To the Editor: The life expectancy of patients with type 1 diabetes continues to improve. Better care has reduced the frequency of organic complications and improved their management. But what is the impact upon quality of life? Two studies, the UK Golden Years cohort [1] and the 50 year Joslin Medalist study [2], have examined the clinical characteristics of type 1 diabetic patients with long disease duration. Here we describe a Parisian cohort and evaluate the lifestyle of patients suffering from this chronic disease for 50 years.

Investigators (J.-J. Altman, S. Feldman-Billard) at two centres followed 57 patients with a mean duration of type 1 diabetes of 49.8 ± 7.6 years on an outpatient basis over several decades. Standard clinical data, common laboratory tests and regular screening for chronic complications were recorded, as well as markers of metabolic control and diabetes treatment (Table 1

Table 1 Characteristics of the 57 patients of the Parisian Cohort
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). All patients gave informed consent and completed a quality of life questionnaire during a routine visit. The main items on the questionnaire were marital status with description of offspring, physical activity and social life (cultural, training, travelling, sexual activity). Data concerning professional life included: educational level, professional activity, retirement, working days missed because of the disease and impact on professional life. The patients were also asked to classify the burdens impairing their life, to evaluate the main improvements in the treatment of the disease during their lifetime and to specify the most helpful person/organisation in their life (see text box). Statistical analysis was performed with the SPSS statistical software version 14.0 for Windows (SPSS, Chicago, IL, USA). The variables presented were summarised as means ± SD.

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Mean systolic and diastolic blood pressure was 137.4 ± 22.9 and 78.4 ± 9.5 mmHg, respectively. Treatment and monitoring followed the rules of intensified therapy, but mean HbA1c was 8.6 ± 1.3%; only 10% of patients had an HbA1c value below 7%. Mean HDL-cholesterol was higher than 1.25 mmol/l in 86% of patients. Poor vision, with visual acuity < 20/200, was present in 19% of the patients, with a similar number having serum creatinine above 120 μmol/l. Only one patient had no evidence of diabetic retinopathy [3] and five were blind. Three others had functioning kidney grafts, combined with a pancreas graft in one case. Two were on regular haemodialysis.

Some 81% of patients had married and 9% were divorced; 84% of patients had at least one child. On average, they had 1.40 ± 1.23 (range 0–4) children and 1.24 ± 1.96 (0–7) grandchildren, with no difference between men and women. Only five men and four women had no children. All but two were independent. Physical activity of more than 30 min per day was reported by 86% and gardening by 25%. Social life was rated as being impaired by 54%, but nearly all patients went regularly to the cinema (93%), theatre (81%) or restaurants (91%). Half engaged in sport on a regular basis, and 60% made use of public transport; the same proportion travelled regularly, mostly abroad. Regular sexual activity was reported in the past by 81% and was current in 60%. Educationally, 60% had a university degree; all but three patients were employed (90% full time), none had asked for early retirement and 40% were still working at the time of the study. Fifty-four per cent had never missed work because of diabetes, although half considered that the condition had restricted their professional activity.

The most frequently reported burdens were the need to self-monitor blood glucose, the need for perpetual diet, visual impairment and insulin injections. The four most popular improvements were the use of laser therapy in the management of chronic complications, followed by glucose monitoring, insulin pens and disposable equipment. In order of importance, the most helpful persons in their life were their spouse, their diabetologist and their general practitioner (see text box).

A quarter of a century ago, the life expectancy of a 25-year-old type 1 diabetic patient, was 33 years [4]. Our patients had a mean period of 35 years free from significant complications impairing their life. Our type 1 diabetic Parisian cohort resembled the Golden Years cohort [1]. Macroangiopathy was rarely present, because of, at least in part, a favourable cholesterol ratio [5]. In the 50 year Medalist study, HDL-cholesterol was high and mean HbA1c was elevated as in our group, but close to half did not report any significant microvascular complications [2]. The Medalist study also reported a lack of association between glycaemic control and the prevalence of such complications [2]. The low dose of insulin needed was comparable to ours. The authors of the above two studies [1, 2] speculate that their patients could possibly be protected by a favourable genetic background. Fertility was initially described as reduced in type 1 diabetic women but normalisation has occurred in more recent cases [6]. It is notable that in our cohort the fertility ratio was the same in women as in men.

All our patients were followed by the same practitioners for decades and the questionnaires were completed after about 50 years of diabetes. In other studies, quality of life questionnaires were mainly addressed to patients with a rather shorter duration of diabetes [7, 8]. It is not possible to compare our cohort with non-surviving patients selected by the time and age of diagnosis. Comparison with type 2 diabetic patients is not relevant. Of course, our cohort was selected by life, environment, socio-cultural status, genes and metabolism, as well as many other possibilities. We have no way of demonstrating which of these factors is the most prominent. This important problem was not the focus of our study. Importantly, for whatever reason, we have been able to show that a rather large cohort of patients with type 1 diabetes, a previously fatal disease, were able to enjoy familial, professional and socio-cultural success. For diabetic patients, who spend so much time and effort coping with their disease, this is a truly optimistic message.