. [Turk J Med Sci 2019;49:238-244]

“Acne vulgaris is a chronic inflammatory disease of pilosebaceous unit and is one of the manifestations of hyperandrogenism,” the researchers said. “Insulin resistance and compensatory hyperinsulinaemia have been shown to stimulate adrenal androgen synthesis and inhibit the hepatic production of sex hormone binding globulin, allowing for an increase in androgen bioavailability, and is one of the common factors to cause acne vulgaris.”