Association between depression and concurrent Type 2 diabetes outcomes varies by diabetes regimen

Aims Although depression has weak associations with several Type 2 diabetes mellitus (DM) outcomes, it is possible that these associations are concentrated within certain patient subgroups that are more vulnerable to their effects. This study tested the hypothesis that depression is related to glycaemic control and diabetes‐related quality of life (DQOL) in patients who are prescribed injected insulin, but not those on oral glucose‐lowering agents alone. Methods Participants (103 on insulin, 155 on oral glucose‐lowering agents alone) with Type 2 DM were recruited from a large US healthcare system and underwent assessment of glycaemic control (glycated haemoglobin; HbA_1c), medication adherence and diabetes self‐care behaviours, DQOL and depression (none, mild, moderate/severe). Results There was a significant regimen × depression interaction on HbA_1c (P = 0.002), such that depression was associated with HbA_1c in patients using insulin (β = 0.35, P < 0.001) but not in patients using oral agents alone (β = –0.08, P = NS). There was a similar interaction when quality of life was analysed as an outcome (P = 0.002). Neither effect was mediated by regimen adherence. Conclusions The generally weak association between depression and glycaemic control is concentrated among patients who are prescribed insulin. Similarly, the association between depression and illness quality of life is strongest in patients prescribed insulin. Because this is not attributable to depression‐related adherence problems, psychophysiological mechanisms unique to this group ought to be carefully investigated. Clinicians might be especially vigilant for depression in Type 2 DM patients who use insulin and consider its potential impact upon their illness course.     

Addressing insulin resistance in Type 1 diabetes

Type 1 diabetes is recognised to include an element of insulin resistance. Insulin resistance is an independent risk factor for the development of macro‐ and microvascular complications of Type 1 diabetes and may also contribute to the development of the disease. This understanding comes at a time when the incidence of Type 1 diabetes appears to be rising and the public health burden from its vascular complications is high. A variety of safe and efficacious manoeuvres are available to redress insulin resistance in Type 2 diabetes. So far however, clinical trials addressing insulin resistance in Type 1 diabetes have been small with only short periods of follow‐up. Regardless, these trials have yielded promising results. This review examines the evidence for insulin resistance in the pathophysiology of Type 1 diabetes and its complications, the problems associated with its measurement, and summarizes the trials aimed at reducing insulin resistance in Type 1 diabetes. This includes a meta‐analysis of controlled trials of adjuvant metformin in Type 1 diabetes.     

The locus of control in patients with Type 1 and Type 2 diabetes managed by individual and group care

Aims The locus of control theory distinguishes people (internals) who attribute events in life to their own control, and those (externals) who attribute events to external circumstances. It is used to assess self‐management behaviour in chronic illnesses. Group care is a model of systemic group education that improves lifestyle behaviour and quality of life in patients with Type 1 and Type 2 diabetes. This study investigated the locus of control in Type 1 and Type 2 diabetes and the possible differences between patients managed by group care and control subjects followed by traditional one‐to‐one care. Methods Cross‐sectional administration of two questionnaires (one specific for diabetes and one generic for chronic diseases) to 83 patients followed for at least 5 years by group care (27 Type 1 and 56 Type 2) and 79 control subjects (28 Type 1 and 51 Type 2) of similar sex, age and diabetes duration. Both tools explore internal control of disease, the role of chance in changing it and reliance upon others (family, friends and health professionals). Results Patients with Type 1 diabetes had lower internal control, greater fatalistic attitudes and less trust in others. Patients with either type of diabetes receiving group care had higher internal control and lower fatalism; the higher trust in others in those with Type 1 diabetes was not statistically significant. The differences associated with group care were independent of sex, age and diabetes duration. Conclusions Patients with Type 1 diabetes may have lower internal control, fatalism and reliance upon others than those with Type 2 diabetes. Receiving group care is associated with higher internal control, reduced fatalism and, in Type 1 diabetes, increased trust in others.     

