Differential impact of timing of nocturnal hypoglycemia on subjective sleep quality in people with type 1 diabetes.

BACKGROUND

The impact of nocturnal hypoglycemia (NH) on subjective sleep quality in type 1 diabetes (T1D) is unclear. Awareness to stimuli varies across sleep stages-lower during early slow-wave sleep and higher during late sleep-which may influence the impact of NH on perceived sleep quality. This study examines whether NH timing affects subjective sleep quality in T1D.

METHODS

Adults with T1D using multiple daily injections or basic insulin pumps (excluding real-time continuous glucose monitoring [CGM] users) wore a blinded CGM (Freestyle Libre Pro) for 14-28 days and rated sleep quality each morning using a single-item Likert scale (1 = very poor; 5 = very well). Sleep time was defined as 0000-0600 h, split into early (0000-0300) and late (0300-0600) periods. NH was categorized as Time-Below-Range, TBR1 (<70 mg/dL) and TBR2 (<54 mg/dL). A cumulative link mixed model assessed the impact of NH during early (TBR-E) and late (TBR-L) sleep on sleep quality, with participant as a random effect.

RESULTS

Among 27 participants (18 women), median age was 30.6 years, mean BMI 24 kg/m2, median diabetes duration 16 years, and median HbA1c 7.6 %. Over half used insulin pumps, all used insulin analogs. NH during late sleep significantly reduced the odds of reporting better sleep quality (OR 0.90, 95 % CI: 0.86-0.94, p < 0.001). TBR1-E and TBR2 showed no association. Adjusting for age, gender, BMI, HbA1c, and diabetes duration did not change these findings.

CONCLUSION

NH timing may be a key determinant of subjective sleep quality in T1D.