Course of Type 1 Diabetes Markedly Improved in Past 25 Years

The typical long-term course of type 1 diabetes has dramatically improved during the past 25 years, according to the results of two long-term observational studies.

This improvement includes decreases in the incidence of proliferative retinopathy, nephropathy, and cardiovascular disease, as indicated in a report in the July 27 issue of the Archives of Internal Medicine.

Modern-day therapy for both diabetes and its comorbidities can be expected to cut the complication rate by more than half of what it used to be, said Dr. David M. Nathan and his associates in the Diabetes Control and Complications Trial (DCCT) and the Epidemiology of Diabetes Interventions and Complications (EDIC) trial.

Noting that most published descriptions of the clinical course of type 1 diabetes are outdated, the DCCT/EDIC research group assessed data collected from the DCCT in 1983-1993 and data from the follow-up study of the same subjects, the EDIC trial, from 1993 to 2005.

The study subjects were 1,441 males and females aged 13-39 years at baseline who were randomly assigned to receive conventional (at that time) diabetes treatment or more intensive treatment. Since then, intensive treatment has become the standard of care.

A total of 1,375 subjects continued in the EDIC follow-up study, undergoing annual physical examinations and assessment of diabetic complications, said Dr. Nathan of Massachusetts General Hospital and Harvard Medical School, Boston, and his colleagues in the DCCT/EDIC Research Group.

After an average of 30 years of diabetes duration and in the setting of intensive treatment for approximately 20 of those years, the cumulative incidence of proliferative retinopathy is 21%, that of nephropathy is 9%, and that of cardiovascular disease is also 9% in these subjects.

“Of note, only 5 of 1,441 DCCT participants had a loss in visual acuity worse than 20/100 in either eye ... and only 3 subjects ever became legally blind in both eyes.” Only 36 subjects developed renal insufficiency, and only 15 required amputations, with 14 of these involving only toes, Dr. Nathan and his associates said (Arch. Intern. Med. 2009;169:1307-16).

These figures stand in stark contrast to the 40%-53% rates of retinopathy and the 35% rate of nephropathy reported in cohorts of people in comparable studies who developed diabetes 10-20 years earlier than did the DCCT subjects, they added.

The investigators confirmed these findings by conducting a similar analysis of data from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study, which took place during a similar time frame and had a similar methodology. They examined a 161-patient cohort of the EDC study chosen to match the DCCT entry criteria. As with the DCCT/EDIC trial, the EDC study demonstrated “the powerful effect of intensive therapy over time,” they stated.

“The long-term clinical outcome results in the DCCT conventional treatment group, confirmed by the EDC study data, provide a reliable sense of the clinical course that can be expected with modern-day therapy during the past 25 years,” the researchers said.

“The prospects for patients with type 1 diabetes are far better than they were in the past,” they stated.

“Intensive therapy, now the standard of care, should result in more than 50% reduction in the rates of complications over time, with the implementation early in the course of diabetes providing the most powerful salutary effect,” the researchers concluded.

No financial conflicts of interest were reported.

Copyright (c) 2009 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

译文：

据两项长期观察性研究发现，在过去的25年里，具有典型长病程的1型糖尿病发生了显著改善。

 

发表在7月27日出版的当期《内科学文献》杂志上的一项报告称，这些改善包括增殖性视网膜病、肾病和心血管疾病的发病率有所降低。

 

与过去相比，糖尿病和其共病的现代疗法可将并发症的发生率降低一半以上，David M. Nathan博士和同事们在报告中说，他们进行了糖尿病控制和并发症临床研究（DCCT）和糖尿病干预和并发症流行病学研究（EDIC）。

 

注意到大多已发表的有关1型糖尿病临床病程的描述均已过时，DCCT/EDIC的研究者分析了来自1983～1993年进行的DCCT研究和随后进行的其随访研究（EDIC研究，1993～2005年）的数据。

 

研究受试者为1,441例基线年龄在13～39岁的男女患者，患者被随机分配接受当时的常规糖尿病疗法或更为强化的治疗。其后，强化治疗成为标准疗法。

 

来自麻省总医院和波士顿哈佛大学医学院DCCT/EDIC研究组的Nathan博士和同事说，共1,375例患者参与了其后的随访研究EDIC，研究中患者每年进行体检并评估糖尿病性并发症情况。

 

在平均30年的糖尿病病程并在其间接受约20年的强化治疗后，这些患者增殖性视网膜病的累积发病率为21%，肾病和心血管病均为9%。

 

 “值得注意的是，1,441例受试者中仅5例某一只眼视敏度低于20/100，仅3例双目失明。仅36例发生肾功能不全，仅15例需要截肢，其中14例仅脚趾受累，”Nathan博士和同事说 (Arch. Intern. Med. 2009;169:1307-16)。

 

研究者补充道：一些与DCCT具有可比性的队列研究的数据与以上数据差异显著，这些研究中的患者比DCCT受试者早10～20年发生糖尿病，这些患者的视网膜病的发病率为40%～53%，肾病的发病率为35%。

 

研究者通过对匹茨堡糖尿病并发症流行病学研究（EDC）的数据进行相同的分析后确证了这些发现，EDC研究与DCCT研究几乎同时进行，研究方法也相似。研究者对EDC中与DCCT入组标准相匹配的161例患者进行了分析。与DCCT/EDIC研究相同，EDC研究显示了“长期强化治疗的强力效应”。

 

研究者们说：“DCCT常规疗法组的长期临床结果得到EDC研究的证实，它在过去25年里为我们展现了1型糖尿病临床病程的实际情况，并可由现代疗法带来显著改变。”

 

 “1型糖尿病患者的预后远好于过去，”研究者说。

 

 “强化疗法现在已成为标准治疗，可将长期并发症的发生率降低一半以上，在糖尿病病程早期开始实施可带来显著获益，”研究者总结道。

 

研究者否认研究中存在利益冲突。