Ketoacidosis occurs in both Type 1 and Type 2 diabetes— a population‐based study from Northern Sweden

Aims To determine the occurrence of diabetic ketoacidosis (DKA) in adult Type 2 and Type 1 diabetic patients in Northern Sweden and to determine whether DKA presents with a different clinical picture in Type 2 compared with Type 1 diabetic subjects. Methods All adult patients from a hospital catchment area in Northern Sweden with diagnosed DKA episodes during 1997–2000 were included in a retrospective study. Medical records and laboratory reports were analysed. Results During the years 1997 to 2000, the average annual incidence rate for DKA was 5.9 per 100 000 adult inhabitants. Twenty‐five patients developed DKA, eight (32%) had Type 2 diabetes, while 17 (68%) had Type 1 diabetes. Type 2 diabetic patients with DKA were older and had higher levels of C‐peptide than Type 1 diabetic patients. On admission because of DKA, a similar degree of hyperglycaemia was present in Type 1 and Type 2 patients. Metabolic acidosis was more severe in Type 1 compared with Type 2 diabetic patients. In 50% of the Type 2 diabetic patients, diabetes was diagnosed at the episode of DKA. Conclusions DKA occurs in Caucasian Type 2 diabetic patients within a Swedish population. Although the frequency of DKA is much higher in Type 1 diabetic patients, Type 2 diabetes may account for as much as one‐third of the overall DKA cases.     

Different role of zinc transporter 8 between type 1 diabetes mellitus and type 2 diabetes mellitus

Diabetes can be simply classified into type 1 diabetes mellitus and type 2 diabetes mellitus. Zinc transporter 8 (ZnT8), a novel islet autoantigen, is specifically expressed in insulin‐containing secretory granules of β‐cells. Genetic studies show that the genotypes of SLC30A8 can determine either protective or diabetogenic response depending on environmental and lifestyle factors. The ZnT8 protein expression, as well as zinc content in β‐cells, was decreased in diabetic mice. Thus, ZnT8 might participate in insulin biosynthesis and release, and subsequently involved deteriorated β‐cell function through direct or indirect mechanisms in type 1 diabetes mellitus and type 2 diabetes mellitus. From a clinical feature standpoint, the prevalence of ZnT8A is gradiently increased in type 2 diabetes mellitus, latent autoimmune diabetes in adults and type 1 diabetes mellitus. The frequency and epitopes of ZnT8‐specific T cells and cytokine release by ZnT8‐specific T cells are also different in diabetic patients and healthy controls. Additionally, the response to ZnT8 administration is also different in type 1 diabetes mellitus and type 2 diabetes mellitus. In the present review, we summarize the literature about clinical aspects of ZnT8 in the pathogenesis of diabetes, and suggest that ZnT8 might play a different role between type 1 diabetes mellitus and type 2 diabetes mellitus.     

Safety and efficacy of inhaled insulin (AERx® iDMS1) compared with subcutaneous insulin therapy in patients with Type 1 diabetes: 1‐year data from a randomized,parallel group trial

