INvesTigating the Abnormality of detrusor ConTractility by uroflowmetry in diabetic children (INTACT Trial): protocol of a prospective, observational study

INTRODUCTION: Bladder emptying abnormalities and cardiovascular autonomic dysfunction are manifestations of autonomic dysfunction in people with diabetes mellitus (DM), which are major causes of morbidity and mortality. Since they can reduce the quality of life, they are urgent to be addressed before resulting in complications. As uroflowmetry might determine autonomic neuropathy earlier than cardiovascular autonomic dysfunction symptoms occur, our aim is to detect early abnormalities in bladder muscle function in children with DM. We investigate the diagnostic accuracy of uroflowmetry. As a secondary aim, we compare the prevalence of uroflowmetry abnormalities to the appearance of measures of cardiovascular autonomic neuropathy. Finally, as an ancillary study, we examine the association of uroflowmetry with the appearance of peripheral neuropathy. These three aims, we feel, will put our results regarding uroflowmetry into an overall context of nerve disease early in the course of type 1 DM. To our knowledge, such an approach has heretofore not been performed. METHODS AND ANALYSIS: This will be a prospective, observational, single-centre clinical study. Patients with DM fulfilling the inclusion criteria and healthy controls will have uroflowmetry examination, cardiovascular autonomic dysfunction tests (heart rate response to deep breathing, to Valsalva manoeuvre, blood pressure and heart rate response to standing up, and to sustained handgrip) and nerve conduction test. The autonomic nervous system function will be examined by the reproducible and standardised cardiovascular reflex tests described by Ewing et al. During the examination, electrocardiogram (ECG) and blood pressure values will be recorded continuously. Heart rate response to deep inspiration will be executed to investigate the parasympathetic nervous system. Peripheral neuropathy will be evaluated by nerve conduction test. After a pilot period, when the first 50 diabetic and 50 healthy children will be assessed, sample size calculation will be carried out. The primary objective of this trial is to evaluate the diagnostic accuracy (sensitivity, specificity, positive and negative predictive value) of uroflowmetry. To do so, we compare uroflowmetry to the gold standard neuropathy tests, which are cardiovascular autonomic dysfunction tests (heart rate response to deep breathing, to Valsalva manoeuvre, blood pressure and heart rate response to standing up and to sustained handgrip). ETHICS AND DISSEMINATION: Ethics approval was obtained from the Scientific and Research Ethics Committee of the Heim Pál National Paediatric Institute in Budapest, Hungary (registration number KUT-37/2021). Results will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT05247840.