Phenotypic characterization of patients with type 2 diabetes mellitus

Type 2 diabetes mellitus harbors heterogeneity. This study describes the phenotypic subgroups based on anthropometric and biochemical characteristics.

This was a cross-sectional study involving 96 patients with early type 2 diabetes conducted from July 2017 to December 2018. Clinical history was recorded and anthropometric measurements were done. Beta cell function was estimated using oral disposition index (DIo). Homeostatic model assessment for insulin resistance (HOMA-IR) was calculated using the fasting plasma glucose and fasting insulin levels. The cut off to define insulin resistance was 1.93.

The median age was 53.5 years. Fifty-five (57.3%) patients were males. Thirty-two percent of females and 33% of males had a BMI of less than 23 kg/m². The average DIo was 0.54. Insulin resistance was present in 59 (61.5%) of the total patients. Three subgroups of patients were discernible. One, predominantly insulin resistant (HOMA-IR > 1.93)]: 61.45%; second, predominant beta cell dysfunction (HOMA-IR 1–1.93)]: 26%; and third, severely reduced beta cell function (HOMA-IR < 1)]: 12.5%. Insulin-resistant men could be identified with 87.5% specificity if BMI of more than 25.56 and waist circumference (WC) more than 91.8 cm. Insulin-resistant women could be identified with 100% specificity if their WC was more than 97 cm.

Three phenotypic subgroups were discernible with 40% of patients having predominant insulin deficiency. It is important to identify patients belonging to these subgroups so as to tailor their treatment accordingly.