Aims Assessment of the long‐term safety and efficacy of liquid inhaled insulin via AERx^® insulin Diabetes Management System (iDMS) in a basal/bolus treatment regimen of adults with Type 1 diabetes. Methods Patients were randomized 2 : 1 to prandial inhaled (n = 205) or subcutaneous (s.c.) (n = 99) insulin, plus one/two daily injections of neutral protamine Hagedorn (NPH) insulin for 12 months. The primary endpoints were pulmonary function tests (PFT) and baseline changes in chest X‐rays at 12 months. Safety and efficacy assessments were measured at regular intervals. Results PFTs after 12 months were comparable between the groups, except for reduced per cent of predicted carbon monoxide lung diffusing capacity with inhaled insulin (difference: –2.03%, P = 0.04) occurring after the first 3 months and then stabilizing. There were no apparent treatment differences in chest X‐rays. Overall risk of hypoglycaemia [risk ratio (RR) 1.02, P = 0.83] and adverse events were comparable between groups. Risk of nocturnal hypoglycaemia was higher in the inhaled group (RR 1.58, P = 0.001). Cough [10% (inhaled); 3% (s.c.)] tended to be mild in nature. Inhaled insulin was non‐inferior to s.c. insulin for change in glycated haemoglobin (HbA_1c) after 12 months [difference 0.18% (CI 95%–0.04; 0.39)]. At trial end, mean laboratory measured fasting plasma glucose was lower in the inhaled group (inhaled 9.2 mmol/l; s.c. 11.7 mmol/l; difference: –2.53 mmol/l, P < 0.001). Conclusions The safety and efficacy results in this trial were similar to those reported with other inhaled insulins; however, inhaled insulin using AERx^® iDMS requires further optimization to reduce nocturnal hypoglycaemia before it has comparable safety and efficacy to s.c. insulin aspart.     

New potential treatments for protection of pancreatic B‐cell function in Type 1 diabetes

Type 1 diabetes mellitus results from the progressive and specific autoimmune destruction of insulin‐secreting pancreatic B‐cells, which develops over a period of years and continues after the initial clinical presentation. The ultimate goal of therapeutic intervention is prevention or reversal of the disease by the arrest of autoimmunity and by preservation/restoration of B‐cell mass and function. Recent clinical trials of antigen‐specific or non‐specific immune therapies have proved that modulation of islet specific autoimmunity in humans and prevention of insulin secretion loss in the short term after the onset of disease is achievable. The identification of suitable candidates for therapy, appropriate dosage and timing, specificity of intervention and the side‐effect profile are crucial for the success of any approach. Considering the complexity of the disease, it is likely that a rationally designed approach of combined immune‐based therapies that target suppression of B‐cell specific autoreactivity and maintenance of immune tolerance, coupled with islet regeneration or replacement of the destroyed B‐cell mass, will prove to be most effective in causing remission/reversal of disease in a durable fashion.     

Elevated plasma prostaglandins and acetylated histone in monocytes in Type 1 diabetes patients

Aims/hypothesis Inflammation is implicated in diabetes and cyclooxygenase (COX) is involved in vascular inflammatory processes, participating in both atherosclerosis and thrombosis. The aims were to determine whether levels of monocyte COX and plasma COX metabolites are increased in Type 1 diabetic patients and to determine whether these could be linked to histone hyperacetylation. Materials and methods Monocytes from 19 Type 1 diabetic and 39 non‐diabetic control subjects were probed for COX and acetylated histone H4 proteins by immunoblotting. Plasma COX metabolite levels [thromboxane B₂ (TXB₂) and prostaglandin E₂ (PGE₂)] were determined by enzyme immunoassay. Results Monocyte COX‐2 expression was significantly up‐regulated (1.3‐fold) in diabetic relative to the non‐diabetic control subjects and plasma PGE₂ was markedly elevated (2.7‐fold). In diabetic subjects, monocyte acetylated histone H4 levels were significantly elevated; sub‐group analysis indicated that the increased histone acetylation was found only in the complication‐free group. Conclusions Results support increased inflammatory activity in Type 1 diabetes that involves COX‐2 and increased prostaglandin production, which may predispose patients to cardiovascular events. The observation of elevated histone acetylation only in complication‐free diabetic subjects suggests that this may be a protective mechanism. This merits further investigation as histone hyperacetylation has been associated with reduced expression of factors involved in vascular injury and remodelling.     

