Intraperitoneal versus subcutaneous insulin therapy in the treatment of type 1 diabetes mellitus

Background: Continuous intraperitoneal insulin infusion (CIPII), a last-resort type 1 diabetes mellitus (T1DM) treatment, has only been investigated in small or controlled studies. We aimed to investigate glycaemia and quality of life (QoL) with CIPII versus subcutaneous (SC) insulin therapy during usual T1DM care.Methods: A prospective, observational case-control study. CIPII-treated cases were matched to SC controls. The primary endpoint was a non-inferiority assessment (pre-defined margin of -5.5 mmol/mol) of the baseline adjusted difference in HbA1c between groups during a 26-week follow-up. Secondary outcomes included QoL, clinical and biochemical measurements.Results: In total, 183 patients were analysed (CIPII n = 39 and SC n = 144). The HbA1c difference between treatment groups was -3.0 mmol/mol (95% CI -5.0, -1.0), being lower in the SC group. Patients using SC insulin therapy spent less percentage of time in hyperglycaemia (-9.3% (95% CI -15.8, -2.8)) and more in euglycaemia (6.9% (95% CI 1.2, 12.5) as compared with CIPII-treated patients. Besides a 3.6 U/l (95% CI 1.2, 6.0) lower concentration of alanine aminotransferase with CIPII, no biochemical and clinical differences were present. Most QoL scores were lower at baseline among CIPII-treated patients. However, besides lower health status, there were no differences in the baseline-adjusted general and diabetes-specific QoL and treatment satisfaction.Conclusion: Although patients using CIPII had a higher glycaemic profile compared with patients using SC insulin therapy, the HbA1c difference was non-inferior. Overall, health status was lower among CIPII-treated patients, although diabetes-specific QoL and treatment satisfaction was similar to subcutaneously treated patients.