Effects of Metformin Added to Insulin in Adolescents with Type 1 Diabetes: An Exploratory Crossover Randomized Trial

Table 3

Linear regression analyses for the association between metformin add-on treatment and changes in HRV indexes in youth with type 1 diabetes.

Model	Dependent variable	β-Coefficient	95% CI
Unadjusted model	ΔSDNN	24.25	1.10 to 47.39	0.04
	ΔSDANN	25.60	2.64 to 48.56	0.03
	ΔPNN50	9.33	2.70 to 15.97	<0.01
Multivariable model†	ΔSDNN	28.62	1.67 to 55.58	0.04
	ΔSDANN	31.0	2.76 to 59.24	0.03
	ΔPNN50	9.63	3.56 to 15.73	<0.01

All models with metformin treatment as independent variable. †Multivariable model with adjustment for changes in HbA1c, systolic blood pressure, and mean amplitude of glycemic excursions (MAGE). HRV: heart rate variability; CI: confidence interval; SDNN: standard deviation of all RR intervals; SDANN: standard deviation of all the 5-minute RR intervals; PNN50: the percentage of the interval differences of successive RR intervals greater than 50 ms.