Safety and efficacy of glargine compared with NPH insulin for the treatment of Type 2 diabetes: a meta‐analysis of randomized controlled trials

Aims We systematically analysed evidence from randomized controlled trials (RCTs) examining the safety and efficacy of neutral protamine Hagedorn (NPH) insulin and glargine in the management of adults with Type 2 diabetes. Methods Studies were identified by searching medline (1966–March 2007), embase (1974–2007), American Diabetes Association abstract database and the Cochrane Central Register of Controlled Trials using Medical Subject Headings (MeSH) diabetes mellitus, Type 2, insulin, insulin isophane, hypoglycaemic agents and the keywords glargine and NPH. Data on study design, participants, fasting plasma glucose (FPG), glycated haemoglobin (HbA_1c), body weight and hypoglycaemia were independently abstracted by two investigators using a standardized protocol. Results Data from a total of 4385 participants in 12 RCTs were pooled using a random‐effects model. The mean net change (95% confidence interval) for FPG, HbA_1c and body weight for patients treated with NPH insulin as compared with glargine was 0.21 mmol/l (?0.02 to 0.45), 0.08% (?0.04 to 0.21) and ?0.33 kg (?0.61 to ?0.06), respectively, with negative values favouring NPH and positive values favouring glargine. More participants experienced symptomatic and nocturnal hypoglycaemia on NPH than glargine, but there was no significant difference in confirmed or severe episodes. Conclusions We identified no difference in glucose‐lowering between insulin glargine and NPH insulin, but less patient‐reported hypoglycaemia with glargine and slightly less weight gain with NPH in adults with Type 2 diabetes.     

Insulin and glucose profiles during continuous subcutaneous insulin infusion compared with injection of a long-acting insulin in Type 2 diabetes1

Aims To compare insulin and glucose profiles during basal continuous subcutaneous infusion of a rapid-acting insulin analogue and once daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes. Methods Twenty-one patients with Type 2 diabetes treated with oral glucose-lowering agents were randomized in this two-period crossover study to an equivalent 24-h dose of continuous subcutaneous infusion of insulin aspart and subsequently once-daily bedtime subcutaneous injection of insulin glargine, or vice versa, for eight consecutive days. Plasma profiles of insulin and glucose were recorded. Results On the last day of each treatment period, the area under the curve (AUC) for glucose was 10% lower on the continuous subcutaneous infusion regimen compared with the insulin injection regimen (P = 0.002). This was accomplished by a flat exogenous insulin infusion profile compared with a peaking profile with injected insulin (AUC was 74% higher after injection compared with pre-injection levels (P = 0.001)). During the last 6 days in each treatment period, the intra-subject variability of exogenous fasting insulin levels in the mornings was 41% lower during insulin infusion compared with insulin injection (P = 0.012). The corresponding intra-subject variability for fasting glucose only showed a tendency to be lower during infusion as compared to the injection regimen (28%; P = 0.104). Thirteen symptomatic-only or minor hypoglycaemic episodes were recorded during the entire infusion period compared with three episodes during the injection period. Conclusions Basal continuous subcutaneous infusion of a rapid-acting insulin analogue improved plasma insulin (more flat insulin profile with a lower variability) and glucose (lower AUC) profiles compared with once-daily subcutaneous injection of a long-acting insulin analogue in Type 2 diabetes.     

Incidence and trends of childhood Type 1 diabetes worldwide 1990–1999

Aims To examine incidence and trends of Type 1 diabetes worldwide for the period 1990–1999. Methods The incidence of Type 1 diabetes (per 100 000/year) was analysed in children aged ≤ 14 years from 114 populations in 112 centres in 57 countries. Trends in the incidence of Type 1 diabetes were analysed by fitting Poisson regression models to the dataset. Results A total of 43 013 cases were diagnosed in the study populations of 84 million children. The age‐adjusted incidence of Type 1 diabetes among 112 centres (114 populations) varied from 0.1 per 100 000/year in China and Venezuela to 40.9 per 100 000/year in Finland. The average annual increase in incidence calculated from 103 centres was 2.8% (95% CI 2.4–3.2%). During the years 1990–1994, this increase was 2.4% (95% CI 1.3–3.4%) and during the second study period of 1995–1999 it was slightly higher at 3.4% (95% CI 2.7–4.3%). The trends estimated for continents showed statistically significant increases all over the world (4.0% in Asia, 3.2% in Europe and 5.3% in North America), except in Central America and the West Indies where the trend was a decrease of 3.6%. Only among the European populations did the trend in incidence diminish with age. Conclusions The rising incidence of Type 1 diabetes globally suggests the need for continuous monitoring of incidence by using standardized methods in order to plan or assess prevention strategies.     

