Commonly Measured Clinical Variables Are Not Associated With Burden of Complications in Long-standing Type 1 Diabetes: Results From the Canadian Study of Longevity in Diabetes

Twenty-five percent of individuals with long-standing type 1 diabetes (T1D) are resistant to complications, and this is not entirely explained by superior glycemic control (1–4). Although associations between clinical variables and individual complications have been comprehensively examined (1–4), analysis of total complication burden may detect previously unrecognized associations. The Canadian Study of Longevity in Diabetes actively recruited 325 individuals who had T1D for 50 or more years (5). Subjects completed a questionnaire, and recent laboratory tests and eye reports were provided by primary care physicians and eye specialists, respectively. Nephropathy was defined by an albumin-to-creatinine ratio of >2 mg/mmol for participants on an ACE inhibitor or angiotensin receptor blocker (ARB) or >3.4 mg/mmol for participants not on an ACE inhibitor or ARB. Symptomatic neuropathy was defined by a score ≥3 on the Michigan Neuropathy Screening Instrument (MNSI) questionnaire component. Retinopathy was defined by documentation of nonproliferative or proliferative retinopathy in the eye specialist report. Coronary artery disease was defined by self-reported …