Effect of weight‐reducing agents on glycaemic parameters and progression to Type 2 diabetes: a review

Weight loss is associated with improvements in glycaemic control and cardiovascular disease risk factors. However, in the diabetic population, weight management is more challenging, in part because of the weight‐promoting effects of the majority of glucose‐lowering therapies. This review summarizes evidence from 23 placebo‐controlled randomized trials, of at least 1 year duration, on the effects of drugs promoting weight loss (orlistat, sibutramine and rimonabant) on glycaemic variables, diabetes incidence and diabetes control. Fifteen studies of non‐diabetic subjects were found, eight of which included a longer treatment period. Eight studies in diabetic patients were reviewed. In non‐diabetic subjects, weight loss agents led to a significant improvement in fasting glucose, fasting insulin and insulin resistance. In the diabetic population, glycated haemoglobin decreased by 0.28–1.1% with orlistat and 0.6% with sibutramine and rimonabant. Orlistat reduces progression to diabetes in patients with glucose intolerance treated for 4 years (risk reduction of 45%). In summary, despite leading to only modest weight loss after 12 months, agents promoting weight loss have beneficial effects on glycaemic parameters, glycaemic control and progression to diabetes. These additional benefits of weight loss agents need to be highlighted in order to increase their judicious use in clinical practice, although this may be limited by their well‐known adverse side effects. The longer‐term safety of these agents beyond a few years is yet to be established.     

Hypoglycaemia in insulin-treated Type 2 diabetes: frequency,symptoms and impaired awareness

Aims Hypoglycaemia is considered to be less common in people with insulin-treated Type 2 diabetes than in Type 1 diabetes. A retrospective survey was made of 215 people with insulin-treated Type 2 diabetes to quantify the frequency and nature of hypoglycaemia experienced. Methods The frequencies of mild (self-treated) and severe (required assistance) hypoglycaemia during the preceding year were estimated retrospectively. The usual symptoms of hypoglycaemia and state of awareness of hypoglycaemia were scored using validated questionnaires and any history suggestive of impaired hypoglycaemia awareness was documented. Results In this cohort, 157 (73%) had experienced hypoglycaemia since commencing insulin, the frequency of which increased with duration of diabetes and of insulin therapy and was inversely related to current HbA_1c (all P < 0.05). During the preceding year, 32 individuals (15%) had experienced severe hypoglycaemia, with an estimated incidence for the entire group of 0.28 episodes/patient/year. Principal components analysis revealed two underlying symptom groups (autonomic and neuroglycopenic), similar to those reported previously by young adults with Type 1 diabetes, but the total symptom score declined with advancing age. Of the 157 with a history of hypoglycaemia, the 13 (8%) individuals who gave a history of impaired awareness of hypoglycaemia had experienced a ninefold higher incidence of severe hypoglycaemia than those with normal awareness, and reported experiencing mainly neuroglycopenic symptoms. Conclusions While the overall frequencies of mild and severe hypoglycaemia were lower in insulin-treated Type 2 diabetes than have been reported previously in Type 1 diabetes, the risk of hypoglycaemia was greater with increasing duration of diabetes and of insulin therapy. Although impaired awareness of hypoglycaemia was uncommon, it was associated with a higher incidence of severe hypoglycaemia. Diabet. Med. 20, ***–*** (2003)     

Service quality for Type 2 diabetes in Australia: the patient perspective

Aims To assess the service quality of care as perceived by people with Type 2 diabetes mellitus. Methods A cross-sectional survey using a self-administered questionnaire was carried out among members of Diabetes Australia–Queensland with Type 2 diabetes. For 12 aspects of service quality derived from a literature review and focus group research, patients scored the relative importance of the aspects and their perception of quality of received care. A measure of service quality was derived by combining the relative importance and actual performance. Results A total of 603people with Type 2 diabetes participated. Of the 12 aspects of care, communication, availability of support group, safety and prevention had the highest scores for importance; support group and basic amenities had the highest average performance values; but the highest service quality values were for support group, basic amenities, dignity and confidentiality. Younger participants had lower service quality scores (P = 0.001) and participants with good control of their diabetes had higher scores (P < 0.001). Compared with the reference population, our sample had 8.7% fewer people under 65 years old. Conclusions From the perspective of people with Type 2 diabetes, there is a notable gap between their expectations and what they have actually received in most aspects of provided care. In addition, overall service quality and six aspects of service quality (choice of care provider, accessibility, prevention, continuity, timeliness and safety) were identified to be of inadequate quality. Hence, this study demonstrates a significant opportunity to improve quality of healthcare services.     

The prevalence of coronary heart disease in Type 2 diabetic patients in Italy: the DAI study

Aims Type 2 diabetes is associated with at least a twofold increase in risk of coronary heart disease (CHD). We aimed to estimate the prevalence of CHD in the population of Type 2 diabetics cared for by the Italian network of outpatient diabetic units. Methods The DAI ( D iabetes and Informatics study group, Italian A ssociation of Diabetologists, and I talian National Institute of Health) study is a multicentre cohort study of patients with Type 2 diabetes. Patients were classified as having CHD if they had: (i) a history for hospital admission for either an acute myocardial infarction (AMI) or angina; (ii) a positive ECG for prior AMI or angina; (iii) a positive history for coronary artery bypass graft; or (iv) a positive history for percutaneous transluminal coronary angioplasty. Results A cohort of 19 468 patients was analysed: 3157 patients had CHD. The majority of events (80%) had occurred after the diagnosis of diabetes and were considered in the CHD prevalence estimate. The prevalence of CHD, adjusted by age and sex, was 9.9%: 11.0% male and 9.0% female. Angina without AMI occurred in 1306 patients; this condition was more frequent in females while a documented AMI was more frequent in males. Therapeutic procedures were performed more frequently in males. A positive association with CHD was found for gender, age at visit, duration of diabetes, hypertension, relatives with CHD, tryglicerides and microvascular complications. Conclusions The prevalence of CHD in this cohort is lower than previously reported; nevertheless, patients attending the diabetic care units may not be fully representative of the general diabetic population in Italy. Revascularization is less frequent in females than in males; microvascular complications and a worse metabolic control are significantly associated with CHD.     

Acute hyperglycaemia disturbs cardiac repolarization in Type 1 diabetes

Aims Patients with Type 1 diabetes have an increased risk of cardiovascular mortality. Notably, a prolonged heart rate adjusted QT interval (QTc) is a predictor of sudden cardiovascular death. Therefore, the objectives of this study were to investigate whether acute hyperglycaemia affects the QTc duration and the QTc dispersion in patients with Type 1 diabetes and in healthy volunteers. Methods Acute hyperglycaemia (15 mmol/l) for 120 min was induced in 35 males (22 men with Type 1 diabetes and 13 age‐matched non‐diabetic volunteers). All participants were non‐smokers without any diabetic complications. Electrocardiogram recordings were performed at normoglycaemia and at 0, 60 and 120 min of hyperglycaemia. Results Compared with normoglycaemia, acute hyperglycaemia increased the QTc interval in both patients with Type 1 diabetes (390 ± 6 vs. 415 ± 5 ms, P < 0.001) and in healthy volunteers (378 ± 5 vs. 412 ± 8 ms, P < 0.01). During hyperglycaemia, the QTc dispersion was prolonged in healthy volunteers (36 ± 4 ms vs. 54 ± 7 ms, P < 0.05) but not in patients with Type 1 diabetes (45 ± 3 ms at baseline vs. 48 ± 5 ms, NS). Conclusions Acute hyperglycaemia alters myocardial ventricular repolarization in patients with Type 1 diabetes and in healthy volunteers and might consequently be an additional risk factor for cardiovascular events.     

Paraoxonase 1 phenotype distribution and activity differs in subjects with newly diagnosed Type 2 diabetes (the CODAM Study)

Aims Paraoxonase 1 (PON1) is an antioxidant high‐density lipoprotein‐bound enzyme, which was recently found to be expressed in the islets of Langerhans. A substitution (Q/R) at position 192 results in enzymes with different activity. Oxidation has been implicated in the onset of diabetes, and it can be hypothesized that PON1 may have a protective effect on diabetes. Our aim was to compare PON1 activities and PON1 Q/R phenotypes in subjects with different degrees of glucose intolerance. Methods We examined 566 members of the Cohort study of Diabetes and Atherosclerosis Maastricht (CoDAM), including subjects with normal glucose tolerance (NGT, n = 298), impaired glucose regulation (IGR, n = 128), newly diagnosed Type 2 diabetes (nDM, n = 78) and treated, that is to say known, Type 2 diabetes (kDM, n = 64). PON1 activity was measured in serum using paraoxon and diazoxon as substrates. The PON1 phenotype was determined using two‐dimensional enzyme analysis. Results The RR‐phenotype was significantly more frequent in nDM compared with NGT subjects (14.1 vs. 6.0%, P = 0.05). Adjusted for the PON1 phenotype, subjects with nDM had significant lower PON1 activity towards paraoxon and diazoxon than subjects with NGT. Adjusted odds ratios comparing the RR‐variant with the QQ‐variant were 2.17 [95% confidence interval (CI): 0.90–5.24] for impaired glucose tolerance, 2.84 (95% CI: 1.03–7.83) for nDM, 2.13 (95% CI; 0.61–7.42) for kDM and 2.65 (95% CI: 1.10–6.40) for total diabetes mellitus. Conclusions An aberrant PON1 phenotype distribution and PON1 activity were observed in early diabetes. In addition, the higher state of oxidative stress may affect the future development of complications.     

Quality of life in children with Type 1 diabetes: a comparison of general and diabetes‐specific measures and support for a unitary diabetes quality‐of‐life construct

Aims To assess the factor structure of the Pediatric Quality of Life Inventory (PedsQL) Diabetes Module and to compare the PedsQL general and diabetes‐specific quality of life (QOL) measures regarding psychometric properties and relations to relevant outcomes. Methods The instruments were completed by 447 children age 9 to 15.5 years with Type 1 diabetes > 1 year from four US paediatric diabetes clinics; parents completed the parallel parent‐proxy measures. Principal components factor analysis was used to examine the factor structure of the PedsQL diabetes module. Analyses of the generic and diabetes QOL measures included psychometric properties, parent–child correlations and correlations with depression, adherence and glycated haemoglobin (HbA_1c). Results The factor structure of the PedsQL diabetes module did not support the original five subscales. Both one‐ and two‐factor models were supported; however, parallel parent and child subscales did not emerge. While the generic and diabetes‐specific measures of QOL were moderately to highly correlated with each other, the constructs were differentially associated with relevant diabetes outcomes. Generic QOL was more highly associated with depression than diabetes QOL. Conversely, diabetes QOL was more highly associated with adherence and HbA_1c, although this was seen to a greater extent for parent‐proxy report than for child report. Conclusions Factor analysis of the PedsQL diabetes module supports the use of a total diabetes QOL score. Findings regarding the associations of the generic and diabetes modules with diabetes outcomes underscore the unique contribution provided by both generic and diabetes QOL.